diff --git a/README.MD b/README.MD
index 66956203..7354892e 100644
--- a/README.MD
+++ b/README.MD
@@ -49,11 +49,9 @@ As OpenInv is compiled against Mojang's mappings, you must run BuildTools with t
 `java -jar BuildTools.jar --remapped --rev $serverVersion`  
 `$serverVersion` is the version of the server, i.e. `1.18.1`
 
-To compile for a single version, specify the module you are targeting:  
-`mvn -pl $moduleName -am clean install`  
-`$moduleName` is the name of the module, i.e. `internal/v1_18_R1`.
+To compile just the API, execute Maven as usual:  
+`mvn clean package`  
 
-To compile for a set of versions, use a profile. Select a profile using the `-P` argument:  
+To compile the full plugin, use the provided profile with `-P all`:  
 `mvn clean package -am -P all`  
-The only provided profile is `all`. The final file is `target/OpenInv.jar`  
 For more information, check out the [official Maven guide](http://maven.apache.org/guides/introduction/introduction-to-profiles.html).
diff --git a/api/src/main/java/com/lishid/openinv/IOpenInv.java b/api/src/main/java/com/lishid/openinv/IOpenInv.java
index d1e0155f..7c4e1bc8 100644
--- a/api/src/main/java/com/lishid/openinv/IOpenInv.java
+++ b/api/src/main/java/com/lishid/openinv/IOpenInv.java
@@ -17,21 +17,19 @@
 package com.lishid.openinv;
 
 import com.lishid.openinv.internal.IAnySilentContainer;
-import com.lishid.openinv.internal.IInventoryAccess;
 import com.lishid.openinv.internal.ISpecialEnderChest;
 import com.lishid.openinv.internal.ISpecialInventory;
 import com.lishid.openinv.internal.ISpecialPlayerInventory;
-import com.lishid.openinv.util.InventoryAccess;
-import java.util.UUID;
-import java.util.logging.Logger;
 import org.bukkit.Bukkit;
 import org.bukkit.OfflinePlayer;
 import org.bukkit.entity.Player;
 import org.bukkit.inventory.InventoryView;
-import org.bukkit.plugin.Plugin;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
+import java.util.UUID;
+import java.util.logging.Logger;
+
 /**
  * Interface defining behavior for the OpenInv plugin.
  */
@@ -80,22 +78,6 @@ public interface IOpenInv {
      */
     @NotNull IAnySilentContainer getAnySilentContainer();
 
-    /**
-     * @deprecated Use static {@link InventoryAccess} methods.
-     */
-    @Deprecated(forRemoval = true)
-    default @NotNull IInventoryAccess getInventoryAccess() {
-        return new InventoryAccess();
-    }
-
-    /**
-     * @deprecated Use {@link #getAnyContainerStatus(OfflinePlayer)}. Not all containers are chests.
-     */
-    @Deprecated(forRemoval = true, since = "4.2.0")
-    default boolean getPlayerAnyChestStatus(@NotNull OfflinePlayer offline) {
-        return getAnyContainerStatus(offline);
-    }
-
     /**
      * Get whether a user has AnyContainer mode enabled.
      *
@@ -104,14 +86,6 @@ default boolean getPlayerAnyChestStatus(@NotNull OfflinePlayer offline) {
      */
     boolean getAnyContainerStatus(@NotNull OfflinePlayer offline);
 
-    /**
-     * @deprecated Use {@link #setAnyContainerStatus(OfflinePlayer, boolean)}. Not all containers are chests.
-     */
-    @Deprecated(forRemoval = true, since = "4.2.0")
-    default void setPlayerAnyChestStatus(@NotNull OfflinePlayer offline, boolean status) {
-        setAnyContainerStatus(offline, status);
-    }
-
     /**
      * Set whether a user has AnyContainer mode enabled.
      *
@@ -120,14 +94,6 @@ default void setPlayerAnyChestStatus(@NotNull OfflinePlayer offline, boolean sta
      */
     void setAnyContainerStatus(@NotNull OfflinePlayer offline, boolean status);
 
-    /**
-     * @deprecated Use {@link #getSilentContainerStatus(OfflinePlayer)}. Not all containers are chests.
-     */
-    @Deprecated(forRemoval = true, since = "4.2.0")
-    default boolean getPlayerSilentChestStatus(@NotNull OfflinePlayer offline) {
-        return getSilentContainerStatus(offline);
-    }
-
     /**
      * Get whether a user has SilentContainer mode enabled.
      *
@@ -136,14 +102,6 @@ default boolean getPlayerSilentChestStatus(@NotNull OfflinePlayer offline) {
      */
     boolean getSilentContainerStatus(@NotNull OfflinePlayer offline);
 
-    /**
-     * @deprecated Use {@link #setSilentContainerStatus(OfflinePlayer, boolean)}. Not all containers are chests.
-     */
-    @Deprecated(forRemoval = true, since = "4.2.0")
-    default void setPlayerSilentChestStatus(@NotNull OfflinePlayer offline, boolean status) {
-        setSilentContainerStatus(offline, status);
-    }
-
     /**
      * Set whether a user has SilentContainer mode enabled.
      *
@@ -152,20 +110,6 @@ default void setPlayerSilentChestStatus(@NotNull OfflinePlayer offline, boolean
      */
     void setSilentContainerStatus(@NotNull OfflinePlayer offline, boolean status);
 
-    /**
-     * Get a unique identifier by which the OfflinePlayer can be referenced.
-     *
-     * @deprecated Use {@link OfflinePlayer#getUniqueId()} and {@link UUID#toString()}. This was necessary for non-UUID
-     * versions of Minecraft, but support for them has been dropped for years.
-     * @param offline the OfflinePlayer
-     * @return the identifier
-     * @throws IllegalStateException if the server version is unsupported
-     */
-    @Deprecated(forRemoval = true)
-    default @NotNull String getPlayerID(@NotNull OfflinePlayer offline) {
-        return offline.getUniqueId().toString();
-    }
-
     /**
      * Get an {@link ISpecialEnderChest} for a user.
      *
@@ -229,55 +173,6 @@ default void setPlayerSilentChestStatus(@NotNull OfflinePlayer offline, boolean
      */
     @Nullable OfflinePlayer matchPlayer(@NotNull String name);
 
-    /**
-     * @deprecated OpenInv uses action bar chat for notifications. Whether they show is based on language settings.
-     */
-    @Deprecated(forRemoval = true)
-    default boolean notifyAnyChest() {
-        return true;
-    }
-
-    /**
-     * @deprecated OpenInv uses action bar chat for notifications. Whether they show is based on language settings.
-     */
-    @Deprecated(forRemoval = true)
-    default boolean notifySilentChest() {
-        return true;
-    }
-
-    /**
-     * @deprecated see {@link #retainPlayer(Player, Plugin)}
-     */
-    @Deprecated(forRemoval = true, since = "4.2.0")
-    default void releasePlayer(@NotNull Player player, @NotNull Plugin plugin) {}
-
-    /**
-     * @deprecated OpenInv no longer uses an internal cache beyond maintaining copies of currently open inventories.
-     * If you wish to use/modify a player, ensure either {@link IOpenInv#isPlayerLoaded(UUID)} is false or the player
-     * instance is the same memory address as the one in use by OpenInv.
-     * <pre>
-     *  public &#64;NotNull Player savePlayerData(&#64;NotNull Player player) {
-     *     IOpenInv openInv = ...
-     *     if (!openInv.disableSaving() && openInv.isPlayerLoaded(player.getUniqueId())) {
-     *         Player openInvLoadedPlayer = openInv.loadPlayer(myInUsePlayer);
-     *         if (openInvLoadedPlayer != player) {
-     *             // The copy loaded by OpenInv is not the same as our loaded copy. Push our changes.
-     *             copyPlayerModifications(player, openInvLoadedPlayer);
-     *         }
-     *         // OpenInv will handle saving data when the player is unloaded.
-     *         // Optionally, to be sure our changes will persist, save now.
-     *         // openInvLoadedPlayer.saveData();
-     *         return openInvLoadedPlayer;
-     *     }
-     *
-     *     player.saveData();
-     *     return player;
-     * }
-     * </pre>
-     */
-    @Deprecated(forRemoval = true, since = "4.2.0")
-    default void retainPlayer(@NotNull Player player, @NotNull Plugin plugin) {}
-
     /**
      * Forcibly close inventories of and unload any cached data for a user.
      *
diff --git a/api/src/main/java/com/lishid/openinv/event/OpenPlayerSaveEvent.java b/api/src/main/java/com/lishid/openinv/event/OpenPlayerSaveEvent.java
index a36a6c96..f20c635a 100644
--- a/api/src/main/java/com/lishid/openinv/event/OpenPlayerSaveEvent.java
+++ b/api/src/main/java/com/lishid/openinv/event/OpenPlayerSaveEvent.java
@@ -1,35 +1,34 @@
 package com.lishid.openinv.event;
 
+import com.google.errorprone.annotations.RestrictedApi;
 import com.lishid.openinv.internal.ISpecialInventory;
 import org.bukkit.entity.Player;
-import org.bukkit.event.Cancellable;
-import org.bukkit.event.Event;
-import org.bukkit.event.HandlerList;
+import org.jetbrains.annotations.ApiStatus;
 import org.jetbrains.annotations.NotNull;
 
 /**
- * Event fired before OpenInv saves a player's data.
+ * Event fired before OpenInv saves a player's data when closing an {@link ISpecialInventory}.
  */
-public class OpenPlayerSaveEvent extends Event implements Cancellable {
+public class OpenPlayerSaveEvent extends PlayerSaveEvent {
 
-  private static final HandlerList HANDLERS = new HandlerList();
-
-  private final Player player;
   private final ISpecialInventory inventory;
-  private boolean cancelled = false;
-
-  public OpenPlayerSaveEvent(@NotNull Player player, @NotNull ISpecialInventory inventory) {
-    this.player = player;
-    this.inventory = inventory;
-  }
 
   /**
-   * Get the {@link Player} whose data is being saved.
+   * Construct a new {@code OpenPlayerSaveEvent}.
+   *
+   * <p>The constructor is not considered part of the API, and may be subject to change.</p>
    *
-   * @return player the Player whose data is being saved
+   * @param player the player to be saved
+   * @param inventory the {@link ISpecialInventory} being closed
    */
-  public @NotNull Player getPlayer() {
-    return player;
+  @RestrictedApi(
+      explanation = "Constructor is not considered part of the API and may be subject to change.",
+      link = "",
+      allowedOnPath = ".*/com/lishid/openinv/event/OpenEvents.java")
+  @ApiStatus.Internal
+  OpenPlayerSaveEvent(@NotNull Player player, @NotNull ISpecialInventory inventory) {
+    super(player);
+    this.inventory = inventory;
   }
 
   /**
@@ -41,34 +40,4 @@ public OpenPlayerSaveEvent(@NotNull Player player, @NotNull ISpecialInventory in
     return inventory;
   }
 
-  /**
-   * Get whether the event is cancelled.
-   *
-   * @return true if the event is cancelled
-   */
-  @Override
-  public boolean isCancelled() {
-    return cancelled;
-  }
-
-  /**
-   * Set whether the event is cancelled.
-   *
-   * @param cancel whether the event is cancelled
-   */
-  @Override
-  public void setCancelled(boolean cancel) {
-    this.cancelled = cancel;
-  }
-
-  @NotNull
-  @Override
-  public HandlerList getHandlers() {
-    return HANDLERS;
-  }
-
-  public static HandlerList getHandlerList() {
-    return HANDLERS;
-  }
-
 }
diff --git a/api/src/main/java/com/lishid/openinv/event/PlayerSaveEvent.java b/api/src/main/java/com/lishid/openinv/event/PlayerSaveEvent.java
new file mode 100644
index 00000000..4ca1d715
--- /dev/null
+++ b/api/src/main/java/com/lishid/openinv/event/PlayerSaveEvent.java
@@ -0,0 +1,67 @@
+package com.lishid.openinv.event;
+
+
+import com.google.errorprone.annotations.RestrictedApi;
+import org.bukkit.entity.Player;
+import org.bukkit.event.Cancellable;
+import org.bukkit.event.HandlerList;
+import org.bukkit.event.player.PlayerEvent;
+import org.jetbrains.annotations.ApiStatus;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Event fired before a {@link Player} loaded via OpenInv is saved.
+ */
+public class PlayerSaveEvent extends PlayerEvent implements Cancellable {
+
+  private static final HandlerList HANDLERS = new HandlerList();
+
+  private boolean cancelled = false;
+
+  /**
+   * Construct a new {@code PlayerSaveEvent}.
+   *
+   * <p>The constructor is not considered part of the API, and may be subject to change.</p>
+   *
+   * @param player the player to be saved
+   */
+  @RestrictedApi(
+      explanation = "Constructor is not considered part of the API and may be subject to change.",
+      link = "",
+      allowedOnPath = ".*/com/lishid/openinv/event/(OpenPlayerSaveEvent|OpenEvents).java")
+  @ApiStatus.Internal
+  PlayerSaveEvent(@NotNull Player player) {
+    super(player);
+  }
+
+  /**
+   * Get whether the event is cancelled.
+   *
+   * @return true if the event is cancelled
+   */
+  @Override
+  public boolean isCancelled() {
+    return cancelled;
+  }
+
+  /**
+   * Set whether the event is cancelled.
+   *
+   * @param cancel whether the event is cancelled
+   */
+  @Override
+  public void setCancelled(boolean cancel) {
+    this.cancelled = cancel;
+  }
+
+  @NotNull
+  @Override
+  public HandlerList getHandlers() {
+    return HANDLERS;
+  }
+
+  public static HandlerList getHandlerList() {
+    return HANDLERS;
+  }
+
+}
diff --git a/api/src/main/java/com/lishid/openinv/internal/IAnySilentContainer.java b/api/src/main/java/com/lishid/openinv/internal/IAnySilentContainer.java
index 99026bc3..d4bccb91 100644
--- a/api/src/main/java/com/lishid/openinv/internal/IAnySilentContainer.java
+++ b/api/src/main/java/com/lishid/openinv/internal/IAnySilentContainer.java
@@ -51,17 +51,6 @@ public interface IAnySilentContainer {
      */
     void deactivateContainer(@NotNull Player player);
 
-    /**
-     * @param player the player opening the container
-     * @param block  the {@link Block} of the container
-     * @return true if the container is blocked
-     * @deprecated use {@link #isAnyContainerNeeded(Block)}
-     */
-    @Deprecated(forRemoval = true, since = "4.1.9")
-    default boolean isAnyContainerNeeded(@NotNull Player player, @NotNull Block block) {
-        return isAnyContainerNeeded(block);
-    }
-
     /**
      * Check if the container at the given coordinates is blocked.
      *
@@ -99,9 +88,14 @@ default boolean isAnyContainerNeeded(@NotNull Block block) {
             return false;
         }
 
-        int ordinal = (chest.getFacing().ordinal() + 4 + (chest.getType() == Chest.Type.RIGHT ? -1 : 1)) % 4;
-        BlockFace relativeFace = BlockFace.values()[ordinal];
-        org.bukkit.block.Block relative = block.getRelative(relativeFace);
+        BlockFace relativeFace = switch (chest.getFacing()) {
+            case NORTH -> chest.getType() == Chest.Type.RIGHT ? BlockFace.WEST : BlockFace.EAST;
+            case EAST -> chest.getType() == Chest.Type.RIGHT ? BlockFace.NORTH : BlockFace.SOUTH;
+            case SOUTH -> chest.getType() == Chest.Type.RIGHT ? BlockFace.EAST : BlockFace.WEST;
+            case WEST -> chest.getType() == Chest.Type.RIGHT ? BlockFace.SOUTH : BlockFace.NORTH;
+            default -> BlockFace.SELF;
+        };
+        Block relative = block.getRelative(relativeFace);
 
         if (relative.getType() != block.getType()) {
             return false;
@@ -120,18 +114,6 @@ default boolean isAnyContainerNeeded(@NotNull Block block) {
         return isChestBlocked(relative);
     }
 
-    /**
-     * Check if a {@link ShulkerBox} cannot be opened under ordinary circumstances.
-     *
-     * @deprecated Use {@link #isShulkerBlocked(Block)}.
-     * @param shulkerBox the shulker box container
-     * @return whether the container is blocked
-     */
-    @Deprecated(since = "4.4.4", forRemoval = true)
-    default boolean isShulkerBlocked(@NotNull ShulkerBox shulkerBox) {
-        return isShulkerBlocked(shulkerBox.getBlock());
-    }
-
     /**
      * Check if a shulker box block cannot be opened under ordinary circumstances.
      *
@@ -176,7 +158,7 @@ default boolean isAnySilentContainer(@NotNull Block block) {
      * @return true if the type is a supported container
      */
     default boolean isAnySilentContainer(@NotNull BlockState blockState) {
-        return blockState instanceof InventoryHolder holder && isAnySilentContainer(holder)
+        return (blockState instanceof InventoryHolder holder && isAnySilentContainer(holder))
                 || blockState instanceof EnderChest;
     }
 
diff --git a/api/src/main/java/com/lishid/openinv/internal/IInventoryAccess.java b/api/src/main/java/com/lishid/openinv/internal/IInventoryAccess.java
deleted file mode 100644
index 7f29a070..00000000
--- a/api/src/main/java/com/lishid/openinv/internal/IInventoryAccess.java
+++ /dev/null
@@ -1,62 +0,0 @@
-/*
- * Copyright (C) 2011-2022 lishid. All rights reserved.
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, version 3.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program. If not, see <http://www.gnu.org/licenses/>.
- */
-
-package com.lishid.openinv.internal;
-
-import com.lishid.openinv.util.InventoryAccess;
-import org.bukkit.inventory.Inventory;
-import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
-
-/**
- * @deprecated Use static {@link InventoryAccess} methods.
- */
-@Deprecated(forRemoval = true)
-public interface IInventoryAccess {
-
-    /**
-     * @deprecated Use static {@link InventoryAccess} methods.
-     */
-    @Deprecated(forRemoval = true)
-    default @Nullable ISpecialEnderChest getSpecialEnderChest(@NotNull Inventory inventory) {
-        return InventoryAccess.getEnderChest(inventory);
-    }
-
-    /**
-     * @deprecated Use static {@link InventoryAccess} methods.
-     */
-    @Deprecated(forRemoval = true)
-    default @Nullable ISpecialPlayerInventory getSpecialPlayerInventory(@NotNull Inventory inventory) {
-        return InventoryAccess.getPlayerInventory(inventory);
-    }
-
-    /**
-     * @deprecated Use static {@link InventoryAccess} methods.
-     */
-    @Deprecated(forRemoval = true)
-    default boolean isSpecialEnderChest(@NotNull Inventory inventory) {
-        return InventoryAccess.isEnderChest(inventory);
-    }
-
-    /**
-     * @deprecated Use static {@link InventoryAccess} methods.
-     */
-    @Deprecated(forRemoval = true)
-    default boolean isSpecialPlayerInventory(@NotNull Inventory inventory) {
-        return InventoryAccess.isPlayerInventory(inventory);
-    }
-
-}
diff --git a/api/src/main/java/com/lishid/openinv/util/InventoryAccess.java b/api/src/main/java/com/lishid/openinv/util/InventoryAccess.java
index e05bbe1e..466cae61 100644
--- a/api/src/main/java/com/lishid/openinv/util/InventoryAccess.java
+++ b/api/src/main/java/com/lishid/openinv/util/InventoryAccess.java
@@ -16,40 +16,23 @@
 
 package com.lishid.openinv.util;
 
-import com.lishid.openinv.internal.IInventoryAccess;
+import com.google.errorprone.annotations.RestrictedApi;
 import com.lishid.openinv.internal.ISpecialEnderChest;
 import com.lishid.openinv.internal.ISpecialInventory;
 import com.lishid.openinv.internal.ISpecialPlayerInventory;
-import org.bukkit.Bukkit;
 import org.bukkit.inventory.Inventory;
+import org.jetbrains.annotations.ApiStatus;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
-import java.lang.reflect.Method;
+import java.util.function.BiFunction;
 
-public final class InventoryAccess implements IInventoryAccess {
+public final class InventoryAccess {
 
-    private static Class<?> craftInventory = null;
-    private static Method getInventory = null;
-
-    static {
-        String packageName = Bukkit.getServer().getClass().getPackage().getName();
-        try {
-            craftInventory = Class.forName(packageName + ".inventory.CraftInventory");
-            getInventory = craftInventory.getDeclaredMethod("getInventory");
-        } catch (ClassNotFoundException | NoSuchMethodException ignored) {}
-    }
-
-    /**
-     * @deprecated use {@link #isUsable()}
-     */
-    @Deprecated(forRemoval = true)
-    public static boolean isUseable() {
-        return isUsable();
-    }
+    private static @Nullable BiFunction<Inventory, Class<? extends ISpecialInventory>, ISpecialInventory> provider;
 
     public static boolean isUsable() {
-        return craftInventory != null && getInventory != null;
+        return provider != null;
     }
 
     /**
@@ -70,7 +53,7 @@ public static boolean isPlayerInventory(@NotNull Inventory inventory) {
      * @return the backing implementation if available
      */
     public static @Nullable ISpecialPlayerInventory getPlayerInventory(@NotNull Inventory inventory) {
-        return getSpecialInventory(ISpecialPlayerInventory.class, inventory);
+        return provider == null ? null : (ISpecialPlayerInventory) provider.apply(inventory, ISpecialPlayerInventory.class);
     }
 
     /**
@@ -91,7 +74,7 @@ public static boolean isEnderChest(@NotNull Inventory inventory) {
      * @return the backing implementation if available
      */
     public static @Nullable ISpecialEnderChest getEnderChest(@NotNull Inventory inventory) {
-        return getSpecialInventory(ISpecialEnderChest.class, inventory);
+        return provider == null ? null : (ISpecialEnderChest) provider.apply(inventory, ISpecialEnderChest.class);
     }
 
     /**
@@ -102,34 +85,20 @@ public static boolean isEnderChest(@NotNull Inventory inventory) {
      * @return the backing implementation if available
      */
     public static @Nullable ISpecialInventory getInventory(@NotNull Inventory inventory) {
-        return getSpecialInventory(ISpecialInventory.class, inventory);
+        return provider == null ? null : provider.apply(inventory, ISpecialInventory.class);
     }
 
-    private static <T extends ISpecialInventory> @Nullable T getSpecialInventory(@NotNull Class<T> expected, @NotNull Inventory inventory) {
-        Object inv;
-        if (isUsable() && craftInventory.isAssignableFrom(inventory.getClass())) {
-            try {
-                inv = getInventory.invoke(inventory);
-                if (expected.isInstance(inv)) {
-                    return expected.cast(inv);
-                }
-            } catch (ReflectiveOperationException ignored) {}
-        }
-
-        // Use reflection to find the IInventory
-        inv = ReflectionHelper.grabObjectByType(inventory, expected);
-
-        if (expected.isInstance(inv)) {
-            return expected.cast(inv);
-        }
-
-        return null;
+    @RestrictedApi(
+        explanation = "Not part of the API.",
+        link = "",
+        allowedOnPath = ".*/com/lishid/openinv/util/InternalAccessor.java")
+    @ApiStatus.Internal
+    static void setProvider(@Nullable BiFunction<Inventory, Class<? extends ISpecialInventory>, ISpecialInventory> provider) {
+        InventoryAccess.provider = provider;
     }
 
-    /**
-     * @deprecated Do not create a new instance to use static methods.
-     */
-    @Deprecated(forRemoval = true, since = "4.2.0")
-    public InventoryAccess() {}
+    private InventoryAccess() {
+        throw new IllegalStateException("Cannot create instance of utility class.");
+    }
 
 }
diff --git a/assembly/pom.xml b/assembly/pom.xml
deleted file mode 100644
index 3fd0775e..00000000
--- a/assembly/pom.xml
+++ /dev/null
@@ -1,58 +0,0 @@
-<!--
-  ~ Copyright (C) 2011-2022 lishid. All rights reserved.
-  ~
-  ~ This program is free software: you can redistribute it and/or modify
-  ~ it under the terms of the GNU General Public License as published by
-  ~ the Free Software Foundation, version 3.
-  ~
-  ~ This program is distributed in the hope that it will be useful,
-  ~ but WITHOUT ANY WARRANTY; without even the implied warranty of
-  ~ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-  ~ GNU General Public License for more details.
-  ~
-  ~ You should have received a copy of the GNU General Public License
-  ~ along with this program. If not, see <http://www.gnu.org/licenses/>.
-  -->
-
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
-  <modelVersion>4.0.0</modelVersion>
-
-  <parent>
-    <groupId>com.lishid</groupId>
-    <artifactId>openinvparent</artifactId>
-    <version>5.0.0-SNAPSHOT</version>
-  </parent>
-
-  <artifactId>openinvassembly</artifactId>
-  <name>OpenInvAssembly</name>
-  <packaging>pom</packaging>
-
-  <build>
-    <directory>../target</directory>
-    <finalName>OpenInv</finalName>
-
-    <plugins>
-      <plugin>
-        <artifactId>maven-assembly-plugin</artifactId>
-        <executions>
-          <execution>
-            <id>reactor-uberjar</id>
-            <phase>package</phase>
-            <goals>
-              <goal>single</goal>
-            </goals>
-            <configuration>
-              <appendAssemblyId>false</appendAssemblyId>
-              <descriptors>
-                <descriptor>src/assembly/reactor-uberjar.xml</descriptor>
-              </descriptors>
-            </configuration>
-          </execution>
-        </executions>
-      </plugin>
-    </plugins>
-
-  </build>
-
-</project>
diff --git a/assembly/src/assembly/reactor-uberjar.xml b/assembly/src/assembly/reactor-uberjar.xml
deleted file mode 100644
index cb400f35..00000000
--- a/assembly/src/assembly/reactor-uberjar.xml
+++ /dev/null
@@ -1,54 +0,0 @@
-<!--
-  ~ Copyright (C) 2011-2021 lishid. All rights reserved.
-  ~
-  ~ This program is free software: you can redistribute it and/or modify
-  ~ it under the terms of the GNU General Public License as published by
-  ~ the Free Software Foundation, version 3.
-  ~
-  ~ This program is distributed in the hope that it will be useful,
-  ~ but WITHOUT ANY WARRANTY; without even the implied warranty of
-  ~ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-  ~ GNU General Public License for more details.
-  ~
-  ~ You should have received a copy of the GNU General Public License
-  ~ along with this program. If not, see <http://www.gnu.org/licenses/>.
-  -->
-
-<assembly xmlns="http://maven.apache.org/ASSEMBLY/2.1.0"
-    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-    xsi:schemaLocation="http://maven.apache.org/ASSEMBLY/2.1.0 http://maven.apache.org/xsd/assembly-2.1.0.xsd">
-
-  <id>reactor-uberjar</id>
-
-  <formats>
-    <format>jar</format>
-  </formats>
-
-  <includeBaseDirectory>false</includeBaseDirectory>
-
-  <moduleSets>
-    <moduleSet>
-
-      <useAllReactorProjects>true</useAllReactorProjects>
-
-      <binaries>
-        <outputDirectory>/</outputDirectory>
-        <unpack>true</unpack>
-        <unpackOptions>
-          <excludes>
-            <!--
-              - Exclude existing meta - assembly will write its own manifest, and the rest is maven
-              - details that end users don't need. Ignoring it saves around 7KB after compression
-              - with a single internal module present.
-             -->
-            <exclude>META-INF/**</exclude>
-          </excludes>
-        </unpackOptions>
-        <!-- Exclude dependencies - shade plugin will handle their inclusion as necessary in individual jars. -->
-        <includeDependencies>false</includeDependencies>
-      </binaries>
-
-    </moduleSet>
-  </moduleSets>
-
-</assembly>
diff --git a/common/pom.xml b/common/pom.xml
new file mode 100644
index 00000000..09389665
--- /dev/null
+++ b/common/pom.xml
@@ -0,0 +1,30 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <parent>
+        <groupId>com.lishid</groupId>
+        <artifactId>openinvparent</artifactId>
+        <version>5.0.0-SNAPSHOT</version>
+    </parent>
+
+    <artifactId>openinvcommon</artifactId>
+
+    <dependencies>
+        <dependency>
+            <artifactId>annotations</artifactId>
+            <groupId>org.jetbrains</groupId>
+        </dependency>
+        <dependency>
+            <groupId>org.spigotmc</groupId>
+            <artifactId>spigot-api</artifactId>
+        </dependency>
+        <dependency>
+            <artifactId>openinvapi</artifactId>
+            <groupId>com.lishid</groupId>
+        </dependency>
+    </dependencies>
+
+</project>
diff --git a/common/src/main/java/com/lishid/openinv/event/OpenEvents.java b/common/src/main/java/com/lishid/openinv/event/OpenEvents.java
new file mode 100644
index 00000000..77349ccf
--- /dev/null
+++ b/common/src/main/java/com/lishid/openinv/event/OpenEvents.java
@@ -0,0 +1,32 @@
+package com.lishid.openinv.event;
+
+import com.lishid.openinv.internal.ISpecialInventory;
+import org.bukkit.Bukkit;
+import org.bukkit.entity.Player;
+import org.bukkit.event.Cancellable;
+import org.bukkit.event.Event;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Construct and call events.
+ */
+public final class OpenEvents {
+
+  public static boolean saveCancelled(@NotNull Player player) {
+    return call(new PlayerSaveEvent(player));
+  }
+
+  public static boolean saveCancelled(@NotNull Player player, @NotNull ISpecialInventory inventory) {
+    return call(new OpenPlayerSaveEvent(player, inventory));
+  }
+
+  private static <T extends Event & Cancellable> boolean call(T event) {
+    Bukkit.getPluginManager().callEvent(event);
+    return event.isCancelled();
+  }
+
+  private OpenEvents() {
+    throw new IllegalStateException("Cannot create instance of utility class.");
+  }
+
+}
diff --git a/common/src/main/java/com/lishid/openinv/internal/Accessor.java b/common/src/main/java/com/lishid/openinv/internal/Accessor.java
new file mode 100644
index 00000000..e57a4afb
--- /dev/null
+++ b/common/src/main/java/com/lishid/openinv/internal/Accessor.java
@@ -0,0 +1,24 @@
+package com.lishid.openinv.internal;
+
+import org.bukkit.configuration.ConfigurationSection;
+import org.bukkit.entity.Player;
+import org.bukkit.inventory.Inventory;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+public interface Accessor {
+
+  @NotNull
+  PlayerManager getPlayerManager();
+
+  @NotNull IAnySilentContainer getAnySilentContainer();
+
+  @NotNull ISpecialPlayerInventory createPlayerInventory(@NotNull Player player);
+
+  @NotNull ISpecialEnderChest createEnderChest(@NotNull Player player);
+
+  <T extends ISpecialInventory> @Nullable T get(@NotNull Inventory bukkitInventory, @NotNull Class<T> clazz);
+
+  void reload(@NotNull ConfigurationSection config);
+
+}
diff --git a/plugin/src/main/java/com/lishid/openinv/internal/InventoryViewTitle.java b/common/src/main/java/com/lishid/openinv/internal/InventoryViewTitle.java
similarity index 82%
rename from plugin/src/main/java/com/lishid/openinv/internal/InventoryViewTitle.java
rename to common/src/main/java/com/lishid/openinv/internal/InventoryViewTitle.java
index 7bff29a1..ccd8fd13 100644
--- a/plugin/src/main/java/com/lishid/openinv/internal/InventoryViewTitle.java
+++ b/common/src/main/java/com/lishid/openinv/internal/InventoryViewTitle.java
@@ -1,6 +1,6 @@
 package com.lishid.openinv.internal;
 
-import com.lishid.openinv.OpenInv;
+import com.lishid.openinv.util.lang.LanguageManager;
 import com.lishid.openinv.util.lang.Replacement;
 import org.bukkit.entity.HumanEntity;
 import org.bukkit.entity.Player;
@@ -22,11 +22,13 @@ public enum InventoryViewTitle {
     this.defaultSuffix = defaultSuffix;
   }
 
-  public @NotNull String getTitle(@NotNull Player viewer, @NotNull ISpecialInventory inventory) {
+  public @NotNull String getTitle(
+      @NotNull LanguageManager lang,
+      @NotNull Player viewer,
+      @NotNull ISpecialInventory inventory) {
     HumanEntity owner = inventory.getPlayer();
 
-    String localTitle = OpenInv.getPlugin(OpenInv.class)
-        .getLocalizedMessage(
+    String localTitle = lang.getLocalizedMessage(
             viewer,
             localizationKey,
             new Replacement("%player%", owner.getName()));
diff --git a/plugin/src/main/java/com/lishid/openinv/internal/OpenInventoryView.java b/common/src/main/java/com/lishid/openinv/internal/OpenInventoryView.java
similarity index 100%
rename from plugin/src/main/java/com/lishid/openinv/internal/OpenInventoryView.java
rename to common/src/main/java/com/lishid/openinv/internal/OpenInventoryView.java
diff --git a/plugin/src/main/java/com/lishid/openinv/internal/PlaceholderParser.java b/common/src/main/java/com/lishid/openinv/internal/PlaceholderParser.java
similarity index 100%
rename from plugin/src/main/java/com/lishid/openinv/internal/PlaceholderParser.java
rename to common/src/main/java/com/lishid/openinv/internal/PlaceholderParser.java
diff --git a/plugin/src/main/java/com/lishid/openinv/internal/IPlayerDataManager.java b/common/src/main/java/com/lishid/openinv/internal/PlayerManager.java
similarity index 97%
rename from plugin/src/main/java/com/lishid/openinv/internal/IPlayerDataManager.java
rename to common/src/main/java/com/lishid/openinv/internal/PlayerManager.java
index 37bb1bf0..d1d3c6c0 100644
--- a/plugin/src/main/java/com/lishid/openinv/internal/IPlayerDataManager.java
+++ b/common/src/main/java/com/lishid/openinv/internal/PlayerManager.java
@@ -22,7 +22,7 @@
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
-public interface IPlayerDataManager {
+public interface PlayerManager {
 
     /**
      * Loads a Player for an OfflinePlayer.
diff --git a/plugin/src/main/java/com/lishid/openinv/util/Permissions.java b/common/src/main/java/com/lishid/openinv/util/Permissions.java
similarity index 100%
rename from plugin/src/main/java/com/lishid/openinv/util/Permissions.java
rename to common/src/main/java/com/lishid/openinv/util/Permissions.java
diff --git a/api/src/main/java/com/lishid/openinv/util/ReflectionHelper.java b/common/src/main/java/com/lishid/openinv/util/ReflectionHelper.java
similarity index 93%
rename from api/src/main/java/com/lishid/openinv/util/ReflectionHelper.java
rename to common/src/main/java/com/lishid/openinv/util/ReflectionHelper.java
index 7c283749..2c60ffe0 100644
--- a/api/src/main/java/com/lishid/openinv/util/ReflectionHelper.java
+++ b/common/src/main/java/com/lishid/openinv/util/ReflectionHelper.java
@@ -16,16 +16,15 @@
 
 package com.lishid.openinv.util;
 
-import java.lang.reflect.Field;
 import org.jetbrains.annotations.Nullable;
 
+import java.lang.reflect.Field;
+
 /**
  * A utility for making reflection easier.
  */
 public final class ReflectionHelper {
 
-    private ReflectionHelper() {}
-
     /**
      * Grab an {@link Object} stored in a {@link Field} of another {@code Object}.
      *
@@ -59,8 +58,8 @@ private ReflectionHelper() {}
      */
     public static @Nullable Field grabFieldByType(Class<?> holderType, Class<?> fieldType) {
         for (Field field : holderType.getDeclaredFields()) {
-            field.setAccessible(true);
             if (fieldType.isAssignableFrom(field.getType())) {
+                field.setAccessible(true);
                 return field;
             }
         }
@@ -72,4 +71,8 @@ private ReflectionHelper() {}
         return null;
     }
 
+    private ReflectionHelper() {
+        throw new IllegalStateException("Cannot create instance of utility class.");
+    }
+
 }
diff --git a/plugin/src/main/java/com/lishid/openinv/util/lang/LanguageManager.java b/common/src/main/java/com/lishid/openinv/util/lang/LanguageManager.java
similarity index 79%
rename from plugin/src/main/java/com/lishid/openinv/util/lang/LanguageManager.java
rename to common/src/main/java/com/lishid/openinv/util/lang/LanguageManager.java
index 4438977b..6e5fe207 100644
--- a/plugin/src/main/java/com/lishid/openinv/util/lang/LanguageManager.java
+++ b/common/src/main/java/com/lishid/openinv/util/lang/LanguageManager.java
@@ -16,7 +16,18 @@
 
 package com.lishid.openinv.util.lang;
 
-import com.lishid.openinv.OpenInv;
+import net.md_5.bungee.api.ChatMessageType;
+import net.md_5.bungee.api.chat.TextComponent;
+import org.bukkit.ChatColor;
+import org.bukkit.command.CommandSender;
+import org.bukkit.configuration.Configuration;
+import org.bukkit.configuration.ConfigurationSection;
+import org.bukkit.configuration.file.YamlConfiguration;
+import org.bukkit.entity.Player;
+import org.bukkit.plugin.Plugin;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
 import java.io.BufferedReader;
 import java.io.File;
 import java.io.IOException;
@@ -26,15 +37,10 @@
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import java.util.function.Predicate;
 import java.util.logging.Level;
-import org.bukkit.ChatColor;
-import org.bukkit.configuration.Configuration;
-import org.bukkit.configuration.ConfigurationSection;
-import org.bukkit.configuration.file.YamlConfiguration;
-import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
 
 /**
  * A simple language manager supporting both custom and bundled languages.
@@ -43,11 +49,11 @@
  */
 public class LanguageManager {
 
-    private final OpenInv plugin;
+    private final Plugin plugin;
     private final String defaultLocale;
     private final Map<String, YamlConfiguration> locales;
 
-    public LanguageManager(@NotNull OpenInv plugin, @NotNull String defaultLocale) {
+    public LanguageManager(@NotNull Plugin plugin, @NotNull String defaultLocale) {
         this.plugin = plugin;
         this.defaultLocale = defaultLocale;
         this.locales = new HashMap<>();
@@ -191,7 +197,7 @@ private void addTranslationFallthrough(
     }
 
     public @Nullable String getValue(@NotNull String key, @Nullable String locale) {
-        String value = getOrLoadLocale(locale == null ? defaultLocale : locale.toLowerCase()).getString(key);
+        String value = getOrLoadLocale(locale == null ? defaultLocale : locale.toLowerCase(Locale.ROOT)).getString(key);
         if (value == null || value.isEmpty()) {
             return null;
         }
@@ -215,4 +221,59 @@ private void addTranslationFallthrough(
         return value;
     }
 
+    public @Nullable String getLocalizedMessage(@NotNull CommandSender sender, @NotNull String key) {
+        return getValue(key, getLocale(sender));
+    }
+
+    public @Nullable String getLocalizedMessage(
+        @NotNull CommandSender sender,
+        @NotNull String key,
+        Replacement @NotNull ... replacements) {
+        return getValue(key, getLocale(sender), replacements);
+    }
+
+    private @NotNull String getLocale(@NotNull CommandSender sender) {
+        if (sender instanceof Player) {
+            return ((Player) sender).getLocale();
+        } else {
+            return plugin.getConfig().getString("settings.locale", "en_us");
+        }
+    }
+
+    public void sendMessage(@NotNull CommandSender sender, @NotNull String key) {
+        String message = getLocalizedMessage(sender, key);
+
+        if (message != null && !message.isEmpty()) {
+            sender.sendMessage(message);
+        }
+    }
+
+    public void sendMessage(@NotNull CommandSender sender, @NotNull String key, Replacement @NotNull... replacements) {
+        String message = getLocalizedMessage(sender, key, replacements);
+
+        if (message != null && !message.isEmpty()) {
+            sender.sendMessage(message);
+        }
+    }
+
+    public void sendSystemMessage(@NotNull Player player, @NotNull String key) {
+        String message = getLocalizedMessage(player, key);
+
+        if (message == null) {
+            return;
+        }
+
+        int newline = message.indexOf('\n');
+        if (newline != -1) {
+            // No newlines in action bar chat.
+            message = message.substring(0, newline);
+        }
+
+        if (message.isEmpty()) {
+            return;
+        }
+
+        player.spigot().sendMessage(ChatMessageType.ACTION_BAR, TextComponent.fromLegacy(message));
+    }
+
 }
diff --git a/plugin/src/main/java/com/lishid/openinv/util/lang/Replacement.java b/common/src/main/java/com/lishid/openinv/util/lang/Replacement.java
similarity index 100%
rename from plugin/src/main/java/com/lishid/openinv/util/lang/Replacement.java
rename to common/src/main/java/com/lishid/openinv/util/lang/Replacement.java
diff --git a/internal/v1_20_R3/pom.xml b/internal/v1_20_R3/pom.xml
index be4bb10b..53508df9 100644
--- a/internal/v1_20_R3/pom.xml
+++ b/internal/v1_20_R3/pom.xml
@@ -30,8 +30,8 @@
   <name>OpenInvAdapter1_20_R3</name>
 
   <properties>
-    <maven.compiler.source>17</maven.compiler.source>
-    <maven.compiler.target>17</maven.compiler.target>
+    <maven.compiler.system>17</maven.compiler.system>
+    <maven.compiler.release>17</maven.compiler.release>
     <spigot.version>1.20.4-R0.1-SNAPSHOT</spigot.version>
   </properties>
 
@@ -51,10 +51,9 @@
     <dependency>
       <artifactId>openinvapi</artifactId>
       <groupId>com.lishid</groupId>
-      <scope>provided</scope>
     </dependency>
     <dependency>
-      <artifactId>openinvplugincore</artifactId>
+      <artifactId>openinvcommon</artifactId>
       <groupId>com.lishid</groupId>
     </dependency>
     <dependency>
@@ -65,9 +64,6 @@
 
   <build>
     <plugins>
-      <plugin>
-        <artifactId>maven-shade-plugin</artifactId>
-      </plugin>
       <plugin>
         <artifactId>maven-compiler-plugin</artifactId>
       </plugin>
diff --git a/internal/v1_20_R3/src/main/java/com/lishid/openinv/internal/v1_20_R3/AnySilentContainer.java b/internal/v1_20_R3/src/main/java/com/lishid/openinv/internal/v1_20_R3/AnySilentContainer.java
index eb6d8fef..403b3ed8 100644
--- a/internal/v1_20_R3/src/main/java/com/lishid/openinv/internal/v1_20_R3/AnySilentContainer.java
+++ b/internal/v1_20_R3/src/main/java/com/lishid/openinv/internal/v1_20_R3/AnySilentContainer.java
@@ -16,9 +16,9 @@
 
 package com.lishid.openinv.internal.v1_20_R3;
 
-import com.lishid.openinv.OpenInv;
 import com.lishid.openinv.internal.IAnySilentContainer;
 import com.lishid.openinv.util.ReflectionHelper;
+import com.lishid.openinv.util.lang.LanguageManager;
 import net.minecraft.core.BlockPos;
 import net.minecraft.network.chat.Component;
 import net.minecraft.server.level.ServerPlayer;
@@ -50,15 +50,18 @@
 
 public class AnySilentContainer implements IAnySilentContainer {
 
+    private final @NotNull Logger logger;
+    private final @NotNull LanguageManager lang;
     private @Nullable Field serverPlayerGameModeGameType;
 
-    public AnySilentContainer() {
+    public AnySilentContainer(@NotNull Logger logger, @NotNull LanguageManager lang) {
+        this.logger = logger;
+        this.lang = lang;
         try {
             try {
                 this.serverPlayerGameModeGameType = ServerPlayerGameMode.class.getDeclaredField("b");
                 this.serverPlayerGameModeGameType.setAccessible(true);
             } catch (NoSuchFieldException e) {
-                Logger logger = OpenInv.getPlugin(OpenInv.class).getLogger();
                 logger.warning("ServerPlayerGameMode#gameModeForPlayer's obfuscated name has changed!");
                 logger.warning("Please report this at https://github.com/Jikoo/OpenInv/issues");
                 logger.warning("Attempting to fall through using reflection. Please verify that SilentContainer does not fail.");
@@ -66,7 +69,6 @@ public AnySilentContainer() {
                 this.serverPlayerGameModeGameType = ReflectionHelper.grabFieldByType(ServerPlayerGameMode.class, GameType.class);
             }
         } catch (SecurityException e) {
-            Logger logger = OpenInv.getPlugin(OpenInv.class).getLogger();
             logger.warning("Unable to directly write player game mode! SilentContainer will fail.");
             logger.log(java.util.logging.Level.WARNING, "Error obtaining GameType field", e);
         }
@@ -85,7 +87,7 @@ public boolean activateContainer(
             return true;
         }
 
-        ServerPlayer player = PlayerDataManager.getHandle(bukkitPlayer);
+        ServerPlayer player = PlayerManager.getHandle(bukkitPlayer);
 
         final net.minecraft.world.level.Level level = player.level();
         final BlockPos blockPos = new BlockPos(bukkitBlock.getX(), bukkitBlock.getY(), bukkitBlock.getZ());
@@ -100,10 +102,10 @@ public boolean activateContainer(
             PlayerEnderChestContainer enderChest = player.getEnderChestInventory();
             enderChest.setActiveChest(enderChestTile);
             player.openMenu(new SimpleMenuProvider((containerCounter, playerInventory, ignored) -> {
-                MenuType<?> containers = PlayerDataManager.getContainers(enderChest.getContainerSize());
+                MenuType<?> containers = PlayerManager.getContainers(enderChest.getContainerSize());
                 int rows = enderChest.getContainerSize() / 9;
                 return new ChestMenu(containers, containerCounter, playerInventory, enderChest, rows);
-            }, Component.translatable(("container.enderchest"))));
+            }, Component.translatable("container.enderchest")));
             bukkitPlayer.incrementStatistic(Statistic.ENDERCHEST_OPENED);
             return true;
         }
@@ -121,7 +123,7 @@ public boolean activateContainer(
             menuProvider = chestBlock.getMenuProvider(blockState, level, blockPos, true);
 
             if (menuProvider == null) {
-                OpenInv.getPlugin(OpenInv.class).sendSystemMessage(bukkitPlayer, "messages.error.lootNotGenerated");
+                lang.sendSystemMessage(bukkitPlayer, "messages.error.lootNotGenerated");
                 return false;
             }
 
@@ -153,7 +155,7 @@ public boolean activateContainer(
 
         if (blockEntity instanceof RandomizableContainerBlockEntity lootable) {
             if (lootable.lootTable != null) {
-                OpenInv.getPlugin(OpenInv.class).sendSystemMessage(bukkitPlayer, "messages.error.lootNotGenerated");
+                lang.sendSystemMessage(bukkitPlayer, "messages.error.lootNotGenerated");
                 return false;
             }
         }
@@ -171,7 +173,7 @@ public void deactivateContainer(@NotNull final Player bukkitPlayer) {
             return;
         }
 
-        ServerPlayer player = PlayerDataManager.getHandle(bukkitPlayer);
+        ServerPlayer player = PlayerManager.getHandle(bukkitPlayer);
 
         // Force game mode change without informing plugins or players.
         // Regular game mode set calls GameModeChangeEvent and is cancellable.
@@ -199,7 +201,6 @@ private void forceGameType(final ServerPlayer player, final GameType gameMode) {
             this.serverPlayerGameModeGameType.setAccessible(true);
             this.serverPlayerGameModeGameType.set(player.gameMode, gameMode);
         } catch (IllegalArgumentException | IllegalAccessException e) {
-            Logger logger = OpenInv.getPlugin(OpenInv.class).getLogger();
             logger.log(java.util.logging.Level.WARNING, "Error bypassing GameModeChangeEvent", e);
         }
     }
diff --git a/internal/v1_20_R3/src/main/java/com/lishid/openinv/internal/v1_20_R3/InternalAccessor.java b/internal/v1_20_R3/src/main/java/com/lishid/openinv/internal/v1_20_R3/InternalAccessor.java
new file mode 100644
index 00000000..47e199da
--- /dev/null
+++ b/internal/v1_20_R3/src/main/java/com/lishid/openinv/internal/v1_20_R3/InternalAccessor.java
@@ -0,0 +1,64 @@
+package com.lishid.openinv.internal.v1_20_R3;
+
+import com.lishid.openinv.internal.Accessor;
+import com.lishid.openinv.internal.IAnySilentContainer;
+import com.lishid.openinv.internal.ISpecialEnderChest;
+import com.lishid.openinv.internal.ISpecialInventory;
+import com.lishid.openinv.internal.ISpecialPlayerInventory;
+import com.lishid.openinv.util.lang.LanguageManager;
+import net.minecraft.world.Container;
+import org.bukkit.configuration.ConfigurationSection;
+import org.bukkit.craftbukkit.v1_20_R3.inventory.CraftInventory;
+import org.bukkit.entity.Player;
+import org.bukkit.inventory.Inventory;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.logging.Logger;
+
+public class InternalAccessor implements Accessor {
+
+  private final @NotNull PlayerManager manager;
+  private final @NotNull AnySilentContainer anySilentContainer;
+
+  public InternalAccessor(@NotNull Logger logger, @NotNull LanguageManager lang) {
+    manager = new PlayerManager(logger, lang);
+    anySilentContainer = new AnySilentContainer(logger, lang);
+  }
+
+  @Override
+  public @NotNull PlayerManager getPlayerManager() {
+    return manager;
+  }
+
+  @Override
+  public @NotNull IAnySilentContainer getAnySilentContainer() {
+    return anySilentContainer;
+  }
+
+  @Override
+  public @NotNull ISpecialPlayerInventory createPlayerInventory(@NotNull Player player) {
+    return new SpecialPlayerInventory(player, player.isOnline());
+  }
+
+  @Override
+  public @NotNull ISpecialEnderChest createEnderChest(@NotNull Player player) {
+    return new SpecialEnderChest(player, player.isOnline());
+  }
+
+  @Override
+  public <T extends ISpecialInventory> @Nullable T get(@NotNull Inventory bukkitInventory, @NotNull Class<T> clazz) {
+    if (!(bukkitInventory instanceof CraftInventory craftInventory)) {
+      return null;
+    }
+    Container container = craftInventory.getInventory();
+    if (clazz.isInstance(container)) {
+      return clazz.cast(container);
+    }
+    return null;
+  }
+
+  @Override
+  public void reload(@NotNull ConfigurationSection config) {}
+
+}
diff --git a/internal/v1_20_R3/src/main/java/com/lishid/openinv/internal/v1_20_R3/OpenPlayer.java b/internal/v1_20_R3/src/main/java/com/lishid/openinv/internal/v1_20_R3/OpenPlayer.java
index 2861c2bc..52d553af 100644
--- a/internal/v1_20_R3/src/main/java/com/lishid/openinv/internal/v1_20_R3/OpenPlayer.java
+++ b/internal/v1_20_R3/src/main/java/com/lishid/openinv/internal/v1_20_R3/OpenPlayer.java
@@ -16,6 +16,7 @@
 
 package com.lishid.openinv.internal.v1_20_R3;
 
+import com.lishid.openinv.event.OpenEvents;
 import com.mojang.logging.LogUtils;
 import net.minecraft.Util;
 import net.minecraft.nbt.CompoundTag;
@@ -70,17 +71,24 @@ public class OpenPlayer extends CraftPlayer {
         "Brain"
     );
 
-    public OpenPlayer(CraftServer server, ServerPlayer entity) {
+    private final PlayerManager manager;
+
+    OpenPlayer(CraftServer server, ServerPlayer entity, PlayerManager manager) {
         super(server, entity);
+        this.manager = manager;
     }
 
     @Override
     public void loadData() {
-        PlayerDataManager.loadData(getHandle());
+        manager.loadData(getHandle());
     }
 
     @Override
     public void saveData() {
+        if (OpenEvents.saveCancelled(this)) {
+            return;
+        }
+
         ServerPlayer player = this.getHandle();
         // See net.minecraft.world.level.storage.PlayerDataStorage#save(EntityHuman)
         try {
diff --git a/internal/v1_20_R3/src/main/java/com/lishid/openinv/internal/v1_20_R3/PlayerDataManager.java b/internal/v1_20_R3/src/main/java/com/lishid/openinv/internal/v1_20_R3/PlayerManager.java
similarity index 93%
rename from internal/v1_20_R3/src/main/java/com/lishid/openinv/internal/v1_20_R3/PlayerDataManager.java
rename to internal/v1_20_R3/src/main/java/com/lishid/openinv/internal/v1_20_R3/PlayerManager.java
index 17ed8e4e..7f02bb7d 100644
--- a/internal/v1_20_R3/src/main/java/com/lishid/openinv/internal/v1_20_R3/PlayerDataManager.java
+++ b/internal/v1_20_R3/src/main/java/com/lishid/openinv/internal/v1_20_R3/PlayerManager.java
@@ -16,11 +16,10 @@
 
 package com.lishid.openinv.internal.v1_20_R3;
 
-import com.lishid.openinv.OpenInv;
-import com.lishid.openinv.internal.IPlayerDataManager;
 import com.lishid.openinv.internal.ISpecialInventory;
 import com.lishid.openinv.internal.InventoryViewTitle;
 import com.lishid.openinv.internal.OpenInventoryView;
+import com.lishid.openinv.util.lang.LanguageManager;
 import com.mojang.authlib.GameProfile;
 import com.mojang.serialization.Dynamic;
 import net.minecraft.nbt.CompoundTag;
@@ -48,7 +47,6 @@
 import org.bukkit.craftbukkit.v1_20_R3.inventory.CraftContainer;
 import org.bukkit.entity.Player;
 import org.bukkit.inventory.InventoryView;
-import org.bukkit.plugin.java.JavaPlugin;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
@@ -56,7 +54,7 @@
 import java.util.UUID;
 import java.util.logging.Logger;
 
-public class PlayerDataManager implements IPlayerDataManager {
+public class PlayerManager implements com.lishid.openinv.internal.PlayerManager {
 
     private static boolean paper;
 
@@ -69,13 +67,16 @@ public class PlayerDataManager implements IPlayerDataManager {
         }
     }
 
+    private final @NotNull Logger logger;
+    private final @NotNull LanguageManager lang;
     private @Nullable Field bukkitEntity;
 
-    public PlayerDataManager() {
+    public PlayerManager(@NotNull Logger logger, @NotNull LanguageManager lang) {
+        this.logger = logger;
+        this.lang = lang;
         try {
             bukkitEntity = Entity.class.getDeclaredField("bukkitEntity");
         } catch (NoSuchFieldException e) {
-            Logger logger = JavaPlugin.getPlugin(OpenInv.class).getLogger();
             logger.warning("Unable to obtain field to inject custom save process - certain player data may be lost when saving!");
             logger.log(java.util.logging.Level.WARNING, e.getMessage(), e);
             bukkitEntity = null;
@@ -156,7 +157,7 @@ public PlayerDataManager() {
         try {
             injectPlayer(entity);
         } catch (IllegalAccessException e) {
-            JavaPlugin.getPlugin(OpenInv.class).getLogger().log(
+            logger.log(
                 java.util.logging.Level.WARNING,
                 e,
                 () -> "Unable to inject ServerPlayer, certain player data may be lost when saving!");
@@ -165,7 +166,7 @@ public PlayerDataManager() {
         return entity;
     }
 
-    static boolean loadData(@NotNull ServerPlayer player) {
+    boolean loadData(@NotNull ServerPlayer player) {
         // See CraftPlayer#loadData
         CompoundTag loadedData = player.server.getPlayerList().playerIo.load(player);
 
@@ -189,7 +190,7 @@ static boolean loadData(@NotNull ServerPlayer player) {
         return true;
     }
 
-    private static void parseWorld(@NotNull ServerPlayer player, @NotNull CompoundTag loadedData) {
+    private void parseWorld(@NotNull ServerPlayer player, @NotNull CompoundTag loadedData) {
         // See PlayerList#placeNewPlayer
         World bukkitWorld;
         if (loadedData.contains("WorldUUIDMost") && loadedData.contains("WorldUUIDLeast")) {
@@ -201,7 +202,7 @@ private static void parseWorld(@NotNull ServerPlayer player, @NotNull CompoundTa
         } else {
             // Vanilla player data.
             DimensionType.parseLegacy(new Dynamic<>(NbtOps.INSTANCE, loadedData.get("Dimension")))
-                .resultOrPartial(JavaPlugin.getPlugin(OpenInv.class).getLogger()::warning)
+                .resultOrPartial(logger::warning)
                 .map(player.server::getLevel)
                 // If ServerLevel exists, set, otherwise move to spawn.
                 .ifPresentOrElse(player::setServerLevel, () -> player.spawnIn(null));
@@ -221,7 +222,7 @@ private void injectPlayer(ServerPlayer player) throws IllegalAccessException {
 
         bukkitEntity.setAccessible(true);
 
-        bukkitEntity.set(player, new OpenPlayer(player.server.server, player));
+        bukkitEntity.set(player, new OpenPlayer(player.server.server, player, this));
     }
 
     @Override
@@ -234,7 +235,7 @@ private void injectPlayer(ServerPlayer player) throws IllegalAccessException {
             injectPlayer(nmsPlayer);
             return nmsPlayer.getBukkitEntity();
         } catch (IllegalAccessException e) {
-            JavaPlugin.getPlugin(OpenInv.class).getLogger().log(
+            logger.log(
                 java.util.logging.Level.WARNING,
                 e,
                 () -> "Unable to inject ServerPlayer, certain player data may be lost when saving!");
@@ -257,7 +258,7 @@ private void injectPlayer(ServerPlayer player) throws IllegalAccessException {
             return player.openInventory(inventory.getBukkitInventory());
         }
 
-        InventoryView view = new OpenInventoryView(player, inventory, title.getTitle(player, inventory));
+        InventoryView view = new OpenInventoryView(player, inventory, title.getTitle(lang, player, inventory));
         AbstractContainerMenu container = new CraftContainer(view, nmsPlayer, nmsPlayer.nextContainerCounter()) {
             @Override
             public MenuType<?> getType() {
diff --git a/internal/v1_20_R3/src/main/java/com/lishid/openinv/internal/v1_20_R3/SpecialEnderChest.java b/internal/v1_20_R3/src/main/java/com/lishid/openinv/internal/v1_20_R3/SpecialEnderChest.java
index 941e7979..2b8b3f38 100644
--- a/internal/v1_20_R3/src/main/java/com/lishid/openinv/internal/v1_20_R3/SpecialEnderChest.java
+++ b/internal/v1_20_R3/src/main/java/com/lishid/openinv/internal/v1_20_R3/SpecialEnderChest.java
@@ -49,9 +49,9 @@ public class SpecialEnderChest extends PlayerEnderChestContainer implements ISpe
     private boolean playerOnline;
 
     public SpecialEnderChest(final org.bukkit.entity.Player player, final Boolean online) {
-        super(PlayerDataManager.getHandle(player));
+        super(PlayerManager.getHandle(player));
         this.inventory = new CraftInventory(this);
-        this.owner = PlayerDataManager.getHandle(player);
+        this.owner = PlayerManager.getHandle(player);
         this.playerOnline = online;
         this.items = this.owner.getEnderChestInventory().items;
     }
@@ -73,7 +73,7 @@ public void setPlayerOnline(@NotNull final org.bukkit.entity.Player player) {
         }
 
         ServerPlayer offlinePlayer = this.owner;
-        ServerPlayer onlinePlayer = PlayerDataManager.getHandle(player);
+        ServerPlayer onlinePlayer = PlayerManager.getHandle(player);
 
         // Set owner to new player.
         this.owner = onlinePlayer;
@@ -198,7 +198,7 @@ public ItemStack addItem(ItemStack itemstack) {
     @Override
     public boolean canAddItem(ItemStack itemstack) {
         for (ItemStack itemstack1 : this.items) {
-            if (itemstack1.isEmpty() || ItemStack.isSameItemSameTags(itemstack1, itemstack) && itemstack1.getCount() < itemstack1.getMaxStackSize()) {
+            if (itemstack1.isEmpty() || (ItemStack.isSameItemSameTags(itemstack1, itemstack) && itemstack1.getCount() < itemstack1.getMaxStackSize())) {
                 return true;
             }
         }
diff --git a/internal/v1_20_R3/src/main/java/com/lishid/openinv/internal/v1_20_R3/SpecialPlayerInventory.java b/internal/v1_20_R3/src/main/java/com/lishid/openinv/internal/v1_20_R3/SpecialPlayerInventory.java
index 5eac3b1b..e4c278b2 100644
--- a/internal/v1_20_R3/src/main/java/com/lishid/openinv/internal/v1_20_R3/SpecialPlayerInventory.java
+++ b/internal/v1_20_R3/src/main/java/com/lishid/openinv/internal/v1_20_R3/SpecialPlayerInventory.java
@@ -66,7 +66,7 @@ public class SpecialPlayerInventory extends Inventory implements ISpecialPlayerI
     private List<NonNullList<ItemStack>> compartments;
 
     public SpecialPlayerInventory(@NotNull org.bukkit.entity.Player bukkitPlayer, @NotNull Boolean online) {
-        super(PlayerDataManager.getHandle(bukkitPlayer));
+        super(PlayerManager.getHandle(bukkitPlayer));
         this.inventory = new CraftInventory(this);
         this.playerOnline = online;
         this.player = super.player;
@@ -84,7 +84,7 @@ public void setPlayerOnline(@NotNull org.bukkit.entity.Player player) {
         }
 
         Player offlinePlayer = this.player;
-        Player onlinePlayer = PlayerDataManager.getHandle(player);
+        Player onlinePlayer = PlayerManager.getHandle(player);
         onlinePlayer.getInventory().transaction.addAll(this.transaction);
 
         // Set owner to new player.
diff --git a/internal/v1_20_R4/pom.xml b/internal/v1_20_R4/pom.xml
index 666318e0..5e8673a7 100644
--- a/internal/v1_20_R4/pom.xml
+++ b/internal/v1_20_R4/pom.xml
@@ -30,8 +30,8 @@
   <name>OpenInvAdapter1_20_R4</name>
 
   <properties>
-    <maven.compiler.source>21</maven.compiler.source>
-    <maven.compiler.target>21</maven.compiler.target>
+    <maven.compiler.system>21</maven.compiler.system>
+    <maven.compiler.release>21</maven.compiler.release>
     <spigot.version>1.20.6-R0.1-SNAPSHOT</spigot.version>
   </properties>
 
@@ -51,10 +51,9 @@
     <dependency>
       <artifactId>openinvapi</artifactId>
       <groupId>com.lishid</groupId>
-      <scope>provided</scope>
     </dependency>
     <dependency>
-      <artifactId>openinvplugincore</artifactId>
+      <artifactId>openinvcommon</artifactId>
       <groupId>com.lishid</groupId>
     </dependency>
     <dependency>
@@ -65,9 +64,6 @@
 
   <build>
     <plugins>
-      <plugin>
-        <artifactId>maven-shade-plugin</artifactId>
-      </plugin>
       <plugin>
         <artifactId>maven-compiler-plugin</artifactId>
       </plugin>
diff --git a/internal/v1_20_R4/src/main/java/com/lishid/openinv/internal/v1_20_R4/AnySilentContainer.java b/internal/v1_20_R4/src/main/java/com/lishid/openinv/internal/v1_20_R4/AnySilentContainer.java
index 7731837d..f04de59b 100644
--- a/internal/v1_20_R4/src/main/java/com/lishid/openinv/internal/v1_20_R4/AnySilentContainer.java
+++ b/internal/v1_20_R4/src/main/java/com/lishid/openinv/internal/v1_20_R4/AnySilentContainer.java
@@ -16,9 +16,9 @@
 
 package com.lishid.openinv.internal.v1_20_R4;
 
-import com.lishid.openinv.OpenInv;
 import com.lishid.openinv.internal.IAnySilentContainer;
 import com.lishid.openinv.util.ReflectionHelper;
+import com.lishid.openinv.util.lang.LanguageManager;
 import net.minecraft.core.BlockPos;
 import net.minecraft.network.chat.Component;
 import net.minecraft.server.level.ServerPlayer;
@@ -50,15 +50,18 @@
 
 public class AnySilentContainer implements IAnySilentContainer {
 
+    private final @NotNull Logger logger;
+    private final @NotNull LanguageManager lang;
     private @Nullable Field serverPlayerGameModeGameType;
 
-    public AnySilentContainer() {
+    public AnySilentContainer(@NotNull Logger logger, @NotNull LanguageManager lang) {
+        this.logger = logger;
+        this.lang = lang;
         try {
             try {
                 this.serverPlayerGameModeGameType = ServerPlayerGameMode.class.getDeclaredField("b");
                 this.serverPlayerGameModeGameType.setAccessible(true);
             } catch (NoSuchFieldException e) {
-                Logger logger = OpenInv.getPlugin(OpenInv.class).getLogger();
                 logger.warning("ServerPlayerGameMode#gameModeForPlayer's obfuscated name has changed!");
                 logger.warning("Please report this at https://github.com/Jikoo/OpenInv/issues");
                 logger.warning("Attempting to fall through using reflection. Please verify that SilentContainer does not fail.");
@@ -66,7 +69,6 @@ public AnySilentContainer() {
                 this.serverPlayerGameModeGameType = ReflectionHelper.grabFieldByType(ServerPlayerGameMode.class, GameType.class);
             }
         } catch (SecurityException e) {
-            Logger logger = OpenInv.getPlugin(OpenInv.class).getLogger();
             logger.warning("Unable to directly write player game mode! SilentContainer will fail.");
             logger.log(java.util.logging.Level.WARNING, "Error obtaining GameType field", e);
         }
@@ -85,7 +87,7 @@ public boolean activateContainer(
             return true;
         }
 
-        ServerPlayer player = PlayerDataManager.getHandle(bukkitPlayer);
+        ServerPlayer player = PlayerManager.getHandle(bukkitPlayer);
 
         final net.minecraft.world.level.Level level = player.level();
         final BlockPos blockPos = new BlockPos(bukkitBlock.getX(), bukkitBlock.getY(), bukkitBlock.getZ());
@@ -100,10 +102,10 @@ public boolean activateContainer(
             PlayerEnderChestContainer enderChest = player.getEnderChestInventory();
             enderChest.setActiveChest(enderChestTile);
             player.openMenu(new SimpleMenuProvider((containerCounter, playerInventory, ignored) -> {
-                MenuType<?> containers = PlayerDataManager.getContainers(enderChest.getContainerSize());
+                MenuType<?> containers = PlayerManager.getContainers(enderChest.getContainerSize());
                 int rows = enderChest.getContainerSize() / 9;
                 return new ChestMenu(containers, containerCounter, playerInventory, enderChest, rows);
-            }, Component.translatable(("container.enderchest"))));
+            }, Component.translatable("container.enderchest")));
             bukkitPlayer.incrementStatistic(Statistic.ENDERCHEST_OPENED);
             return true;
         }
@@ -121,7 +123,7 @@ public boolean activateContainer(
             menuProvider = chestBlock.getMenuProvider(blockState, level, blockPos, true);
 
             if (menuProvider == null) {
-                OpenInv.getPlugin(OpenInv.class).sendSystemMessage(bukkitPlayer, "messages.error.lootNotGenerated");
+                lang.sendSystemMessage(bukkitPlayer, "messages.error.lootNotGenerated");
                 return false;
             }
 
@@ -153,7 +155,7 @@ public boolean activateContainer(
 
         if (blockEntity instanceof RandomizableContainerBlockEntity lootable) {
             if (lootable.lootTable != null) {
-                OpenInv.getPlugin(OpenInv.class).sendSystemMessage(bukkitPlayer, "messages.error.lootNotGenerated");
+                lang.sendSystemMessage(bukkitPlayer, "messages.error.lootNotGenerated");
                 return false;
             }
         }
@@ -171,7 +173,7 @@ public void deactivateContainer(@NotNull final Player bukkitPlayer) {
             return;
         }
 
-        ServerPlayer player = PlayerDataManager.getHandle(bukkitPlayer);
+        ServerPlayer player = PlayerManager.getHandle(bukkitPlayer);
 
         // Force game mode change without informing plugins or players.
         // Regular game mode set calls GameModeChangeEvent and is cancellable.
@@ -199,7 +201,6 @@ private void forceGameType(final ServerPlayer player, final GameType gameMode) {
             this.serverPlayerGameModeGameType.setAccessible(true);
             this.serverPlayerGameModeGameType.set(player.gameMode, gameMode);
         } catch (IllegalArgumentException | IllegalAccessException e) {
-            Logger logger = OpenInv.getPlugin(OpenInv.class).getLogger();
             logger.log(java.util.logging.Level.WARNING, "Error bypassing GameModeChangeEvent", e);
         }
     }
diff --git a/internal/v1_20_R4/src/main/java/com/lishid/openinv/internal/v1_20_R4/InternalAccessor.java b/internal/v1_20_R4/src/main/java/com/lishid/openinv/internal/v1_20_R4/InternalAccessor.java
new file mode 100644
index 00000000..ff599644
--- /dev/null
+++ b/internal/v1_20_R4/src/main/java/com/lishid/openinv/internal/v1_20_R4/InternalAccessor.java
@@ -0,0 +1,64 @@
+package com.lishid.openinv.internal.v1_20_R4;
+
+import com.lishid.openinv.internal.Accessor;
+import com.lishid.openinv.internal.IAnySilentContainer;
+import com.lishid.openinv.internal.ISpecialEnderChest;
+import com.lishid.openinv.internal.ISpecialInventory;
+import com.lishid.openinv.internal.ISpecialPlayerInventory;
+import com.lishid.openinv.util.lang.LanguageManager;
+import net.minecraft.world.Container;
+import org.bukkit.configuration.ConfigurationSection;
+import org.bukkit.craftbukkit.v1_20_R4.inventory.CraftInventory;
+import org.bukkit.entity.Player;
+import org.bukkit.inventory.Inventory;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.logging.Logger;
+
+public class InternalAccessor implements Accessor {
+
+  private final @NotNull PlayerManager manager;
+  private final @NotNull AnySilentContainer anySilentContainer;
+
+  public InternalAccessor(@NotNull Logger logger, @NotNull LanguageManager lang) {
+    manager = new PlayerManager(logger, lang);
+    anySilentContainer = new AnySilentContainer(logger, lang);
+  }
+
+  @Override
+  public @NotNull PlayerManager getPlayerManager() {
+    return manager;
+  }
+
+  @Override
+  public @NotNull IAnySilentContainer getAnySilentContainer() {
+    return anySilentContainer;
+  }
+
+  @Override
+  public @NotNull ISpecialPlayerInventory createPlayerInventory(@NotNull Player player) {
+    return new SpecialPlayerInventory(player, player.isOnline());
+  }
+
+  @Override
+  public @NotNull ISpecialEnderChest createEnderChest(@NotNull Player player) {
+    return new SpecialEnderChest(player, player.isOnline());
+  }
+
+  @Override
+  public <T extends ISpecialInventory> @Nullable T get(@NotNull Inventory bukkitInventory, @NotNull Class<T> clazz) {
+    if (!(bukkitInventory instanceof CraftInventory craftInventory)) {
+      return null;
+    }
+    Container container = craftInventory.getInventory();
+    if (clazz.isInstance(container)) {
+      return clazz.cast(container);
+    }
+    return null;
+  }
+
+  @Override
+  public void reload(@NotNull ConfigurationSection config) {}
+
+}
diff --git a/internal/v1_20_R4/src/main/java/com/lishid/openinv/internal/v1_20_R4/OpenPlayer.java b/internal/v1_20_R4/src/main/java/com/lishid/openinv/internal/v1_20_R4/OpenPlayer.java
index be7fbb47..9223fa19 100644
--- a/internal/v1_20_R4/src/main/java/com/lishid/openinv/internal/v1_20_R4/OpenPlayer.java
+++ b/internal/v1_20_R4/src/main/java/com/lishid/openinv/internal/v1_20_R4/OpenPlayer.java
@@ -16,6 +16,7 @@
 
 package com.lishid.openinv.internal.v1_20_R4;
 
+import com.lishid.openinv.event.OpenEvents;
 import com.mojang.logging.LogUtils;
 import net.minecraft.Util;
 import net.minecraft.nbt.CompoundTag;
@@ -80,17 +81,24 @@ public class OpenPlayer extends CraftPlayer {
         "Brain"
     );
 
-    public OpenPlayer(CraftServer server, ServerPlayer entity) {
+    private final PlayerManager manager;
+
+    OpenPlayer(CraftServer server, ServerPlayer entity, PlayerManager manager) {
         super(server, entity);
+        this.manager = manager;
     }
 
     @Override
     public void loadData() {
-        PlayerDataManager.loadData(getHandle());
+        manager.loadData(getHandle());
     }
 
     @Override
     public void saveData() {
+        if (OpenEvents.saveCancelled(this)) {
+            return;
+        }
+
         ServerPlayer player = this.getHandle();
         // See net.minecraft.world.level.storage.PlayerDataStorage#save(EntityHuman)
         try {
diff --git a/internal/v1_20_R4/src/main/java/com/lishid/openinv/internal/v1_20_R4/PlayerDataManager.java b/internal/v1_20_R4/src/main/java/com/lishid/openinv/internal/v1_20_R4/PlayerManager.java
similarity index 93%
rename from internal/v1_20_R4/src/main/java/com/lishid/openinv/internal/v1_20_R4/PlayerDataManager.java
rename to internal/v1_20_R4/src/main/java/com/lishid/openinv/internal/v1_20_R4/PlayerManager.java
index 430fa975..2acab9a3 100644
--- a/internal/v1_20_R4/src/main/java/com/lishid/openinv/internal/v1_20_R4/PlayerDataManager.java
+++ b/internal/v1_20_R4/src/main/java/com/lishid/openinv/internal/v1_20_R4/PlayerManager.java
@@ -16,11 +16,10 @@
 
 package com.lishid.openinv.internal.v1_20_R4;
 
-import com.lishid.openinv.OpenInv;
-import com.lishid.openinv.internal.IPlayerDataManager;
 import com.lishid.openinv.internal.ISpecialInventory;
 import com.lishid.openinv.internal.InventoryViewTitle;
 import com.lishid.openinv.internal.OpenInventoryView;
+import com.lishid.openinv.util.lang.LanguageManager;
 import com.mojang.authlib.GameProfile;
 import com.mojang.serialization.Dynamic;
 import net.minecraft.nbt.CompoundTag;
@@ -48,7 +47,6 @@
 import org.bukkit.craftbukkit.v1_20_R4.inventory.CraftContainer;
 import org.bukkit.entity.Player;
 import org.bukkit.inventory.InventoryView;
-import org.bukkit.plugin.java.JavaPlugin;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
@@ -56,7 +54,7 @@
 import java.util.UUID;
 import java.util.logging.Logger;
 
-public class PlayerDataManager implements IPlayerDataManager {
+public class PlayerManager implements com.lishid.openinv.internal.PlayerManager {
 
     private static boolean paper;
 
@@ -69,13 +67,16 @@ public class PlayerDataManager implements IPlayerDataManager {
         }
     }
 
+    private final @NotNull Logger logger;
+    private final @NotNull LanguageManager lang;
     private @Nullable Field bukkitEntity;
 
-    public PlayerDataManager() {
+    public PlayerManager(@NotNull Logger logger, @NotNull LanguageManager lang) {
+        this.logger = logger;
+        this.lang = lang;
         try {
             bukkitEntity = Entity.class.getDeclaredField("bukkitEntity");
         } catch (NoSuchFieldException e) {
-            Logger logger = JavaPlugin.getPlugin(OpenInv.class).getLogger();
             logger.warning("Unable to obtain field to inject custom save process - certain player data may be lost when saving!");
             logger.log(java.util.logging.Level.WARNING, e.getMessage(), e);
             bukkitEntity = null;
@@ -156,7 +157,7 @@ public PlayerDataManager() {
         try {
             injectPlayer(entity);
         } catch (IllegalAccessException e) {
-            JavaPlugin.getPlugin(OpenInv.class).getLogger().log(
+            logger.log(
                 java.util.logging.Level.WARNING,
                 e,
                 () -> "Unable to inject ServerPlayer, certain player data may be lost when saving!");
@@ -165,7 +166,7 @@ public PlayerDataManager() {
         return entity;
     }
 
-    static boolean loadData(@NotNull ServerPlayer player) {
+    boolean loadData(@NotNull ServerPlayer player) {
         // See CraftPlayer#loadData
         CompoundTag loadedData = player.server.getPlayerList().playerIo.load(player).orElse(null);
 
@@ -189,7 +190,7 @@ static boolean loadData(@NotNull ServerPlayer player) {
         return true;
     }
 
-    private static void parseWorld(@NotNull ServerPlayer player, @NotNull CompoundTag loadedData) {
+    private void parseWorld(@NotNull ServerPlayer player, @NotNull CompoundTag loadedData) {
         // See PlayerList#placeNewPlayer
         World bukkitWorld;
         if (loadedData.contains("WorldUUIDMost") && loadedData.contains("WorldUUIDLeast")) {
@@ -201,7 +202,7 @@ private static void parseWorld(@NotNull ServerPlayer player, @NotNull CompoundTa
         } else {
             // Vanilla player data.
             DimensionType.parseLegacy(new Dynamic<>(NbtOps.INSTANCE, loadedData.get("Dimension")))
-                .resultOrPartial(JavaPlugin.getPlugin(OpenInv.class).getLogger()::warning)
+                .resultOrPartial(logger::warning)
                 .map(player.server::getLevel)
                 // If ServerLevel exists, set, otherwise move to spawn.
                 .ifPresentOrElse(player::setServerLevel, () -> player.spawnIn(null));
@@ -221,7 +222,7 @@ private void injectPlayer(ServerPlayer player) throws IllegalAccessException {
 
         bukkitEntity.setAccessible(true);
 
-        bukkitEntity.set(player, new OpenPlayer(player.server.server, player));
+        bukkitEntity.set(player, new OpenPlayer(player.server.server, player, this));
     }
 
     @Override
@@ -234,7 +235,7 @@ private void injectPlayer(ServerPlayer player) throws IllegalAccessException {
             injectPlayer(nmsPlayer);
             return nmsPlayer.getBukkitEntity();
         } catch (IllegalAccessException e) {
-            JavaPlugin.getPlugin(OpenInv.class).getLogger().log(
+            logger.log(
                 java.util.logging.Level.WARNING,
                 e,
                 () -> "Unable to inject ServerPlayer, certain player data may be lost when saving!");
@@ -257,7 +258,7 @@ private void injectPlayer(ServerPlayer player) throws IllegalAccessException {
             return player.openInventory(inventory.getBukkitInventory());
         }
 
-        InventoryView view = new OpenInventoryView(player, inventory, title.getTitle(player, inventory));
+        InventoryView view = new OpenInventoryView(player, inventory, title.getTitle(lang, player, inventory));
         AbstractContainerMenu container = new CraftContainer(view, nmsPlayer, nmsPlayer.nextContainerCounter()) {
             @Override
             public MenuType<?> getType() {
diff --git a/internal/v1_20_R4/src/main/java/com/lishid/openinv/internal/v1_20_R4/SpecialEnderChest.java b/internal/v1_20_R4/src/main/java/com/lishid/openinv/internal/v1_20_R4/SpecialEnderChest.java
index 712a68af..d38ac428 100644
--- a/internal/v1_20_R4/src/main/java/com/lishid/openinv/internal/v1_20_R4/SpecialEnderChest.java
+++ b/internal/v1_20_R4/src/main/java/com/lishid/openinv/internal/v1_20_R4/SpecialEnderChest.java
@@ -50,9 +50,9 @@ public class SpecialEnderChest extends PlayerEnderChestContainer implements ISpe
     private boolean playerOnline;
 
     public SpecialEnderChest(final org.bukkit.entity.Player player, final Boolean online) {
-        super(PlayerDataManager.getHandle(player));
+        super(PlayerManager.getHandle(player));
         this.inventory = new CraftInventory(this);
-        this.owner = PlayerDataManager.getHandle(player);
+        this.owner = PlayerManager.getHandle(player);
         this.playerOnline = online;
         this.items = this.owner.getEnderChestInventory().items;
     }
@@ -74,7 +74,7 @@ public void setPlayerOnline(@NotNull final org.bukkit.entity.Player player) {
         }
 
         ServerPlayer offlinePlayer = this.owner;
-        ServerPlayer onlinePlayer = PlayerDataManager.getHandle(player);
+        ServerPlayer onlinePlayer = PlayerManager.getHandle(player);
 
         // Set owner to new player.
         this.owner = onlinePlayer;
@@ -199,7 +199,7 @@ public ItemStack addItem(ItemStack itemstack) {
     @Override
     public boolean canAddItem(ItemStack itemstack) {
         for (ItemStack itemstack1 : this.items) {
-            if (itemstack1.isEmpty() || ItemStack.isSameItemSameComponents(itemstack1, itemstack) && itemstack1.getCount() < itemstack1.getMaxStackSize()) {
+            if (itemstack1.isEmpty() || (ItemStack.isSameItemSameComponents(itemstack1, itemstack) && itemstack1.getCount() < itemstack1.getMaxStackSize())) {
                 return true;
             }
         }
diff --git a/internal/v1_20_R4/src/main/java/com/lishid/openinv/internal/v1_20_R4/SpecialPlayerInventory.java b/internal/v1_20_R4/src/main/java/com/lishid/openinv/internal/v1_20_R4/SpecialPlayerInventory.java
index a447f63d..155f4224 100644
--- a/internal/v1_20_R4/src/main/java/com/lishid/openinv/internal/v1_20_R4/SpecialPlayerInventory.java
+++ b/internal/v1_20_R4/src/main/java/com/lishid/openinv/internal/v1_20_R4/SpecialPlayerInventory.java
@@ -63,7 +63,7 @@ public class SpecialPlayerInventory extends Inventory implements ISpecialPlayerI
     private List<NonNullList<ItemStack>> compartments;
 
     public SpecialPlayerInventory(@NotNull org.bukkit.entity.Player bukkitPlayer, @NotNull Boolean online) {
-        super(PlayerDataManager.getHandle(bukkitPlayer));
+        super(PlayerManager.getHandle(bukkitPlayer));
         this.inventory = new CraftInventory(this);
         this.playerOnline = online;
         this.player = super.player;
@@ -81,7 +81,7 @@ public void setPlayerOnline(@NotNull org.bukkit.entity.Player player) {
         }
 
         Player offlinePlayer = this.player;
-        Player onlinePlayer = PlayerDataManager.getHandle(player);
+        Player onlinePlayer = PlayerManager.getHandle(player);
         onlinePlayer.getInventory().transaction.addAll(this.transaction);
 
         // Set owner to new player.
diff --git a/internal/v1_21_R1/pom.xml b/internal/v1_21_R1/pom.xml
index 2d2b6b3e..b3aa9c15 100644
--- a/internal/v1_21_R1/pom.xml
+++ b/internal/v1_21_R1/pom.xml
@@ -30,8 +30,8 @@
   <name>OpenInvAdapter1_21_R1</name>
 
   <properties>
-    <maven.compiler.source>21</maven.compiler.source>
-    <maven.compiler.target>21</maven.compiler.target>
+    <maven.compiler.system>21</maven.compiler.system>
+    <maven.compiler.release>21</maven.compiler.release>
     <spigot.version>1.21-R0.1-SNAPSHOT</spigot.version>
   </properties>
 
@@ -51,10 +51,9 @@
     <dependency>
       <artifactId>openinvapi</artifactId>
       <groupId>com.lishid</groupId>
-      <scope>provided</scope>
     </dependency>
     <dependency>
-      <artifactId>openinvplugincore</artifactId>
+      <artifactId>openinvcommon</artifactId>
       <groupId>com.lishid</groupId>
     </dependency>
     <dependency>
@@ -65,9 +64,6 @@
 
   <build>
     <plugins>
-      <plugin>
-        <artifactId>maven-shade-plugin</artifactId>
-      </plugin>
       <plugin>
         <artifactId>maven-compiler-plugin</artifactId>
       </plugin>
diff --git a/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/AnySilentContainer.java b/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/AnySilentContainer.java
index d03f25aa..15faeff8 100644
--- a/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/AnySilentContainer.java
+++ b/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/AnySilentContainer.java
@@ -16,9 +16,9 @@
 
 package com.lishid.openinv.internal.v1_21_R1;
 
-import com.lishid.openinv.OpenInv;
 import com.lishid.openinv.internal.IAnySilentContainer;
 import com.lishid.openinv.util.ReflectionHelper;
+import com.lishid.openinv.util.lang.LanguageManager;
 import net.minecraft.core.BlockPos;
 import net.minecraft.network.chat.Component;
 import net.minecraft.server.level.ServerPlayer;
@@ -50,15 +50,18 @@
 
 public class AnySilentContainer implements IAnySilentContainer {
 
+    private final @NotNull Logger logger;
+    private final @NotNull LanguageManager lang;
     private @Nullable Field serverPlayerGameModeGameType;
 
-    public AnySilentContainer() {
+    public AnySilentContainer(@NotNull Logger logger, @NotNull LanguageManager lang) {
+        this.logger = logger;
+        this.lang = lang;
         try {
             try {
                 this.serverPlayerGameModeGameType = ServerPlayerGameMode.class.getDeclaredField("b");
                 this.serverPlayerGameModeGameType.setAccessible(true);
             } catch (NoSuchFieldException e) {
-                Logger logger = OpenInv.getPlugin(OpenInv.class).getLogger();
                 logger.warning("ServerPlayerGameMode#gameModeForPlayer's obfuscated name has changed!");
                 logger.warning("Please report this at https://github.com/Jikoo/OpenInv/issues");
                 logger.warning("Attempting to fall through using reflection. Please verify that SilentContainer does not fail.");
@@ -66,7 +69,6 @@ public AnySilentContainer() {
                 this.serverPlayerGameModeGameType = ReflectionHelper.grabFieldByType(ServerPlayerGameMode.class, GameType.class);
             }
         } catch (SecurityException e) {
-            Logger logger = OpenInv.getPlugin(OpenInv.class).getLogger();
             logger.warning("Unable to directly write player game mode! SilentContainer will fail.");
             logger.log(java.util.logging.Level.WARNING, "Error obtaining GameType field", e);
         }
@@ -85,7 +87,7 @@ public boolean activateContainer(
             return true;
         }
 
-        ServerPlayer player = PlayerDataManager.getHandle(bukkitPlayer);
+        ServerPlayer player = PlayerManager.getHandle(bukkitPlayer);
 
         final net.minecraft.world.level.Level level = player.level();
         final BlockPos blockPos = new BlockPos(bukkitBlock.getX(), bukkitBlock.getY(), bukkitBlock.getZ());
@@ -100,10 +102,10 @@ public boolean activateContainer(
             PlayerEnderChestContainer enderChest = player.getEnderChestInventory();
             enderChest.setActiveChest(enderChestTile);
             player.openMenu(new SimpleMenuProvider((containerCounter, playerInventory, ignored) -> {
-                MenuType<?> containers = PlayerDataManager.getContainers(enderChest.getContainerSize());
+                MenuType<?> containers = PlayerManager.getContainers(enderChest.getContainerSize());
                 int rows = enderChest.getContainerSize() / 9;
                 return new ChestMenu(containers, containerCounter, playerInventory, enderChest, rows);
-            }, Component.translatable(("container.enderchest"))));
+            }, Component.translatable("container.enderchest")));
             bukkitPlayer.incrementStatistic(Statistic.ENDERCHEST_OPENED);
             return true;
         }
@@ -121,7 +123,7 @@ public boolean activateContainer(
             menuProvider = chestBlock.getMenuProvider(blockState, level, blockPos, true);
 
             if (menuProvider == null) {
-                OpenInv.getPlugin(OpenInv.class).sendSystemMessage(bukkitPlayer, "messages.error.lootNotGenerated");
+                lang.sendSystemMessage(bukkitPlayer, "messages.error.lootNotGenerated");
                 return false;
             }
 
@@ -153,7 +155,7 @@ public boolean activateContainer(
 
         if (blockEntity instanceof RandomizableContainerBlockEntity lootable) {
             if (lootable.lootTable != null) {
-                OpenInv.getPlugin(OpenInv.class).sendSystemMessage(bukkitPlayer, "messages.error.lootNotGenerated");
+                lang.sendSystemMessage(bukkitPlayer, "messages.error.lootNotGenerated");
                 return false;
             }
         }
@@ -171,7 +173,7 @@ public void deactivateContainer(@NotNull final Player bukkitPlayer) {
             return;
         }
 
-        ServerPlayer player = PlayerDataManager.getHandle(bukkitPlayer);
+        ServerPlayer player = PlayerManager.getHandle(bukkitPlayer);
 
         // Force game mode change without informing plugins or players.
         // Regular game mode set calls GameModeChangeEvent and is cancellable.
@@ -199,7 +201,6 @@ private void forceGameType(final ServerPlayer player, final GameType gameMode) {
             this.serverPlayerGameModeGameType.setAccessible(true);
             this.serverPlayerGameModeGameType.set(player.gameMode, gameMode);
         } catch (IllegalArgumentException | IllegalAccessException e) {
-            Logger logger = OpenInv.getPlugin(OpenInv.class).getLogger();
             logger.log(java.util.logging.Level.WARNING, "Error bypassing GameModeChangeEvent", e);
         }
     }
diff --git a/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/InternalAccessor.java b/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/InternalAccessor.java
new file mode 100644
index 00000000..59f3481a
--- /dev/null
+++ b/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/InternalAccessor.java
@@ -0,0 +1,78 @@
+package com.lishid.openinv.internal.v1_21_R1;
+
+import com.lishid.openinv.internal.Accessor;
+import com.lishid.openinv.internal.IAnySilentContainer;
+import com.lishid.openinv.internal.ISpecialEnderChest;
+import com.lishid.openinv.internal.ISpecialInventory;
+import com.lishid.openinv.internal.ISpecialPlayerInventory;
+import com.lishid.openinv.internal.v1_21_R1.inventory.OpenInventory;
+import com.lishid.openinv.internal.v1_21_R1.inventory.Placeholders;
+import com.lishid.openinv.util.lang.LanguageManager;
+import net.minecraft.world.Container;
+import org.bukkit.configuration.ConfigurationSection;
+import org.bukkit.craftbukkit.v1_21_R1.inventory.CraftInventory;
+import org.bukkit.entity.Player;
+import org.bukkit.inventory.Inventory;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+public class InternalAccessor implements Accessor {
+
+  private final @NotNull Logger logger;
+  private final @NotNull PlayerManager manager;
+  private final @NotNull AnySilentContainer anySilentContainer;
+
+  public InternalAccessor(@NotNull Logger logger, @NotNull LanguageManager lang) {
+    this.logger = logger;
+    manager = new PlayerManager(logger, lang);
+    anySilentContainer = new AnySilentContainer(logger, lang);
+  }
+
+  @Override
+  public @NotNull PlayerManager getPlayerManager() {
+    return manager;
+  }
+
+  @Override
+  public @NotNull IAnySilentContainer getAnySilentContainer() {
+    return anySilentContainer;
+  }
+
+  @Override
+  public @NotNull ISpecialPlayerInventory createPlayerInventory(@NotNull Player player) {
+    return new OpenInventory(player);
+  }
+
+  @Override
+  public @NotNull ISpecialEnderChest createEnderChest(@NotNull Player player) {
+    return new SpecialEnderChest(player, player.isOnline());
+  }
+
+  @Override
+  public <T extends ISpecialInventory> @Nullable T get(@NotNull Inventory bukkitInventory, @NotNull Class<T> clazz) {
+    if (!(bukkitInventory instanceof CraftInventory craftInventory)) {
+      return null;
+    }
+    Container container = craftInventory.getInventory();
+    if (clazz.isInstance(container)) {
+      return clazz.cast(container);
+    }
+    return null;
+  }
+
+  @Override
+  public void reload(@NotNull ConfigurationSection config) {
+    ConfigurationSection placeholders = config.getConfigurationSection("placeholders");
+    if (placeholders != null) {
+      try {
+        Placeholders.load(placeholders);
+      } catch (Exception e) {
+        logger.log(Level.WARNING, "Caught exception loading placeholder overrides!", e);
+      }
+    }
+  }
+
+}
diff --git a/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/OpenPlayer.java b/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/OpenPlayer.java
index 6a10ada3..ac07285d 100644
--- a/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/OpenPlayer.java
+++ b/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/OpenPlayer.java
@@ -16,6 +16,7 @@
 
 package com.lishid.openinv.internal.v1_21_R1;
 
+import com.lishid.openinv.event.OpenEvents;
 import com.mojang.logging.LogUtils;
 import net.minecraft.Util;
 import net.minecraft.nbt.CompoundTag;
@@ -79,17 +80,24 @@ public class OpenPlayer extends CraftPlayer {
         "Brain"
     );
 
-    public OpenPlayer(CraftServer server, ServerPlayer entity) {
+    private final PlayerManager manager;
+
+    OpenPlayer(CraftServer server, ServerPlayer entity, PlayerManager manager) {
         super(server, entity);
+        this.manager = manager;
     }
 
     @Override
     public void loadData() {
-        PlayerDataManager.loadData(getHandle());
+        manager.loadData(getHandle());
     }
 
     @Override
     public void saveData() {
+        if (OpenEvents.saveCancelled(this)) {
+            return;
+        }
+
         ServerPlayer player = this.getHandle();
         // See net.minecraft.world.level.storage.PlayerDataStorage#save(EntityHuman)
         try {
diff --git a/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/PlayerDataManager.java b/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/PlayerManager.java
similarity index 93%
rename from internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/PlayerDataManager.java
rename to internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/PlayerManager.java
index 4660d80a..2c81a192 100644
--- a/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/PlayerDataManager.java
+++ b/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/PlayerManager.java
@@ -16,13 +16,11 @@
 
 package com.lishid.openinv.internal.v1_21_R1;
 
-import com.github.jikoo.planarwrappers.function.TriFunction;
-import com.lishid.openinv.OpenInv;
-import com.lishid.openinv.internal.IPlayerDataManager;
 import com.lishid.openinv.internal.ISpecialInventory;
 import com.lishid.openinv.internal.InventoryViewTitle;
 import com.lishid.openinv.internal.OpenInventoryView;
 import com.lishid.openinv.internal.v1_21_R1.inventory.OpenInventory;
+import com.lishid.openinv.util.lang.LanguageManager;
 import com.mojang.authlib.GameProfile;
 import com.mojang.serialization.Dynamic;
 import net.minecraft.nbt.CompoundTag;
@@ -39,6 +37,7 @@
 import net.minecraft.world.inventory.MenuType;
 import net.minecraft.world.level.Level;
 import net.minecraft.world.level.dimension.DimensionType;
+import org.apache.commons.lang3.function.TriFunction;
 import org.bukkit.Bukkit;
 import org.bukkit.OfflinePlayer;
 import org.bukkit.Server;
@@ -50,7 +49,6 @@
 import org.bukkit.craftbukkit.v1_21_R1.inventory.CraftContainer;
 import org.bukkit.entity.Player;
 import org.bukkit.inventory.InventoryView;
-import org.bukkit.plugin.java.JavaPlugin;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
@@ -58,7 +56,7 @@
 import java.util.UUID;
 import java.util.logging.Logger;
 
-public class PlayerDataManager implements IPlayerDataManager {
+public class PlayerManager implements com.lishid.openinv.internal.PlayerManager {
 
     private static boolean paper;
     private static TriFunction<Player, ISpecialInventory, String, InventoryView> viewProvider;
@@ -78,13 +76,16 @@ public class PlayerDataManager implements IPlayerDataManager {
         }
     }
 
+    private final @NotNull Logger logger;
+    private final @NotNull LanguageManager lang;
     private @Nullable Field bukkitEntity;
 
-    public PlayerDataManager() {
+    public PlayerManager(@NotNull Logger logger, @NotNull LanguageManager lang) {
+        this.logger = logger;
+        this.lang = lang;
         try {
             bukkitEntity = Entity.class.getDeclaredField("bukkitEntity");
         } catch (NoSuchFieldException e) {
-            Logger logger = JavaPlugin.getPlugin(OpenInv.class).getLogger();
             logger.warning("Unable to obtain field to inject custom save process - certain player data may be lost when saving!");
             logger.log(java.util.logging.Level.WARNING, e.getMessage(), e);
             bukkitEntity = null;
@@ -165,7 +166,7 @@ public PlayerDataManager() {
         try {
             injectPlayer(entity);
         } catch (IllegalAccessException e) {
-            JavaPlugin.getPlugin(OpenInv.class).getLogger().log(
+            logger.log(
                 java.util.logging.Level.WARNING,
                 e,
                 () -> "Unable to inject ServerPlayer, certain player data may be lost when saving!");
@@ -174,7 +175,7 @@ public PlayerDataManager() {
         return entity;
     }
 
-    static boolean loadData(@NotNull ServerPlayer player) {
+    boolean loadData(@NotNull ServerPlayer player) {
         // See CraftPlayer#loadData
         CompoundTag loadedData = player.server.getPlayerList().playerIo.load(player).orElse(null);
 
@@ -198,7 +199,7 @@ static boolean loadData(@NotNull ServerPlayer player) {
         return true;
     }
 
-    private static void parseWorld(@NotNull ServerPlayer player, @NotNull CompoundTag loadedData) {
+    private void parseWorld(@NotNull ServerPlayer player, @NotNull CompoundTag loadedData) {
         // See PlayerList#placeNewPlayer
         World bukkitWorld;
         if (loadedData.contains("WorldUUIDMost") && loadedData.contains("WorldUUIDLeast")) {
@@ -210,7 +211,7 @@ private static void parseWorld(@NotNull ServerPlayer player, @NotNull CompoundTa
         } else {
             // Vanilla player data.
             DimensionType.parseLegacy(new Dynamic<>(NbtOps.INSTANCE, loadedData.get("Dimension")))
-                .resultOrPartial(JavaPlugin.getPlugin(OpenInv.class).getLogger()::warning)
+                .resultOrPartial(logger::warning)
                 .map(player.server::getLevel)
                 // If ServerLevel exists, set, otherwise move to spawn.
                 .ifPresentOrElse(player::setServerLevel, () -> player.spawnIn(null));
@@ -230,7 +231,7 @@ private void injectPlayer(ServerPlayer player) throws IllegalAccessException {
 
         bukkitEntity.setAccessible(true);
 
-        bukkitEntity.set(player, new OpenPlayer(player.server.server, player));
+        bukkitEntity.set(player, new OpenPlayer(player.server.server, player, this));
     }
 
     @Override
@@ -243,7 +244,7 @@ private void injectPlayer(ServerPlayer player) throws IllegalAccessException {
             injectPlayer(nmsPlayer);
             return nmsPlayer.getBukkitEntity();
         } catch (IllegalAccessException e) {
-            JavaPlugin.getPlugin(OpenInv.class).getLogger().log(
+            logger.log(
                 java.util.logging.Level.WARNING,
                 e,
                 () -> "Unable to inject ServerPlayer, certain player data may be lost when saving!");
@@ -292,7 +293,7 @@ private void injectPlayer(ServerPlayer player) throws IllegalAccessException {
             return bukkitPlayer.openInventory(inventory.getBukkitInventory());
         }
 
-        String originalTitle = viewTitle.getTitle(bukkitPlayer, inventory);
+        String originalTitle = viewTitle.getTitle(lang, bukkitPlayer, inventory);
         InventoryView view = viewProvider.apply(bukkitPlayer, inventory, originalTitle);
         Component title = Component.literal(originalTitle);
         AbstractContainerMenu container = new CraftContainer(view, player, player.nextContainerCounter()) {
diff --git a/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/SpecialEnderChest.java b/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/SpecialEnderChest.java
index 512f2d95..a7d74c49 100644
--- a/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/SpecialEnderChest.java
+++ b/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/SpecialEnderChest.java
@@ -50,9 +50,9 @@ public class SpecialEnderChest extends PlayerEnderChestContainer implements ISpe
     private boolean playerOnline;
 
     public SpecialEnderChest(final org.bukkit.entity.Player player, final Boolean online) {
-        super(PlayerDataManager.getHandle(player));
+        super(PlayerManager.getHandle(player));
         this.inventory = new CraftInventory(this);
-        this.owner = PlayerDataManager.getHandle(player);
+        this.owner = PlayerManager.getHandle(player);
         this.playerOnline = online;
         this.items = this.owner.getEnderChestInventory().items;
     }
@@ -74,7 +74,7 @@ public void setPlayerOnline(@NotNull final org.bukkit.entity.Player player) {
         }
 
         ServerPlayer offlinePlayer = this.owner;
-        ServerPlayer onlinePlayer = PlayerDataManager.getHandle(player);
+        ServerPlayer onlinePlayer = PlayerManager.getHandle(player);
 
         // Set owner to new player.
         this.owner = onlinePlayer;
@@ -199,7 +199,7 @@ public ItemStack addItem(ItemStack itemstack) {
     @Override
     public boolean canAddItem(ItemStack itemstack) {
         for (ItemStack itemstack1 : this.items) {
-            if (itemstack1.isEmpty() || ItemStack.isSameItemSameComponents(itemstack1, itemstack) && itemstack1.getCount() < itemstack1.getMaxStackSize()) {
+            if (itemstack1.isEmpty() || (ItemStack.isSameItemSameComponents(itemstack1, itemstack) && itemstack1.getCount() < itemstack1.getMaxStackSize())) {
                 return true;
             }
         }
diff --git a/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/inventory/ContainerSlotCrafting.java b/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/inventory/ContainerSlotCrafting.java
index f3f241cf..a071e123 100644
--- a/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/inventory/ContainerSlotCrafting.java
+++ b/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/inventory/ContainerSlotCrafting.java
@@ -102,7 +102,7 @@ private SlotCrafting(Container container, int index, int x, int y) {
 
     @Override
     ItemStack getOrDefault() {
-      return isAvailable() ? items.get(ContainerSlotCrafting.this.index) : PlaceholderManager.survivalOnly(holder);
+      return isAvailable() ? items.get(ContainerSlotCrafting.this.index) : Placeholders.survivalOnly(holder);
     }
 
     @Override
diff --git a/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/inventory/ContainerSlotCraftingResult.java b/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/inventory/ContainerSlotCraftingResult.java
index 6b25d985..3bf9fb43 100644
--- a/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/inventory/ContainerSlotCraftingResult.java
+++ b/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/inventory/ContainerSlotCraftingResult.java
@@ -31,7 +31,7 @@ public Slot asMenuSlot(Container container, int index, int x, int y) {
       @Override
       ItemStack getOrDefault() {
         if (!ContainerSlotCrafting.isAvailable(holder)) {
-          return PlaceholderManager.survivalOnly(holder);
+          return Placeholders.survivalOnly(holder);
         }
         InventoryMenu inventoryMenu = holder.inventoryMenu;
         return inventoryMenu.getSlot(inventoryMenu.getResultSlotIndex()).getItem();
diff --git a/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/inventory/ContainerSlotCursor.java b/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/inventory/ContainerSlotCursor.java
index 65a9e33c..33b83df6 100644
--- a/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/inventory/ContainerSlotCursor.java
+++ b/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/inventory/ContainerSlotCursor.java
@@ -85,10 +85,10 @@ private SlotCursor(Container container, int index, int x, int y) {
     @Override
     ItemStack getOrDefault() {
       if (!isAvailable()) {
-        return PlaceholderManager.survivalOnly(holder);
+        return Placeholders.survivalOnly(holder);
       }
       ItemStack carried = holder.containerMenu.getCarried();
-      return carried.isEmpty() ? PlaceholderManager.cursor : carried;
+      return carried.isEmpty() ? Placeholders.cursor : carried;
     }
 
     @Override
diff --git a/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/inventory/ContainerSlotDrop.java b/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/inventory/ContainerSlotDrop.java
index 355ccd1f..e7fb80c5 100644
--- a/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/inventory/ContainerSlotDrop.java
+++ b/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/inventory/ContainerSlotDrop.java
@@ -63,8 +63,8 @@ private SlotDrop(Container container, int index, int x, int y) {
     @Override
     ItemStack getOrDefault() {
       return holder.connection != null && !holder.connection.isDisconnected()
-          ? PlaceholderManager.drop
-          : PlaceholderManager.blockedOffline;
+          ? Placeholders.drop
+          : Placeholders.blockedOffline;
     }
 
     @Override
diff --git a/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/inventory/ContainerSlotEquipment.java b/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/inventory/ContainerSlotEquipment.java
index 68ed1eb2..99f8b39d 100644
--- a/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/inventory/ContainerSlotEquipment.java
+++ b/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/inventory/ContainerSlotEquipment.java
@@ -19,11 +19,11 @@ class ContainerSlotEquipment extends ContainerSlotList {
   ContainerSlotEquipment(ServerPlayer holder, int index, EquipmentSlot equipmentSlot) {
     super(holder, index, InventoryType.SlotType.ARMOR);
     placeholder = switch (equipmentSlot) {
-      case HEAD -> PlaceholderManager.emptyHelmet;
-      case CHEST -> PlaceholderManager.emptyChestplate;
-      case LEGS -> PlaceholderManager.emptyLeggings;
-      case FEET -> PlaceholderManager.emptyBoots;
-      default -> PlaceholderManager.emptyOffHand;
+      case HEAD -> Placeholders.emptyHelmet;
+      case CHEST -> Placeholders.emptyChestplate;
+      case LEGS -> Placeholders.emptyLeggings;
+      case FEET -> Placeholders.emptyBoots;
+      default -> Placeholders.emptyOffHand;
     };
     this.equipmentSlot = equipmentSlot;
   }
diff --git a/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/inventory/ContainerSlotUninteractable.java b/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/inventory/ContainerSlotUninteractable.java
index f27579c8..48b57709 100644
--- a/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/inventory/ContainerSlotUninteractable.java
+++ b/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/inventory/ContainerSlotUninteractable.java
@@ -64,11 +64,13 @@ static class SlotUninteractable extends MenuSlotPlaceholder {
 
     @Override
     ItemStack getOrDefault() {
-      return PlaceholderManager.notSlot;
+      return Placeholders.notSlot;
     }
 
+    @Override
     public void onQuickCraft(ItemStack var0, ItemStack var1) {}
 
+    @Override
     public void onTake(Player var0, ItemStack var1) {}
 
     @Override
@@ -76,6 +78,7 @@ public boolean mayPlace(ItemStack var0) {
       return false;
     }
 
+    @Override
     public ItemStack getItem() {
       return ItemStack.EMPTY;
     }
@@ -85,22 +88,29 @@ public boolean hasItem() {
       return false;
     }
 
+    @Override
     public void setByPlayer(ItemStack newStack) {}
 
+    @Override
     public void setByPlayer(ItemStack newStack, ItemStack oldStack) {}
 
+    @Override
     public void set(ItemStack var0) {}
 
+    @Override
     public void setChanged() {}
 
+    @Override
     public int getMaxStackSize() {
       return 0;
     }
 
+    @Override
     public int getMaxStackSize(ItemStack itemStack) {
       return 0;
     }
 
+    @Override
     public ItemStack remove(int amount) {
       return ItemStack.EMPTY;
     }
@@ -110,22 +120,27 @@ public boolean mayPickup(Player var0) {
       return false;
     }
 
+    @Override
     public boolean isActive() {
       return false;
     }
 
+    @Override
     public Optional<ItemStack> tryRemove(int var0, int var1, Player var2) {
       return Optional.empty();
     }
 
+    @Override
     public ItemStack safeTake(int var0, int var1, Player var2) {
       return ItemStack.EMPTY;
     }
 
+    @Override
     public ItemStack safeInsert(ItemStack itemStack) {
       return itemStack;
     }
 
+    @Override
     public ItemStack safeInsert(ItemStack itemStack, int amount) {
       return itemStack;
     }
@@ -135,10 +150,12 @@ public boolean allowModification(Player var0) {
       return false;
     }
 
+    @Override
     public int getContainerSlot() {
       return this.slot;
     }
 
+    @Override
     public boolean isHighlightable() {
       return false;
     }
diff --git a/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/inventory/OpenInventory.java b/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/inventory/OpenInventory.java
index ab0336d5..5bdea862 100644
--- a/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/inventory/OpenInventory.java
+++ b/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/inventory/OpenInventory.java
@@ -1,7 +1,7 @@
 package com.lishid.openinv.internal.v1_21_R1.inventory;
 
 import com.lishid.openinv.internal.ISpecialPlayerInventory;
-import com.lishid.openinv.internal.v1_21_R1.PlayerDataManager;
+import com.lishid.openinv.internal.v1_21_R1.PlayerManager;
 import net.minecraft.ChatFormatting;
 import net.minecraft.core.NonNullList;
 import net.minecraft.network.chat.Component;
@@ -38,7 +38,7 @@ public class OpenInventory implements Container, Nameable, MenuProvider, ISpecia
   public List<HumanEntity> transaction = new ArrayList<>();
 
   public OpenInventory(@NotNull org.bukkit.entity.Player bukkitPlayer) {
-    owner = PlayerDataManager.getHandle(bukkitPlayer);
+    owner = PlayerManager.getHandle(bukkitPlayer);
 
     // Get total size, rounding up to nearest 9 for client compatibility.
     int rawSize = owner.getInventory().getContainerSize() + owner.inventoryMenu.getCraftSlots().getContainerSize() + 1;
@@ -175,7 +175,7 @@ public Slot asMenuSlot(Container container, int index, int x, int y) {
           return new SlotUninteractable(container, index, x, y) {
             @Override
             ItemStack getOrDefault() {
-              return PlaceholderManager.craftingOutput;
+              return Placeholders.craftingOutput;
             }
           };
         }
@@ -201,7 +201,7 @@ public ServerPlayer getOwnerHandle() {
   public @NotNull Component getTitle(@Nullable ServerPlayer viewer) {
     MutableComponent component = Component.empty();
     // Prefix for use with custom bitmap image fonts.
-    if (viewer == owner) {
+    if (owner.equals(viewer)) {
       component.append(
           Component.translatableWithFallback("openinv.container.inventory.self", "")
               .withStyle(style -> style
@@ -230,7 +230,7 @@ public ServerPlayer getOwnerHandle() {
 
   @Override
   public void setPlayerOnline(@NotNull org.bukkit.entity.Player player) {
-    ServerPlayer newOwner = PlayerDataManager.getHandle(player);
+    ServerPlayer newOwner = PlayerManager.getHandle(player);
     // Only transfer regular inventory - crafting and cursor slots are transient.
     newOwner.getInventory().replaceWith(owner.getInventory());
     owner = newOwner;
diff --git a/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/inventory/OpenInventoryMenu.java b/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/inventory/OpenInventoryMenu.java
index 2cad157e..a0eef7ff 100644
--- a/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/inventory/OpenInventoryMenu.java
+++ b/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/inventory/OpenInventoryMenu.java
@@ -190,6 +190,7 @@ public InventoryType.SlotType getSlotType(int slot) {
   private ItemStack remoteCarried = ItemStack.EMPTY;
   private boolean suppressRemoteUpdates;
 
+  @Override
   protected Slot addSlot(Slot slot) {
     slot.index = this.slots.size();
     this.slots.add(slot);
@@ -198,18 +199,21 @@ protected Slot addSlot(Slot slot) {
     return slot;
   }
 
+  @Override
   protected DataSlot addDataSlot(DataSlot dataSlot) {
     this.dataSlots.add(dataSlot);
     this.remoteDataSlots.add(0);
     return dataSlot;
   }
 
+  @Override
   protected void addDataSlots(ContainerData containerData) {
     for (int i = 0; i < containerData.getCount(); i++) {
       this.addDataSlot(DataSlot.forContainer(containerData, i));
     }
   }
 
+  @Override
   public void addSlotListener(ContainerListener containerListener) {
     if (!this.containerListeners.contains(containerListener)) {
       this.containerListeners.add(containerListener);
@@ -217,11 +221,13 @@ public void addSlotListener(ContainerListener containerListener) {
     }
   }
 
+  @Override
   public void setSynchronizer(ContainerSynchronizer containerSynchronizer) {
     this.synchronizer = containerSynchronizer;
     this.sendAllDataToRemote();
   }
 
+  @Override
   public void sendAllDataToRemote() {
     for (int index = 0; index < slots.size(); ++index) {
       Slot slot = slots.get(index);
@@ -239,6 +245,7 @@ public void sendAllDataToRemote() {
     }
   }
 
+  @Override
   public void broadcastCarriedItem() {
     this.remoteCarried = this.getCarried().copy();
     if (this.synchronizer != null) {
@@ -246,10 +253,12 @@ public void broadcastCarriedItem() {
     }
   }
 
+  @Override
   public void removeSlotListener(ContainerListener containerListener) {
     this.containerListeners.remove(containerListener);
   }
 
+  @Override
   public void broadcastChanges() {
     for (int index = 0; index < this.slots.size(); ++index) {
       Slot slot = this.slots.get(index);
@@ -272,6 +281,7 @@ public void broadcastChanges() {
     }
   }
 
+  @Override
   public void broadcastFullState() {
     for (int index = 0; index < this.slots.size(); ++index) {
       ItemStack itemstack = this.slots.get(index).getItem();
@@ -340,14 +350,17 @@ private void synchronizeCarriedToRemote() {
     }
   }
 
+  @Override
   public void setRemoteCarried(ItemStack itemstack) {
     this.remoteCarried = itemstack.copy();
   }
 
+  @Override
   public void suppressRemoteUpdates() {
     this.suppressRemoteUpdates = true;
   }
 
+  @Override
   public void resumeRemoteUpdates() {
     this.suppressRemoteUpdates = false;
   }
@@ -429,6 +442,7 @@ public boolean stillValid(Player player) {
    * @param topDown whether to start at the top of the range or bottom
    * @return whether the stack was modified as a result of being quick-moved
    */
+  @Override
   protected boolean moveItemStackTo(ItemStack itemStack, int rangeLow, int rangeHigh, boolean topDown) {
     boolean modified = false;
     boolean stackable = itemStack.isStackable();
diff --git a/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/inventory/PlaceholderManager.java b/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/inventory/Placeholders.java
similarity index 96%
rename from internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/inventory/PlaceholderManager.java
rename to internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/inventory/Placeholders.java
index 9a594460..48b91ba7 100644
--- a/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/inventory/PlaceholderManager.java
+++ b/internal/v1_21_R1/src/main/java/com/lishid/openinv/internal/v1_21_R1/inventory/Placeholders.java
@@ -1,6 +1,5 @@
 package com.lishid.openinv.internal.v1_21_R1.inventory;
 
-import com.lishid.openinv.internal.PlaceholderParser;
 import net.minecraft.core.Registry;
 import net.minecraft.core.RegistryAccess;
 import net.minecraft.core.component.DataComponents;
@@ -28,7 +27,7 @@
 import java.util.List;
 import java.util.Optional;
 
-public class PlaceholderManager implements PlaceholderParser {
+public final class Placeholders {
 
   private static final CustomModelData DEFAULT_CUSTOM_MODEL_DATA = new CustomModelData(9999);
   static final @NotNull EnumMap<GameType, ItemStack> BLOCKED_GAME_TYPE = new EnumMap<>(GameType.class);
@@ -54,8 +53,7 @@ public class PlaceholderManager implements PlaceholderParser {
     }
   }
 
-  @Override
-  public void load(@NotNull ConfigurationSection section) throws Exception {
+  public static void load(@NotNull ConfigurationSection section) throws Exception {
     craftingOutput = parse(section, "crafting-output", craftingOutput);
     cursor = parse(section, "cursor", cursor);
     drop = parse(section, "drop", drop);
@@ -70,7 +68,7 @@ public void load(@NotNull ConfigurationSection section) throws Exception {
     BLOCKED_GAME_TYPE.put(GameType.SPECTATOR, parse(section, "blocked.spectator", BLOCKED_GAME_TYPE.get(GameType.SPECTATOR)));
   }
 
-  private @NotNull ItemStack parse(
+  private static @NotNull ItemStack parse(
       @NotNull ConfigurationSection section,
       @NotNull String path,
       @NotNull ItemStack defaultStack) throws Exception {
@@ -178,4 +176,8 @@ private static ItemStack defaultBlockedOffline() {
     return itemStack;
   }
 
+  private Placeholders() {
+    throw new IllegalStateException("Cannot create instance of utility class.");
+  }
+
 }
diff --git a/plugin/pom.xml b/plugin/pom.xml
index 2a7b9df6..381a5018 100644
--- a/plugin/pom.xml
+++ b/plugin/pom.xml
@@ -24,29 +24,52 @@
     <version>5.0.0-SNAPSHOT</version>
   </parent>
 
-  <artifactId>openinvplugincore</artifactId>
+  <artifactId>openinvplugin</artifactId>
   <name>OpenInvPlugin</name>
 
   <dependencies>
+    <dependency>
+      <artifactId>spigot-api</artifactId>
+      <groupId>org.spigotmc</groupId>
+    </dependency>
+    <dependency>
+      <artifactId>planarwrappers</artifactId>
+      <groupId>com.github.jikoo</groupId>
+    </dependency>
     <dependency>
       <artifactId>openinvapi</artifactId>
       <groupId>com.lishid</groupId>
     </dependency>
     <dependency>
-      <artifactId>annotations</artifactId>
-      <groupId>org.jetbrains</groupId>
+      <artifactId>openinvcommon</artifactId>
+      <groupId>com.lishid</groupId>
     </dependency>
     <dependency>
-      <artifactId>spigot-api</artifactId>
-      <groupId>org.spigotmc</groupId>
+      <groupId>com.lishid</groupId>
+      <artifactId>openinvadapter1_21_R1</artifactId>
+      <version>5.0.0-SNAPSHOT</version>
+      <scope>compile</scope>
     </dependency>
     <dependency>
-      <artifactId>planarwrappers</artifactId>
-      <groupId>com.github.jikoo</groupId>
+      <groupId>com.lishid</groupId>
+      <artifactId>openinvadapter1_20_R4</artifactId>
+      <version>5.0.0-SNAPSHOT</version>
+      <scope>compile</scope>
+    </dependency>
+    <dependency>
+      <groupId>com.lishid</groupId>
+      <artifactId>openinvadapter1_20_R3</artifactId>
+      <version>5.0.0-SNAPSHOT</version>
+      <scope>compile</scope>
+    </dependency>
+    <dependency>
+      <artifactId>annotations</artifactId>
+      <groupId>org.jetbrains</groupId>
     </dependency>
   </dependencies>
 
   <build>
+    <finalName>OpenInv</finalName>
     <resources>
       <resource>
         <directory>src/main/resources</directory>
@@ -86,6 +109,29 @@
       <plugin>
         <artifactId>maven-compiler-plugin</artifactId>
       </plugin>
+      <plugin>
+        <artifactId>maven-resources-plugin</artifactId>
+        <executions>
+          <execution>
+            <id>copy-final-jar</id>
+            <phase>package</phase>
+            <goals>
+              <goal>copy-resources</goal>
+            </goals>
+            <configuration>
+              <outputDirectory>${project.parent.build.directory}</outputDirectory>
+              <resources>
+                <resource>
+                  <directory>${project.build.directory}</directory>
+                  <includes>
+                    <include>${project.build.finalName}.jar</include>
+                  </includes>
+                </resource>
+              </resources>
+            </configuration>
+          </execution>
+        </executions>
+      </plugin>
     </plugins>
   </build>
 
diff --git a/plugin/src/main/java/com/lishid/openinv/InventoryListener.java b/plugin/src/main/java/com/lishid/openinv/InventoryListener.java
index 0e425fb1..390277b2 100644
--- a/plugin/src/main/java/com/lishid/openinv/InventoryListener.java
+++ b/plugin/src/main/java/com/lishid/openinv/InventoryListener.java
@@ -16,6 +16,7 @@
 
 package com.lishid.openinv;
 
+import com.google.errorprone.annotations.Keep;
 import com.lishid.openinv.internal.ISpecialEnderChest;
 import com.lishid.openinv.internal.ISpecialInventory;
 import com.lishid.openinv.internal.ISpecialPlayerInventory;
@@ -44,6 +45,7 @@
  */
 record InventoryListener(OpenInv plugin) implements Listener {
 
+    @Keep
     @EventHandler
     private void onInventoryClose(@NotNull final InventoryCloseEvent event) {
         if (!(event.getPlayer() instanceof Player player)) {
@@ -68,11 +70,13 @@ private void onInventoryClose(@NotNull final InventoryCloseEvent event) {
         }
     }
 
+    @Keep
     @EventHandler(priority = EventPriority.LOWEST)
     private void onInventoryClick(@NotNull final InventoryClickEvent event) {
         handleInventoryInteract(event);
     }
 
+    @Keep
     @EventHandler(priority = EventPriority.LOWEST)
     private void onInventoryDrag(@NotNull final InventoryDragEvent event) {
         handleInventoryInteract(event);
diff --git a/plugin/src/main/java/com/lishid/openinv/LegacyInventoryListener.java b/plugin/src/main/java/com/lishid/openinv/LegacyInventoryListener.java
index 9e49ca54..a92c92e6 100644
--- a/plugin/src/main/java/com/lishid/openinv/LegacyInventoryListener.java
+++ b/plugin/src/main/java/com/lishid/openinv/LegacyInventoryListener.java
@@ -1,5 +1,6 @@
 package com.lishid.openinv;
 
+import com.google.errorprone.annotations.Keep;
 import com.lishid.openinv.internal.ISpecialEnderChest;
 import com.lishid.openinv.internal.ISpecialInventory;
 import com.lishid.openinv.internal.ISpecialPlayerInventory;
@@ -30,6 +31,7 @@
 
 record LegacyInventoryListener(OpenInv plugin) implements Listener {
 
+  @Keep
   @EventHandler
   private void onInventoryClose(@NotNull final InventoryCloseEvent event) {
     if (!(event.getPlayer() instanceof Player player)) {
@@ -54,6 +56,7 @@ private void onInventoryClose(@NotNull final InventoryCloseEvent event) {
     }
   }
 
+  @Keep
   @EventHandler(priority = EventPriority.LOWEST)
   private void onInventoryClick(@NotNull final InventoryClickEvent event) {
     if (handleInventoryInteract(event)) {
@@ -79,11 +82,10 @@ private void onInventoryClick(@NotNull final InventoryClickEvent event) {
     event.setCurrentItem(null);
 
     // Complete add action in same tick after event completion.
-    this.plugin.getServer().getScheduler().runTask(this.plugin, () -> {
-      player.getInventory().addItem(clone);
-    });
+    this.plugin.getServer().getScheduler().runTask(this.plugin, () -> player.getInventory().addItem(clone));
   }
 
+  @Keep
   @EventHandler(priority = EventPriority.LOWEST)
   private void onInventoryDrag(@NotNull final InventoryDragEvent event) {
     if (handleInventoryInteract(event)) {
diff --git a/plugin/src/main/java/com/lishid/openinv/OpenInv.java b/plugin/src/main/java/com/lishid/openinv/OpenInv.java
index a945e8fc..f6c9f160 100644
--- a/plugin/src/main/java/com/lishid/openinv/OpenInv.java
+++ b/plugin/src/main/java/com/lishid/openinv/OpenInv.java
@@ -25,18 +25,16 @@
 import com.lishid.openinv.commands.SearchContainerCommand;
 import com.lishid.openinv.commands.SearchEnchantCommand;
 import com.lishid.openinv.commands.SearchInvCommand;
-import com.lishid.openinv.event.OpenPlayerSaveEvent;
+import com.lishid.openinv.event.OpenEvents;
 import com.lishid.openinv.internal.IAnySilentContainer;
 import com.lishid.openinv.internal.ISpecialEnderChest;
 import com.lishid.openinv.internal.ISpecialInventory;
 import com.lishid.openinv.internal.ISpecialPlayerInventory;
 import com.lishid.openinv.util.ConfigUpdater;
+import com.lishid.openinv.util.InternalAccessor;
 import com.lishid.openinv.util.Permissions;
 import com.lishid.openinv.util.StringMetric;
 import com.lishid.openinv.util.lang.LanguageManager;
-import com.lishid.openinv.util.lang.Replacement;
-import net.md_5.bungee.api.ChatMessageType;
-import net.md_5.bungee.api.chat.TextComponent;
 import org.bukkit.Bukkit;
 import org.bukkit.OfflinePlayer;
 import org.bukkit.command.Command;
@@ -87,7 +85,7 @@ public void reloadConfig() {
         super.reloadConfig();
         this.offlineHandler = disableOfflineAccess() ? OfflineHandler.REMOVE_AND_CLOSE : OfflineHandler.REQUIRE_PERMISSIONS;
         if (this.accessor != null && this.accessor.isSupported()) {
-            this.accessor.reload();
+            this.accessor.reload(this.getConfig());
         }
     }
 
@@ -130,12 +128,8 @@ public void onEnable() {
         // Save default configuration if not present.
         this.saveDefaultConfig();
 
-        // Get plugin manager
-        PluginManager pm = this.getServer().getPluginManager();
-
-        this.accessor = new InternalAccessor(this);
-
         this.languageManager = new LanguageManager(this, "en_us");
+        this.accessor = new InternalAccessor(getLogger(), languageManager);
 
         try {
             Class.forName("org.bukkit.entity.Player$Spigot");
@@ -151,20 +145,22 @@ public void onEnable() {
             // Update existing configuration. May require internal access.
             new ConfigUpdater(this).checkForUpdates();
 
+            // Get plugin manager
+            PluginManager pm = this.getServer().getPluginManager();
             // Register listeners
             if (BukkitVersions.MINECRAFT.lessThan(Version.of(1, 21))) {
                 pm.registerEvents(new LegacyInventoryListener(this), this);
             } else {
-                pm.registerEvents(new PlayerListener(this), this);
+                pm.registerEvents(new PlayerListener(this, languageManager), this);
             }
             pm.registerEvents(new InventoryListener(this), this);
 
             // Register commands to their executors
-            this.setCommandExecutor(new OpenInvCommand(this), "openinv", "openender");
-            this.setCommandExecutor(new SearchContainerCommand(this), "searchcontainer");
-            this.setCommandExecutor(new SearchInvCommand(this), "searchinv", "searchender");
-            this.setCommandExecutor(new SearchEnchantCommand(this), "searchenchant");
-            this.setCommandExecutor(new ContainerSettingCommand(this), "silentcontainer", "anycontainer");
+            this.setCommandExecutor(new OpenInvCommand(this, languageManager), "openinv", "openender");
+            this.setCommandExecutor(new SearchContainerCommand(this, languageManager), "searchcontainer");
+            this.setCommandExecutor(new SearchInvCommand(languageManager), "searchinv", "searchender");
+            this.setCommandExecutor(new SearchEnchantCommand(languageManager), "searchenchant");
+            this.setCommandExecutor(new ContainerSettingCommand(this, languageManager), "silentcontainer", "anycontainer");
 
         } else {
             this.sendVersionError(this.getLogger()::warning);
@@ -182,9 +178,15 @@ private void setCommandExecutor(@NotNull CommandExecutor executor, String @NotNu
     }
 
     private void sendVersionError(@NotNull Consumer<String> messageMethod) {
-        if (!this.accessor.isSupported()) {
-            messageMethod.accept("Your server version (" + this.accessor.getVersion() + ") is not supported.");
-            messageMethod.accept("Please download the correct version of OpenInv here: " + this.accessor.getReleasesLink());
+        if (!accessor.isSupported()) {
+            messageMethod.accept("Your server version (" + accessor.getVersion() + ") is not supported.");
+            messageMethod.accept("Please download the correct version of OpenInv here: " + accessor.getReleasesLink());
+
+            // We check this property late so users can use jars that were remapped by Paper already.
+            if (Boolean.getBoolean("paper.disable-plugin-rewriting")) {
+                messageMethod.accept("OpenInv uses Spigot-mapped internals, but you have disabled plugin rewriting in Paper!");
+                messageMethod.accept("Please set system property 'paper.disable-plugin-rewriting' to false.");
+            }
         }
         if (!isSpigot) {
             messageMethod.accept("OpenInv requires that you use Spigot or a Spigot fork. Per the 1.14 update thread");
@@ -242,22 +244,20 @@ public void setSilentContainerStatus(@NotNull final OfflinePlayer offline, final
     }
 
     @Override
-    public @NotNull ISpecialEnderChest getSpecialEnderChest(@NotNull final Player player, final boolean online)
-            throws InstantiationException {
+    public @NotNull ISpecialEnderChest getSpecialEnderChest(@NotNull final Player player, final boolean online) {
         UUID key = player.getUniqueId();
 
         if (this.enderChests.containsKey(key)) {
             return this.enderChests.get(key);
         }
 
-        ISpecialEnderChest inv = this.accessor.newSpecialEnderChest(player, online);
+        ISpecialEnderChest inv = this.accessor.newSpecialEnderChest(player);
         this.enderChests.put(key, inv);
         return inv;
     }
 
     @Override
-    public @NotNull ISpecialPlayerInventory getSpecialInventory(@NotNull final Player player, final boolean online)
-            throws InstantiationException {
+    public @NotNull ISpecialPlayerInventory getSpecialInventory(@NotNull final Player player, final boolean online) {
         UUID key = player.getUniqueId();
 
         if (this.inventories.containsKey(key)) {
@@ -436,61 +436,6 @@ private void kickCrossWorldViewers(@NotNull Player player, @NotNull ISpecialInve
                                 && !Objects.equals(viewer.getWorld(), player.getWorld()));
     }
 
-    public @Nullable String getLocalizedMessage(@NotNull CommandSender sender, @NotNull String key) {
-        return this.languageManager.getValue(key, getLocale(sender));
-    }
-
-    public @Nullable String getLocalizedMessage(
-            @NotNull CommandSender sender,
-            @NotNull String key,
-            Replacement @NotNull ... replacements) {
-        return this.languageManager.getValue(key, getLocale(sender), replacements);
-    }
-
-    private @NotNull String getLocale(@NotNull CommandSender sender) {
-        if (sender instanceof Player) {
-            return ((Player) sender).getLocale();
-        } else {
-            return this.getConfig().getString("settings.locale", "en_us");
-        }
-    }
-
-    public void sendMessage(@NotNull CommandSender sender, @NotNull String key) {
-        String message = getLocalizedMessage(sender, key);
-
-        if (message != null && !message.isEmpty()) {
-            sender.sendMessage(message);
-        }
-    }
-
-    public void sendMessage(@NotNull CommandSender sender, @NotNull String key, Replacement @NotNull... replacements) {
-        String message = getLocalizedMessage(sender, key, replacements);
-
-        if (message != null && !message.isEmpty()) {
-            sender.sendMessage(message);
-        }
-    }
-
-    public void sendSystemMessage(@NotNull Player player, @NotNull String key) {
-        String message = getLocalizedMessage(player, key);
-
-        if (message == null) {
-            return;
-        }
-
-        int newline = message.indexOf('\n');
-        if (newline != -1) {
-            // No newlines in action bar chat.
-            message = message.substring(0, newline);
-        }
-
-        if (message.isEmpty()) {
-            return;
-        }
-
-        player.spigot().sendMessage(ChatMessageType.ACTION_BAR, TextComponent.fromLegacy(message));
-    }
-
     /**
      * Method for handling a Player going offline.
      *
@@ -562,10 +507,7 @@ void handleCloseInventory(@NotNull ISpecialInventory inventory) {
                 return;
             }
 
-            OpenPlayerSaveEvent event = new OpenPlayerSaveEvent(player, current);
-            getServer().getPluginManager().callEvent(event);
-
-            if (!event.isCancelled()) {
+            if (!OpenEvents.saveCancelled(player, current)) {
                 this.accessor.getPlayerDataManager().inject(player).saveData();
             }
         });
@@ -638,8 +580,8 @@ private void setPlayerOnline(
                 inventory,
                 viewer ->
                         !Permissions.ACCESS_ONLINE.hasPermission(viewer)
-                                || !Permissions.ACCESS_CROSSWORLD.hasPermission(viewer)
-                                && !Objects.equals(viewer.getWorld(), inventory.getPlayer().getWorld()));
+                                || (!Permissions.ACCESS_CROSSWORLD.hasPermission(viewer)
+                                        && !Objects.equals(viewer.getWorld(), inventory.getPlayer().getWorld())));
     }
 
     static void ejectViewers(@NotNull ISpecialInventory inventory, @NotNull Predicate<@NotNull HumanEntity> predicate) {
diff --git a/plugin/src/main/java/com/lishid/openinv/PlayerListener.java b/plugin/src/main/java/com/lishid/openinv/PlayerListener.java
index 64ad0592..ddf868ad 100644
--- a/plugin/src/main/java/com/lishid/openinv/PlayerListener.java
+++ b/plugin/src/main/java/com/lishid/openinv/PlayerListener.java
@@ -16,7 +16,9 @@
 
 package com.lishid.openinv;
 
+import com.google.errorprone.annotations.Keep;
 import com.lishid.openinv.util.Permissions;
+import com.lishid.openinv.util.lang.LanguageManager;
 import org.bukkit.entity.Player;
 import org.bukkit.event.Event.Result;
 import org.bukkit.event.EventHandler;
@@ -29,23 +31,35 @@
 import org.bukkit.event.player.PlayerQuitEvent;
 import org.jetbrains.annotations.NotNull;
 
-record PlayerListener(OpenInv plugin) implements Listener {
+class PlayerListener implements Listener {
 
+    private final @NotNull OpenInv plugin;
+    private final @NotNull LanguageManager lang;
+
+  PlayerListener(@NotNull OpenInv plugin, @NotNull LanguageManager lang) {
+    this.plugin = plugin;
+    this.lang = lang;
+  }
+
+  @Keep
     @EventHandler(priority = EventPriority.LOWEST)
     private void onPlayerJoin(@NotNull PlayerJoinEvent event) {
         plugin.setPlayerOnline(event.getPlayer());
     }
 
+    @Keep
     @EventHandler(priority = EventPriority.MONITOR)
     private void onPlayerQuit(@NotNull PlayerQuitEvent event) {
         plugin.setPlayerOffline(event.getPlayer());
     }
 
+    @Keep
     @EventHandler
     private void onWorldChange(@NotNull PlayerChangedWorldEvent event) {
         plugin.changeWorld(event.getPlayer());
     }
 
+    @Keep
     @EventHandler(priority = EventPriority.MONITOR, ignoreCancelled = true)
     private void onPlayerInteract(@NotNull PlayerInteractEvent event) {
 
@@ -74,11 +88,11 @@ private void onPlayerInteract(@NotNull PlayerInteractEvent event) {
         if (any || silent) {
             if (plugin.getAnySilentContainer().activateContainer(player, silent, event.getClickedBlock())) {
                 if (silent && needsAny) {
-                    plugin.sendSystemMessage(player, "messages.info.containerBlockedSilent");
+                    lang.sendSystemMessage(player, "messages.info.containerBlockedSilent");
                 } else if (needsAny) {
-                    plugin.sendSystemMessage(player, "messages.info.containerBlocked");
+                    lang.sendSystemMessage(player, "messages.info.containerBlocked");
                 } else if (silent) {
-                    plugin.sendSystemMessage(player, "messages.info.containerSilent");
+                    lang.sendSystemMessage(player, "messages.info.containerSilent");
                 }
             }
             event.setCancelled(true);
diff --git a/plugin/src/main/java/com/lishid/openinv/commands/ContainerSettingCommand.java b/plugin/src/main/java/com/lishid/openinv/commands/ContainerSettingCommand.java
index c8dd3c7d..02e5b759 100644
--- a/plugin/src/main/java/com/lishid/openinv/commands/ContainerSettingCommand.java
+++ b/plugin/src/main/java/com/lishid/openinv/commands/ContainerSettingCommand.java
@@ -16,13 +16,10 @@
 
 package com.lishid.openinv.commands;
 
-import com.lishid.openinv.OpenInv;
+import com.lishid.openinv.IOpenInv;
 import com.lishid.openinv.util.TabCompleter;
+import com.lishid.openinv.util.lang.LanguageManager;
 import com.lishid.openinv.util.lang.Replacement;
-import java.util.Collections;
-import java.util.List;
-import java.util.function.BiConsumer;
-import java.util.function.Predicate;
 import org.bukkit.OfflinePlayer;
 import org.bukkit.command.Command;
 import org.bukkit.command.CommandSender;
@@ -30,18 +27,26 @@
 import org.bukkit.entity.Player;
 import org.jetbrains.annotations.NotNull;
 
+import java.util.Collections;
+import java.util.List;
+import java.util.Locale;
+import java.util.function.BiConsumer;
+import java.util.function.Predicate;
+
 public class ContainerSettingCommand implements TabExecutor {
 
-    private final OpenInv plugin;
+    private final @NotNull IOpenInv plugin;
+    private final @NotNull LanguageManager lang;
 
-    public ContainerSettingCommand(final OpenInv plugin) {
+    public ContainerSettingCommand(@NotNull IOpenInv plugin, @NotNull LanguageManager lang) {
         this.plugin = plugin;
+        this.lang = lang;
     }
 
     @Override
     public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label, @NotNull String[] args) {
         if (!(sender instanceof Player player)) {
-            plugin.sendMessage(sender, "messages.error.consoleUnsupported");
+            lang.sendMessage(sender, "messages.error.consoleUnsupported");
             return true;
         }
 
@@ -50,7 +55,7 @@ public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command
         BiConsumer<OfflinePlayer, Boolean> setSetting = any ? plugin::setAnyContainerStatus : plugin::setSilentContainerStatus;
 
         if (args.length > 0) {
-            args[0] = args[0].toLowerCase();
+            args[0] = args[0].toLowerCase(Locale.ENGLISH);
 
             if (args[0].equals("on")) {
                 setSetting.accept(player, true);
@@ -65,12 +70,12 @@ public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command
             setSetting.accept(player, !getSetting.test(player));
         }
 
-        String onOff = plugin.getLocalizedMessage(player, getSetting.test(player) ? "messages.info.on" : "messages.info.off");
+        String onOff = lang.getLocalizedMessage(player, getSetting.test(player) ? "messages.info.on" : "messages.info.off");
         if (onOff == null) {
             onOff = String.valueOf(getSetting.test(player));
         }
 
-        plugin.sendMessage(
+        lang.sendMessage(
                 sender,
                 "messages.info.settingState",
                 new Replacement("%setting%", any ? "AnyContainer" : "SilentContainer"),
diff --git a/plugin/src/main/java/com/lishid/openinv/commands/OpenInvCommand.java b/plugin/src/main/java/com/lishid/openinv/commands/OpenInvCommand.java
index fba649e7..f082c959 100644
--- a/plugin/src/main/java/com/lishid/openinv/commands/OpenInvCommand.java
+++ b/plugin/src/main/java/com/lishid/openinv/commands/OpenInvCommand.java
@@ -20,6 +20,7 @@
 import com.lishid.openinv.internal.ISpecialInventory;
 import com.lishid.openinv.util.Permissions;
 import com.lishid.openinv.util.TabCompleter;
+import com.lishid.openinv.util.lang.LanguageManager;
 import com.lishid.openinv.util.lang.Replacement;
 import org.bukkit.OfflinePlayer;
 import org.bukkit.command.Command;
@@ -38,12 +39,14 @@
 
 public class OpenInvCommand implements TabExecutor {
 
-    private final OpenInv plugin;
+    private final @NotNull OpenInv plugin;
+    private final @NotNull LanguageManager lang;
     private final HashMap<Player, String> openInvHistory = new HashMap<>();
     private final HashMap<Player, String> openEnderHistory = new HashMap<>();
 
-    public OpenInvCommand(final OpenInv plugin) {
+    public OpenInvCommand(@NotNull OpenInv plugin, @NotNull LanguageManager lang) {
         this.plugin = plugin;
+        this.lang = lang;
     }
 
     @Override
@@ -56,7 +59,7 @@ public boolean onCommand(@NotNull final CommandSender sender, @NotNull final Com
         }
 
         if (!(sender instanceof Player player)) {
-            plugin.sendMessage(sender, "messages.error.consoleUnsupported");
+            lang.sendMessage(sender, "messages.error.consoleUnsupported");
             return true;
         }
 
@@ -86,8 +89,8 @@ public boolean onCommand(@NotNull final CommandSender sender, @NotNull final Com
             public void run() {
                 final OfflinePlayer offlinePlayer = OpenInvCommand.this.plugin.matchPlayer(name);
 
-                if (offlinePlayer == null || !offlinePlayer.hasPlayedBefore() && !offlinePlayer.isOnline()) {
-                    plugin.sendMessage(player, "messages.error.invalidPlayer");
+                if (offlinePlayer == null || (!offlinePlayer.hasPlayedBefore() && !offlinePlayer.isOnline())) {
+                    lang.sendMessage(player, "messages.error.invalidPlayer");
                     return;
                 }
 
@@ -144,20 +147,20 @@ private void openInventory(final Player player, final OfflinePlayer target, bool
                 // Try loading the player's data
                 onlineTarget = this.plugin.loadPlayer(target);
             } else {
-                plugin.sendMessage(player, "messages.error.permissionPlayerOffline");
+                lang.sendMessage(player, "messages.error.permissionPlayerOffline");
                 return;
             }
         } else {
             if (Permissions.ACCESS_ONLINE.hasPermission(player)) {
                 onlineTarget = target.getPlayer();
             } else {
-                plugin.sendMessage(player, "messages.error.permissionPlayerOnline");
+                lang.sendMessage(player, "messages.error.permissionPlayerOnline");
                 return;
             }
         }
 
         if (onlineTarget == null) {
-            plugin.sendMessage(player, "messages.error.invalidPlayer");
+            lang.sendMessage(player, "messages.error.invalidPlayer");
             return;
         }
 
@@ -165,14 +168,14 @@ private void openInventory(final Player player, final OfflinePlayer target, bool
         if (onlineTarget.equals(player)) {
             // Permission for opening own inventory.
             if (!(openinv ? Permissions.INVENTORY_OPEN_SELF : Permissions.ENDERCHEST_OPEN_SELF).hasPermission(player)) {
-                plugin.sendMessage(player, "messages.error.permissionOpenSelf");
+                lang.sendMessage(player, "messages.error.permissionOpenSelf");
                 return;
 
             }
         } else {
             // Permission for opening others' inventories.
             if (!(openinv ? Permissions.INVENTORY_OPEN_OTHER : Permissions.ENDERCHEST_OPEN_OTHER).hasPermission(player)) {
-                plugin.sendMessage(player, "messages.error.permissionOpenOther");
+                lang.sendMessage(player, "messages.error.permissionOpenOther");
                 return;
             }
 
@@ -181,7 +184,7 @@ private void openInventory(final Player player, final OfflinePlayer target, bool
                 String permission = "openinv.access.level." + level;
                 if (onlineTarget.hasPermission(permission)
                         && !player.hasPermission(permission)) {
-                    plugin.sendMessage(
+                    lang.sendMessage(
                         player,
                         "messages.error.permissionExempt",
                         new Replacement("%target%", onlineTarget.getDisplayName()));
@@ -192,7 +195,7 @@ private void openInventory(final Player player, final OfflinePlayer target, bool
             // Crossworld check
             if (!Permissions.ACCESS_CROSSWORLD.hasPermission(player)
                     && !onlineTarget.getWorld().equals(player.getWorld())) {
-                plugin.sendMessage(
+                lang.sendMessage(
                         player,
                         "messages.error.permissionCrossWorld",
                         new Replacement("%target%", onlineTarget.getDisplayName()));
@@ -210,7 +213,7 @@ private void openInventory(final Player player, final OfflinePlayer target, bool
         try {
             inv = openinv ? this.plugin.getSpecialInventory(onlineTarget, online) : this.plugin.getSpecialEnderChest(onlineTarget, online);
         } catch (Exception e) {
-            plugin.sendMessage(player, "messages.error.commandException");
+            lang.sendMessage(player, "messages.error.commandException");
             plugin.getLogger().log(Level.WARNING, "Unable to create ISpecialInventory", e);
             return;
         }
diff --git a/plugin/src/main/java/com/lishid/openinv/commands/SearchContainerCommand.java b/plugin/src/main/java/com/lishid/openinv/commands/SearchContainerCommand.java
index b524b2f9..fd61fc22 100644
--- a/plugin/src/main/java/com/lishid/openinv/commands/SearchContainerCommand.java
+++ b/plugin/src/main/java/com/lishid/openinv/commands/SearchContainerCommand.java
@@ -16,11 +16,9 @@
 
 package com.lishid.openinv.commands;
 
-import com.lishid.openinv.OpenInv;
 import com.lishid.openinv.util.TabCompleter;
+import com.lishid.openinv.util.lang.LanguageManager;
 import com.lishid.openinv.util.lang.Replacement;
-import java.util.Collections;
-import java.util.List;
 import org.bukkit.Chunk;
 import org.bukkit.Material;
 import org.bukkit.World;
@@ -30,23 +28,30 @@
 import org.bukkit.command.TabExecutor;
 import org.bukkit.entity.Player;
 import org.bukkit.inventory.InventoryHolder;
+import org.bukkit.plugin.Plugin;
 import org.jetbrains.annotations.NotNull;
 
+import java.util.Collections;
+import java.util.List;
+import java.util.Locale;
+
 /**
  * Command for searching containers in a radius of chunks.
  */
 public class SearchContainerCommand implements TabExecutor {
 
-    private final OpenInv plugin;
+    private final @NotNull Plugin plugin;
+    private final @NotNull LanguageManager lang;
 
-    public SearchContainerCommand(OpenInv plugin) {
+    public SearchContainerCommand(@NotNull Plugin plugin, @NotNull LanguageManager lang) {
         this.plugin = plugin;
+        this.lang = lang;
     }
 
     @Override
     public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label, @NotNull String[] args) {
         if (!(sender instanceof Player senderPlayer)) {
-            plugin.sendMessage(sender, "messages.error.consoleUnsupported");
+            lang.sendMessage(sender, "messages.error.consoleUnsupported");
             return true;
         }
 
@@ -55,10 +60,10 @@ public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command
             return false;
         }
 
-        Material material = Material.getMaterial(args[0].toUpperCase());
+        Material material = Material.matchMaterial(args[0]);
 
         if (material == null) {
-            plugin.sendMessage(
+            lang.sendMessage(
                     sender,
                     "messages.error.invalidMaterial",
                     new Replacement("%target%", args[0]));
@@ -97,7 +102,7 @@ public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command
                     if (!holder.getInventory().contains(material)) {
                         continue;
                     }
-                    locations.append(holder.getInventory().getType().name().toLowerCase()).append(" (")
+                    locations.append(holder.getInventory().getType().name().toLowerCase(Locale.ENGLISH)).append(" (")
                             .append(tileEntity.getX()).append(',').append(tileEntity.getY()).append(',')
                             .append(tileEntity.getZ()).append("), ");
                 }
@@ -108,14 +113,14 @@ public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command
         if (!locations.isEmpty()) {
             locations.delete(locations.length() - 2, locations.length());
         } else {
-            plugin.sendMessage(
+            lang.sendMessage(
                     sender,
                     "messages.info.container.noMatches",
                     new Replacement("%target%", material.name()));
             return true;
         }
 
-        plugin.sendMessage(
+        lang.sendMessage(
                 sender,
                 "messages.info.container.matches",
                 new Replacement("%target%", material.name()),
diff --git a/plugin/src/main/java/com/lishid/openinv/commands/SearchEnchantCommand.java b/plugin/src/main/java/com/lishid/openinv/commands/SearchEnchantCommand.java
index 8abaec9e..3e66acca 100644
--- a/plugin/src/main/java/com/lishid/openinv/commands/SearchEnchantCommand.java
+++ b/plugin/src/main/java/com/lishid/openinv/commands/SearchEnchantCommand.java
@@ -16,9 +16,10 @@
 
 package com.lishid.openinv.commands;
 
-import com.lishid.openinv.OpenInv;
 import com.lishid.openinv.util.TabCompleter;
+import com.lishid.openinv.util.lang.LanguageManager;
 import com.lishid.openinv.util.lang.Replacement;
+import org.bukkit.Bukkit;
 import org.bukkit.Material;
 import org.bukkit.NamespacedKey;
 import org.bukkit.Registry;
@@ -35,6 +36,7 @@
 
 import java.util.Collections;
 import java.util.List;
+import java.util.Locale;
 
 /**
  * Command adding the ability to search online players' inventories for enchantments of a specific
@@ -44,10 +46,10 @@
  */
 public class SearchEnchantCommand implements TabExecutor {
 
-    private final OpenInv plugin;
+    private final LanguageManager lang;
 
-    public SearchEnchantCommand(OpenInv plugin) {
-        this.plugin = plugin;
+    public SearchEnchantCommand(LanguageManager lang) {
+        this.lang = lang;
     }
 
     @Override
@@ -63,9 +65,11 @@ public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command
             try {
                 level = Integer.parseInt(argument);
                 continue;
-            } catch (NumberFormatException ignored) {}
+            } catch (NumberFormatException ignored) {
+                // Not a level being specified.
+            }
 
-            argument = argument.toLowerCase();
+            argument = argument.toLowerCase(Locale.ENGLISH);
             NamespacedKey key = NamespacedKey.fromString(argument);
             if (key == null) {
                 continue;
@@ -83,7 +87,7 @@ public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command
         }
 
         StringBuilder players = new StringBuilder();
-        for (Player player : plugin.getServer().getOnlinePlayers()) {
+        for (Player player : Bukkit.getServer().getOnlinePlayers()) {
             boolean flagInventory = containsEnchantment(player.getInventory(), enchant, level);
             boolean flagEnder = containsEnchantment(player.getEnderChest(), enchant, level);
 
@@ -110,14 +114,14 @@ public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command
             // Matches found, delete trailing comma and space
             players.delete(players.length() - 2, players.length());
         } else {
-            plugin.sendMessage(
+            lang.sendMessage(
                     sender,
                     "messages.info.player.noMatches",
                     new Replacement("%target%", (enchant != null ? enchant.getKey().toString() : "") + " >= " + level));
             return true;
         }
 
-        plugin.sendMessage(
+        lang.sendMessage(
                 sender,
                 "messages.info.player.matches",
                 new Replacement("%target%", (enchant != null ? enchant.getKey().toString() : "") + " >= " + level),
diff --git a/plugin/src/main/java/com/lishid/openinv/commands/SearchInvCommand.java b/plugin/src/main/java/com/lishid/openinv/commands/SearchInvCommand.java
index f40588c5..234d4ead 100644
--- a/plugin/src/main/java/com/lishid/openinv/commands/SearchInvCommand.java
+++ b/plugin/src/main/java/com/lishid/openinv/commands/SearchInvCommand.java
@@ -16,9 +16,10 @@
 
 package com.lishid.openinv.commands;
 
-import com.lishid.openinv.OpenInv;
 import com.lishid.openinv.util.TabCompleter;
+import com.lishid.openinv.util.lang.LanguageManager;
 import com.lishid.openinv.util.lang.Replacement;
+import org.bukkit.Bukkit;
 import org.bukkit.Material;
 import org.bukkit.command.Command;
 import org.bukkit.command.CommandSender;
@@ -33,10 +34,10 @@
 
 public class SearchInvCommand implements TabExecutor {
 
-    private final OpenInv plugin;
+    private final LanguageManager lang;
 
-    public SearchInvCommand(OpenInv plugin) {
-        this.plugin = plugin;
+    public SearchInvCommand(LanguageManager lang) {
+        this.lang = lang;
     }
 
     @Override
@@ -45,11 +46,11 @@ public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command
         Material material = null;
 
         if (args.length >= 1) {
-            material = Material.getMaterial(args[0].toUpperCase());
+            material = Material.matchMaterial(args[0]);
         }
 
         if (material == null) {
-            plugin.sendMessage(
+            lang.sendMessage(
                     sender,
                     "messages.error.invalidMaterial",
                     new Replacement("%target%", args.length > 0 ? args[0] : "null"));
@@ -62,7 +63,7 @@ public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command
             try {
                 count = Integer.parseInt(args[1]);
             } catch (NumberFormatException ex) {
-                plugin.sendMessage(
+                lang.sendMessage(
                         sender,
                         "messages.error.invalidNumber",
                         new Replacement("%target%", args[1]));
@@ -72,7 +73,7 @@ public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command
 
         StringBuilder players = new StringBuilder();
         boolean searchInv = command.getName().equals("searchinv");
-        for (Player player : plugin.getServer().getOnlinePlayers()) {
+        for (Player player : Bukkit.getServer().getOnlinePlayers()) {
             Inventory inventory = searchInv ? player.getInventory() : player.getEnderChest();
             int total = 0;
             for (ItemStack itemStack : inventory.getContents()) {
@@ -90,14 +91,14 @@ public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command
         if (!players.isEmpty()) {
             players.delete(players.length() - 2, players.length());
         } else {
-            plugin.sendMessage(
+            lang.sendMessage(
                     sender,
                     "messages.info.player.noMatches",
                     new Replacement("%target%", material.name()));
             return true;
         }
 
-        plugin.sendMessage(
+        lang.sendMessage(
                 sender,
                 "messages.info.player.matches",
                 new Replacement("%target%", material.name()),
diff --git a/plugin/src/main/java/com/lishid/openinv/InternalAccessor.java b/plugin/src/main/java/com/lishid/openinv/util/InternalAccessor.java
similarity index 50%
rename from plugin/src/main/java/com/lishid/openinv/InternalAccessor.java
rename to plugin/src/main/java/com/lishid/openinv/util/InternalAccessor.java
index 63c2a067..55cea7b0 100644
--- a/plugin/src/main/java/com/lishid/openinv/InternalAccessor.java
+++ b/plugin/src/main/java/com/lishid/openinv/util/InternalAccessor.java
@@ -14,76 +14,44 @@
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  */
 
-package com.lishid.openinv;
+package com.lishid.openinv.util;
 
 import com.github.jikoo.planarwrappers.util.version.BukkitVersions;
 import com.github.jikoo.planarwrappers.util.version.Version;
+import com.lishid.openinv.internal.Accessor;
 import com.lishid.openinv.internal.IAnySilentContainer;
-import com.lishid.openinv.internal.IPlayerDataManager;
 import com.lishid.openinv.internal.ISpecialEnderChest;
-import com.lishid.openinv.internal.ISpecialInventory;
 import com.lishid.openinv.internal.ISpecialPlayerInventory;
-import com.lishid.openinv.internal.PlaceholderParser;
-import com.lishid.openinv.util.InventoryAccess;
+import com.lishid.openinv.internal.PlayerManager;
+import com.lishid.openinv.util.lang.LanguageManager;
 import org.bukkit.configuration.ConfigurationSection;
 import org.bukkit.entity.Player;
-import org.bukkit.plugin.Plugin;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
-import java.lang.reflect.Constructor;
-import java.util.logging.Level;
+import java.util.logging.Logger;
 
-class InternalAccessor {
+public class InternalAccessor {
 
-    private final @NotNull Plugin plugin;
-    private final @Nullable String versionPackage;
-    private boolean supported = false;
-    private IPlayerDataManager playerDataManager;
-    private IAnySilentContainer anySilentContainer;
-    private @Nullable PlaceholderParser placeholderParser;
+    private @Nullable Accessor internal;
 
-    InternalAccessor(@NotNull Plugin plugin) {
-        this.plugin = plugin;
-        this.versionPackage = getVersionPackage();
-        checkSupported();
-    }
+    public InternalAccessor(@NotNull Logger logger, @NotNull LanguageManager lang) {
 
-    private void checkSupported() {
-        if (versionPackage == null) {
-            return;
-        }
         try {
-            try {
-                Class.forName("com.lishid.openinv.internal." + this.versionPackage + ".inventory.OpenInventory");
-                this.placeholderParser = createObject(PlaceholderParser.class, "inventory.PlaceholderManager");
-            } catch (ClassNotFoundException e) {
-                Class.forName("com.lishid.openinv.internal." + this.versionPackage + ".SpecialPlayerInventory");
+            if (BukkitVersions.MINECRAFT.equals(Version.of(1, 21))) {
+                internal = new com.lishid.openinv.internal.v1_21_R1.InternalAccessor(logger, lang);
+            } else if (BukkitVersions.MINECRAFT.equals(Version.of(1, 20, 4))) {
+                internal = new com.lishid.openinv.internal.v1_20_R3.InternalAccessor(logger, lang);
+            } else if (BukkitVersions.MINECRAFT.equals(Version.of(1, 20, 6))) {
+                internal = new com.lishid.openinv.internal.v1_20_R4.InternalAccessor(logger, lang);
             }
-            Class.forName("com.lishid.openinv.internal." + this.versionPackage + ".inventory.OpenInventory");
-            Class.forName("com.lishid.openinv.internal." + this.versionPackage + ".SpecialEnderChest");
-            this.playerDataManager = this.createObject(IPlayerDataManager.class, "PlayerDataManager");
-            this.anySilentContainer = this.createObject(IAnySilentContainer.class, "AnySilentContainer");
-            this.supported = InventoryAccess.isUsable();
-        } catch (Exception ignored) {}
-    }
-
-    private @Nullable String getVersionPackage() {
-        if (BukkitVersions.MINECRAFT.lessThan(Version.of(1, 20, 4)) // Min supported version: 1.20.4
-                || BukkitVersions.MINECRAFT.equals(Version.of(1, 20, 5))) { // 1.20.5 not supported at all.
-            return null;
-        }
-        if (BukkitVersions.MINECRAFT.equals(Version.of(1, 20, 4))) { // 1.20.4
-            return "v1_20_R3";
-        }
-        if (BukkitVersions.MINECRAFT.equals(Version.of(1, 20, 6))) { // 1.20.6
-            return "v1_20_R4";
-        }
-        if (BukkitVersions.MINECRAFT.greaterThan(Version.of(1, 21))) {
-            return null;
+            if (internal != null) {
+                InventoryAccess.setProvider(internal::get);
+            }
+        } catch (NoClassDefFoundError | Exception e) {
+            internal = null;
+            InventoryAccess.setProvider(null);
         }
-        // 1.21
-        return "v1_21_R1";
     }
 
     public String getReleasesLink() {
@@ -150,68 +118,9 @@ public String getReleasesLink() {
         if (BukkitVersions.MINECRAFT.lessThanOrEqual(Version.of(1, 20, 3))) { // 1.20.2, 1.20.3
             return "https://github.com/Jikoo/OpenInv/releases/tag/4.4.3";
         }
-        if (BukkitVersions.MINECRAFT.equals(Version.of(1, 20, 5))) { // 1.20.5 shouldn't be used.
-            return "https://github.com/Jikoo/OpenInv/releases";
-        }
         return "https://github.com/Jikoo/OpenInv/releases";
     }
 
-    private @NotNull <T> T createObject(
-            @NotNull Class<? extends T> assignableClass,
-            @NotNull String className,
-            @NotNull Object @NotNull ... params)
-            throws ClassCastException, ReflectiveOperationException {
-        // Fetch internal class if it exists.
-        Class<?> internalClass = Class.forName("com.lishid.openinv.internal." + this.versionPackage + "." + className);
-
-        // Quick return: no parameters, no need to fiddle about finding the correct constructor.
-        if (params.length == 0) {
-            return assignableClass.cast(internalClass.getConstructor().newInstance());
-        }
-
-        // Search constructors for one matching the given parameters
-        nextConstructor: for (Constructor<?> constructor : internalClass.getConstructors()) {
-            Class<?>[] requiredClasses = constructor.getParameterTypes();
-            if (requiredClasses.length != params.length) {
-                continue;
-            }
-            for (int i = 0; i < params.length; ++i) {
-                if (!requiredClasses[i].isAssignableFrom(params[i].getClass())) {
-                    continue nextConstructor;
-                }
-            }
-            return assignableClass.cast(constructor.newInstance(params));
-        }
-
-        StringBuilder builder = new StringBuilder("Found class ").append(internalClass.getName())
-                .append(" but cannot find any matching constructors for [");
-        for (Object object : params) {
-            builder.append(object.getClass().getName()).append(", ");
-        }
-        builder.delete(builder.length() - 2, builder.length());
-
-        String message = builder.append(']').toString();
-        this.plugin.getLogger().warning(message);
-
-        throw new NoSuchMethodException(message);
-    }
-
-    private @NotNull <T extends ISpecialInventory> T createSpecialInventory(
-            @NotNull Class<? extends T> assignableClass,
-            @NotNull String className,
-            @NotNull Object @NotNull ... params) throws InstantiationException {
-        if (!this.supported) {
-            throw new IllegalStateException(String.format("Unsupported server version %s!", BukkitVersions.MINECRAFT));
-        }
-        try {
-            return this.createObject(assignableClass, className, params);
-        } catch (Exception original) {
-            InstantiationException exception = new InstantiationException(String.format("Unable to create a new %s", className));
-            exception.initCause(original.fillInStackTrace());
-            throw exception;
-        }
-    }
-
     /**
      * Creates an instance of the IAnySilentContainer implementation for the current server version.
      *
@@ -219,10 +128,10 @@ public String getReleasesLink() {
      * @throws IllegalStateException if server version is unsupported
      */
     public @NotNull IAnySilentContainer getAnySilentContainer() {
-        if (!this.supported) {
+        if (internal == null) {
             throw new IllegalStateException(String.format("Unsupported server version %s!", BukkitVersions.MINECRAFT));
         }
-        return this.anySilentContainer;
+        return internal.getAnySilentContainer();
     }
 
     /**
@@ -231,28 +140,19 @@ public String getReleasesLink() {
      * @return the IPlayerDataManager
      * @throws IllegalStateException if server version is unsupported
      */
-    public @NotNull IPlayerDataManager getPlayerDataManager() {
-        if (!this.supported) {
+    public @NotNull PlayerManager getPlayerDataManager() {
+        if (internal == null) {
             throw new IllegalStateException(String.format("Unsupported server version %s!", BukkitVersions.MINECRAFT));
         }
-        return this.playerDataManager;
+        return internal.getPlayerManager();
     }
 
     /**
      * Reload internal features.
      */
-    void reload() {
-        if (placeholderParser == null) {
-            return;
-        }
-
-        ConfigurationSection placeholders = plugin.getConfig().getConfigurationSection("placeholders");
-        if (placeholders != null) {
-          try {
-            placeholderParser.load(placeholders);
-          } catch (Exception e) {
-            plugin.getLogger().log(Level.WARNING, "Caught exception loading placeholder overrides!", e);
-          }
+    public void reload(ConfigurationSection config) {
+        if (internal != null) {
+            internal.reload(config);
         }
     }
 
@@ -271,35 +171,33 @@ void reload() {
      * @return true if initialized for a supported server version
      */
     public boolean isSupported() {
-        return this.supported;
+        return internal != null;
     }
 
     /**
-     * Creates an instance of the ISpecialEnderChest implementation for the given Player, or
-     * null if the current version is unsupported.
+     * Creates an instance of the ISpecialEnderChest implementation for the given Player.
      *
      * @param player the Player
-     * @param online true if the Player is online
      * @return the ISpecialEnderChest created
-     * @throws InstantiationException if the ISpecialEnderChest could not be instantiated
      */
-    public ISpecialEnderChest newSpecialEnderChest(final Player player, final boolean online) throws InstantiationException {
-        return this.createSpecialInventory(ISpecialEnderChest.class, "SpecialEnderChest", player, online);
+    public ISpecialEnderChest newSpecialEnderChest(final Player player) {
+        if (internal == null) {
+            throw new IllegalStateException(String.format("Unsupported server version %s!", BukkitVersions.MINECRAFT));
+        }
+        return internal.createEnderChest(player);
     }
 
     /**
-     * Creates an instance of the ISpecialPlayerInventory implementation for the given Player..
+     * Creates an instance of the ISpecialPlayerInventory implementation for the given Player.
      *
      * @param player the Player
      * @return the ISpecialPlayerInventory created
-     * @throws InstantiationException if the ISpecialPlayerInventory could not be instantiated
      */
-    public ISpecialPlayerInventory newSpecialPlayerInventory(final Player player) throws InstantiationException {
-        try {
-            return this.createSpecialInventory(ISpecialPlayerInventory.class, "inventory.OpenInventory", player);
-        }  catch (InstantiationException ignored) {
-            return this.createSpecialInventory(ISpecialPlayerInventory.class, "SpecialPlayerInventory", player, player.isOnline());
+    public ISpecialPlayerInventory newSpecialPlayerInventory(final Player player) {
+        if (internal == null) {
+            throw new IllegalStateException(String.format("Unsupported server version %s!", BukkitVersions.MINECRAFT));
         }
+        return internal.createPlayerInventory(player);
     }
 
 }
diff --git a/api/src/main/java/com/lishid/openinv/util/StringMetric.java b/plugin/src/main/java/com/lishid/openinv/util/StringMetric.java
similarity index 100%
rename from api/src/main/java/com/lishid/openinv/util/StringMetric.java
rename to plugin/src/main/java/com/lishid/openinv/util/StringMetric.java
diff --git a/plugin/src/main/java/com/lishid/openinv/util/TabCompleter.java b/plugin/src/main/java/com/lishid/openinv/util/TabCompleter.java
index 882274fe..f61be773 100644
--- a/plugin/src/main/java/com/lishid/openinv/util/TabCompleter.java
+++ b/plugin/src/main/java/com/lishid/openinv/util/TabCompleter.java
@@ -16,20 +16,21 @@
 
 package com.lishid.openinv.util;
 
+import org.bukkit.Bukkit;
+import org.bukkit.command.CommandSender;
+import org.bukkit.entity.Player;
+import org.bukkit.util.StringUtil;
+
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 import java.util.Locale;
 import java.util.function.Function;
-import org.bukkit.Bukkit;
-import org.bukkit.command.CommandSender;
-import org.bukkit.entity.Player;
-import org.bukkit.util.StringUtil;
 
 /**
  * Utility class for common tab completions.
  */
-public class TabCompleter {
+public final class TabCompleter {
 
     /**
      * Offer tab completions for whole numbers.
@@ -67,7 +68,7 @@ public static List<String> completeEnum(String argument, Class<? extends Enum<?>
         List<String> completions = new ArrayList<>();
 
         for (Enum<?> enumConstant : enumClazz.getEnumConstants()) {
-            String name = enumConstant.name().toLowerCase();
+            String name = enumConstant.name().toLowerCase(Locale.ENGLISH);
             if (name.startsWith(argument)) {
                 completions.add(name);
             }
@@ -133,7 +134,7 @@ public static <T> List<String> completeObject(String argument, Function<T, Strin
         List<String> completions = new ArrayList<>();
 
         for (T option : options) {
-            String optionString = converter.apply(option).toLowerCase();
+            String optionString = converter.apply(option).toLowerCase(Locale.ENGLISH);
             if (optionString.startsWith(argument)) {
                 completions.add(optionString);
             }
@@ -142,6 +143,8 @@ public static <T> List<String> completeObject(String argument, Function<T, Strin
         return completions;
     }
 
-    private TabCompleter() {}
+    private TabCompleter() {
+        throw new IllegalStateException("Cannot create instance of utility class.");
+    }
 
 }
diff --git a/pom.xml b/pom.xml
index 9a94f68a..c4ea08aa 100644
--- a/pom.xml
+++ b/pom.xml
@@ -21,14 +21,16 @@
   <artifactId>openinvparent</artifactId>
   <name>OpenInv</name>
   <url>http://dev.bukkit.org/bukkit-plugins/openinv/</url>
+  <modules>
+    <module>common</module>
+  </modules>
   <version>5.0.0-SNAPSHOT</version>
 
   <packaging>pom</packaging>
 
   <properties>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-    <maven.compiler.source>17</maven.compiler.source>
-    <maven.compiler.target>17</maven.compiler.target>
+    <maven.compiler.system>17</maven.compiler.system>
     <maven.compiler.release>17</maven.compiler.release>
     <!-- Silence IDE warning - property is declared in individual internal modules. -->
     <spigot.version>unknown</spigot.version>
@@ -39,23 +41,21 @@
       <id>all</id>
       <modules>
         <module>api</module>
-        <module>plugin</module>
+        <module>common</module>
         <module>internal/v1_21_R1</module>
         <module>internal/v1_20_R4</module>
         <module>internal/v1_20_R3</module>
-        <module>assembly</module>
+        <module>plugin</module>
       </modules>
     </profile>
 
     <profile>
-      <id>default</id>
+      <id>api-only</id>
       <activation>
         <activeByDefault>true</activeByDefault>
       </activation>
       <modules>
         <module>api</module>
-        <module>plugin</module>
-        <module>assembly</module>
       </modules>
     </profile>
   </profiles>
@@ -89,23 +89,18 @@
         <artifactId>openinvapi</artifactId>
         <groupId>com.lishid</groupId>
         <scope>compile</scope>
-        <version>5.0.0-SNAPSHOT</version>
+        <version>${project.version}</version>
       </dependency>
       <dependency>
-        <artifactId>openinvplugincore</artifactId>
+        <artifactId>openinvcommon</artifactId>
         <groupId>com.lishid</groupId>
         <scope>compile</scope>
-        <version>5.0.0-SNAPSHOT</version>
-        <exclusions>
-          <exclusion>
-            <groupId>com.lishid</groupId>
-            <artifactId>openinvapi</artifactId>
-          </exclusion>
-        </exclusions>
+        <version>${project.version}</version>
       </dependency>
       <dependency>
         <artifactId>planarwrappers</artifactId>
         <groupId>com.github.jikoo</groupId>
+        <scope>compile</scope>
         <version>3.2.3</version>
       </dependency>
     </dependencies>
@@ -126,39 +121,55 @@
 
         <plugin>
           <artifactId>maven-shade-plugin</artifactId>
-          <configuration>
-            <filters>
-              <filter>
-                <!-- Always shade entirety of required modules. -->
-                <artifact>com.lishid:openinv*</artifact>
-                <includes>
-                  <include>**</include>
-                </includes>
-              </filter>
-              <filter>
-                <artifact>*:*</artifact>
-                <!-- Don't warn about file conflicts that'll be clobbered anyway. -->
-                <excludes>
-                  <exclude>META-INF/MANIFEST.MF</exclude>
-                </excludes>
-              </filter>
-            </filters>
-            <minimizeJar>true</minimizeJar>
-          </configuration>
-          <executions>
-            <execution>
-              <phase>package</phase>
-              <goals>
-                <goal>shade</goal>
-              </goals>
-            </execution>
-          </executions>
           <groupId>org.apache.maven.plugins</groupId>
           <version>3.6.0</version>
         </plugin>
 
+        <plugin>
+          <artifactId>maven-resources-plugin</artifactId>
+          <groupId>org.apache.maven.plugins</groupId>
+          <version>3.3.1</version>
+        </plugin>
+
+        <plugin>
+          <artifactId>maven-jar-plugin</artifactId>
+          <groupId>org.apache.maven.plugins</groupId>
+          <version>3.4.1</version>
+          <configuration>
+            <archive>
+              <manifestEntries>
+                <paperweight-mappings-namespace>spigot</paperweight-mappings-namespace>
+              </manifestEntries>
+            </archive>
+          </configuration>
+        </plugin>
+
         <plugin>
           <artifactId>maven-compiler-plugin</artifactId>
+          <configuration>
+            <annotationProcessorPaths>
+              <path>
+                <groupId>com.google.errorprone</groupId>
+                <artifactId>error_prone_core</artifactId>
+                <version>2.28.0</version>
+              </path>
+            </annotationProcessorPaths>
+            <compilerArgs>
+              <arg>-XDcompilePolicy=simple</arg>
+              <arg>-Xplugin:ErrorProne</arg>
+              <arg>-J--add-exports=jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED</arg>
+              <arg>-J--add-exports=jdk.compiler/com.sun.tools.javac.file=ALL-UNNAMED</arg>
+              <arg>-J--add-exports=jdk.compiler/com.sun.tools.javac.main=ALL-UNNAMED</arg>
+              <arg>-J--add-exports=jdk.compiler/com.sun.tools.javac.model=ALL-UNNAMED</arg>
+              <arg>-J--add-exports=jdk.compiler/com.sun.tools.javac.parser=ALL-UNNAMED</arg>
+              <arg>-J--add-exports=jdk.compiler/com.sun.tools.javac.processing=ALL-UNNAMED</arg>
+              <arg>-J--add-exports=jdk.compiler/com.sun.tools.javac.tree=ALL-UNNAMED</arg>
+              <arg>-J--add-exports=jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED</arg>
+              <arg>-J--add-opens=jdk.compiler/com.sun.tools.javac.code=ALL-UNNAMED</arg>
+              <arg>-J--add-opens=jdk.compiler/com.sun.tools.javac.comp=ALL-UNNAMED</arg>
+            </compilerArgs>
+            <fork>true</fork>
+          </configuration>
           <groupId>org.apache.maven.plugins</groupId>
           <version>3.13.0</version>
         </plugin>
@@ -170,9 +181,7 @@
         </plugin>
 
         <plugin>
-          <groupId>net.md-5</groupId>
           <artifactId>specialsource-maven-plugin</artifactId>
-          <version>2.0.3</version>
           <executions>
             <execution>
               <phase>package</phase>
@@ -201,6 +210,8 @@
               </configuration>
             </execution>
           </executions>
+          <groupId>net.md-5</groupId>
+          <version>2.0.3</version>
         </plugin>
       </plugins>
     </pluginManagement>