diff --git a/build.gradle b/build.gradle
index 96c867941..7ec7a787a 100644
--- a/build.gradle
+++ b/build.gradle
@@ -108,6 +108,8 @@ dependencies {
 
     // https://mvnrepository.com/artifact/it.unimi.dsi/fastutil
     api 'it.unimi.dsi:fastutil:8.5.6'
+    implementation group: 'space.vectrix.flare', name: 'flare', version: '2.0.0'
+    implementation group: 'space.vectrix.flare', name: 'flare-fastutil', version: '2.0.0'
 
     // https://mvnrepository.com/artifact/com.google.code.gson/gson
     api 'com.google.code.gson:gson:2.8.9'
diff --git a/src/main/java/net/minestom/server/entity/Entity.java b/src/main/java/net/minestom/server/entity/Entity.java
index b039a3e33..15ba9f511 100644
--- a/src/main/java/net/minestom/server/entity/Entity.java
+++ b/src/main/java/net/minestom/server/entity/Entity.java
@@ -53,6 +53,7 @@ import org.jetbrains.annotations.ApiStatus;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.jglrxavpok.hephaistos.nbt.mutable.MutableNBTCompound;
+import space.vectrix.flare.fastutil.Int2ObjectSyncMap;
 
 import java.time.Duration;
 import java.time.temporal.TemporalUnit;
@@ -73,7 +74,7 @@ import java.util.function.UnaryOperator;
  */
 public class Entity implements Viewable, Tickable, Schedulable, TagHandler, PermissionHandler, HoverEventSource<ShowEntity>, Sound.Emitter {
 
-    private static final Map<Integer, Entity> ENTITY_BY_ID = new ConcurrentHashMap<>();
+    private static final Int2ObjectSyncMap<Entity> ENTITY_BY_ID = Int2ObjectSyncMap.hashmap();
     private static final Map<UUID, Entity> ENTITY_BY_UUID = new ConcurrentHashMap<>();
     private static final AtomicInteger LAST_ENTITY_ID = new AtomicInteger();
 
@@ -217,7 +218,7 @@ public class Entity implements Viewable, Tickable, Schedulable, TagHandler, Perm
      * @return the entity having the specified id, null if not found
      */
     public static @Nullable Entity getEntity(int id) {
-        return Entity.ENTITY_BY_ID.getOrDefault(id, null);
+        return Entity.ENTITY_BY_ID.get(id);
     }
 
     /**
diff --git a/src/main/java/net/minestom/server/instance/InstanceContainer.java b/src/main/java/net/minestom/server/instance/InstanceContainer.java
index 3ca632c8e..f323dedc0 100644
--- a/src/main/java/net/minestom/server/instance/InstanceContainer.java
+++ b/src/main/java/net/minestom/server/instance/InstanceContainer.java
@@ -28,6 +28,7 @@ import net.minestom.server.world.DimensionType;
 import org.jetbrains.annotations.ApiStatus;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
+import space.vectrix.flare.fastutil.Long2ObjectSyncMap;
 
 import java.util.*;
 import java.util.concurrent.CompletableFuture;
@@ -48,7 +49,7 @@ public class InstanceContainer extends Instance {
     private ChunkGenerator chunkGenerator;
     // (chunk index -> chunk) map, contains all the chunks in the instance
     // used as a monitor when access is required
-    private final Long2ObjectMap<Chunk> chunks = new Long2ObjectOpenHashMap<>();
+    private final Long2ObjectSyncMap<Chunk> chunks = Long2ObjectSyncMap.hashmap();
     private final Long2ObjectMap<CompletableFuture<Chunk>> loadingChunks = new Long2ObjectOpenHashMap<>();
 
     private final Lock changingBlockLock = new ReentrantLock();
@@ -220,9 +221,7 @@ public class InstanceContainer extends Instance {
         // Remove all entities in chunk
         getEntityTracker().chunkEntities(chunkX, chunkZ, EntityTracker.Target.ENTITIES, Entity::remove);
         // Clear cache
-        synchronized (chunks) {
-            this.chunks.remove(index);
-        }
+        this.chunks.remove(index);
         chunk.unload();
         UPDATE_MANAGER.signalChunkUnload(chunk);
     }
@@ -230,9 +229,7 @@ public class InstanceContainer extends Instance {
     @Override
     public Chunk getChunk(int chunkX, int chunkZ) {
         final long index = ChunkUtils.getChunkIndex(chunkX, chunkZ);
-        synchronized (chunks) {
-            return chunks.get(index);
-        }
+        return chunks.get(index);
     }
 
     @Override
@@ -379,13 +376,11 @@ public class InstanceContainer extends Instance {
         InstanceContainer copiedInstance = new InstanceContainer(UUID.randomUUID(), getDimensionType());
         copiedInstance.srcInstance = this;
         copiedInstance.lastBlockChangeTime = lastBlockChangeTime;
-        synchronized (chunks) {
-            for (Chunk chunk : chunks.values()) {
-                final int chunkX = chunk.getChunkX();
-                final int chunkZ = chunk.getChunkZ();
-                final Chunk copiedChunk = chunk.copy(copiedInstance, chunkX, chunkZ);
-                copiedInstance.cacheChunk(copiedChunk);
-            }
+        for (Chunk chunk : chunks.values()) {
+            final int chunkX = chunk.getChunkX();
+            final int chunkZ = chunk.getChunkZ();
+            final Chunk copiedChunk = chunk.copy(copiedInstance, chunkX, chunkZ);
+            copiedInstance.cacheChunk(copiedChunk);
         }
         return copiedInstance;
     }
@@ -437,9 +432,7 @@ public class InstanceContainer extends Instance {
      */
     @Override
     public @NotNull Collection<@NotNull Chunk> getChunks() {
-        synchronized (chunks) {
-            return List.copyOf(chunks.values());
-        }
+        return chunks.values();
     }
 
     /**
@@ -529,9 +522,7 @@ public class InstanceContainer extends Instance {
 
     private void cacheChunk(@NotNull Chunk chunk) {
         final long index = ChunkUtils.getChunkIndex(chunk);
-        synchronized (chunks) {
-            this.chunks.put(index, chunk);
-        }
+        this.chunks.put(index, chunk);
         UPDATE_MANAGER.signalChunkLoad(chunk);
     }
 }
\ No newline at end of file