diff --git a/src/main/java/de/bixilon/minosoft/data/DefaultEntityFactories.kt b/src/main/java/de/bixilon/minosoft/data/DefaultEntityFactories.kt
index af29842ac..b93875ff3 100644
--- a/src/main/java/de/bixilon/minosoft/data/DefaultEntityFactories.kt
+++ b/src/main/java/de/bixilon/minosoft/data/DefaultEntityFactories.kt
@@ -190,7 +190,7 @@ object DefaultEntityFactories {
 
         val tweakedFactory = ENTITY_FACTORY_MAP[tweakedResourceLocation] ?: throw UnknownEntityException("Can not find tweaked entity type: $tweakedResourceLocation for $factory")
 
-        val tweakedEntityType = connection.mapping.entityRegistry[tweakedResourceLocation] ?: throw UnknownEntityException("Can not find tweaked entity type data in ${connection.version}: $tweakedResourceLocation for $factory")
+        val tweakedEntityType = connection.mapping.entityTypeRegistry[tweakedResourceLocation] ?: throw UnknownEntityException("Can not find tweaked entity type data in ${connection.version}: $tweakedResourceLocation for $factory")
         return tweakedFactory.build(connection, tweakedEntityType, position, rotation)
     }
 
diff --git a/src/main/java/de/bixilon/minosoft/data/Tag.kt b/src/main/java/de/bixilon/minosoft/data/Tag.kt
index 1ae3c8ed4..bb0eca4ed 100644
--- a/src/main/java/de/bixilon/minosoft/data/Tag.kt
+++ b/src/main/java/de/bixilon/minosoft/data/Tag.kt
@@ -14,7 +14,7 @@ package de.bixilon.minosoft.data
 
 import de.bixilon.minosoft.data.mappings.ResourceLocation
 
-data class Tag(
+data class Tag<T>(
     val resourceLocation: ResourceLocation,
-    val ids: IntArray,
+    val ids: Set<T>,
 )
diff --git a/src/main/java/de/bixilon/minosoft/data/mappings/registry/Registry.kt b/src/main/java/de/bixilon/minosoft/data/mappings/registry/Registry.kt
index 62584ed90..a8c44daff 100644
--- a/src/main/java/de/bixilon/minosoft/data/mappings/registry/Registry.kt
+++ b/src/main/java/de/bixilon/minosoft/data/mappings/registry/Registry.kt
@@ -37,7 +37,7 @@ open class Registry<T : RegistryItem>(
     }
 
     open operator fun get(id: Int): T {
-        return idValueMap[id] ?: parentRegistry?.get(id)!!
+        return idValueMap[id] ?: parentRegistry?.get(id) ?: throw NullPointerException("Can not find item with id $id")
     }
 
     open fun getId(value: T): Int {
diff --git a/src/main/java/de/bixilon/minosoft/data/mappings/versions/VersionMapping.kt b/src/main/java/de/bixilon/minosoft/data/mappings/versions/VersionMapping.kt
index 532a92489..c40135e65 100644
--- a/src/main/java/de/bixilon/minosoft/data/mappings/versions/VersionMapping.kt
+++ b/src/main/java/de/bixilon/minosoft/data/mappings/versions/VersionMapping.kt
@@ -91,7 +91,7 @@ class VersionMapping {
     val blockStateIdMap: MutableMap<Int, BlockState> = mutableMapOf()
 
     val entityMetaIndexMap: MutableMap<EntityMetaDataFields, Int> = mutableMapOf()
-    val entityRegistry: Registry<EntityType> = Registry()
+    val entityTypeRegistry: Registry<EntityType> = Registry()
 
     val blockEntityTypeRegistry = BlockEntityTypeRegistry()
     val blockEntityMetaDataTypeRegistry: Registry<BlockEntityMetaType> = Registry()
@@ -190,7 +190,7 @@ class VersionMapping {
 
         villagerProfessionRegistry.initialize(pixlyzerData["villager_professions"]?.asJsonObject, this, VillagerProfession)
 
-        entityRegistry.initialize(pixlyzerData["entities"]?.asJsonObject, this, EntityType)
+        entityTypeRegistry.initialize(pixlyzerData["entities"]?.asJsonObject, this, EntityType)
 
         blockEntityMetaDataTypeRegistry.initialize(pixlyzerData["block_entity_meta_data_types"]?.asJsonObject, this, BlockEntityMetaType, alternative = DefaultRegistries.BLOCK_ENTITY_META_TYPE_REGISTRY.forVersion(version))
 
diff --git a/src/main/java/de/bixilon/minosoft/data/player/Player.kt b/src/main/java/de/bixilon/minosoft/data/player/Player.kt
index c0f87c0d0..71ffd575c 100644
--- a/src/main/java/de/bixilon/minosoft/data/player/Player.kt
+++ b/src/main/java/de/bixilon/minosoft/data/player/Player.kt
@@ -30,7 +30,7 @@ class Player(
     val healthCondition = PlayerHealthCondition()
     val experienceCondition = PlayerExperienceCondition()
     var spawnPosition: Vec3i = VecUtil.EMPTY_VEC3I
-    val entity: PlayerEntity = PlayerEntity(connection, connection.mapping.entityRegistry[PlayerEntity.RESOURCE_LOCATION]!!, VecUtil.EMPTY_VEC3, EntityRotation(0.0, 0.0), account.username)
+    val entity: PlayerEntity = PlayerEntity(connection, connection.mapping.entityTypeRegistry[PlayerEntity.RESOURCE_LOCATION]!!, VecUtil.EMPTY_VEC3, EntityRotation(0.0, 0.0), account.username)
 
     @Deprecated(message = "Will be replaced with some kind of teleport manager, ...")
     var isSpawnConfirmed = false
diff --git a/src/main/java/de/bixilon/minosoft/protocol/packets/s2c/play/EntityObjectSpawnS2CP.kt b/src/main/java/de/bixilon/minosoft/protocol/packets/s2c/play/EntityObjectSpawnS2CP.kt
index 1db09b897..aa178c500 100644
--- a/src/main/java/de/bixilon/minosoft/protocol/packets/s2c/play/EntityObjectSpawnS2CP.kt
+++ b/src/main/java/de/bixilon/minosoft/protocol/packets/s2c/play/EntityObjectSpawnS2CP.kt
@@ -61,9 +61,9 @@ class EntityObjectSpawnS2CP(buffer: PlayInByteBuffer) : PlayS2CPacket() {
         }
         entity = if (buffer.versionId < ProtocolVersions.V_19W05A) {
             val entityResourceLocation = ENTITY_OBJECT_REGISTRY[type].resourceLocation
-            buffer.connection.mapping.entityRegistry[entityResourceLocation]!!.build(buffer.connection, position, rotation, null, buffer.versionId)!! // ToDo: Entity meta data tweaking
+            buffer.connection.mapping.entityTypeRegistry[entityResourceLocation]!!.build(buffer.connection, position, rotation, null, buffer.versionId)!! // ToDo: Entity meta data tweaking
         } else {
-            buffer.connection.mapping.entityRegistry[type].build(buffer.connection, position, rotation, null, buffer.versionId)!!
+            buffer.connection.mapping.entityTypeRegistry[type].build(buffer.connection, position, rotation, null, buffer.versionId)!!
         }
     }
 
diff --git a/src/main/java/de/bixilon/minosoft/protocol/packets/s2c/play/ExperienceOrbSpawnS2CP.kt b/src/main/java/de/bixilon/minosoft/protocol/packets/s2c/play/ExperienceOrbSpawnS2CP.kt
index 489810819..b227ac1a5 100644
--- a/src/main/java/de/bixilon/minosoft/protocol/packets/s2c/play/ExperienceOrbSpawnS2CP.kt
+++ b/src/main/java/de/bixilon/minosoft/protocol/packets/s2c/play/ExperienceOrbSpawnS2CP.kt
@@ -27,7 +27,7 @@ class ExperienceOrbSpawnS2CP(buffer: PlayInByteBuffer) : PlayS2CPacket() {
     val entityId: Int = buffer.readEntityId()
     val entity: ExperienceOrb = ExperienceOrb(
         connection = buffer.connection,
-        entityType = buffer.connection.mapping.entityRegistry[ExperienceOrb.RESOURCE_LOCATION]!!,
+        entityType = buffer.connection.mapping.entityTypeRegistry[ExperienceOrb.RESOURCE_LOCATION]!!,
         position = if (buffer.versionId < ProtocolVersions.V_16W06A) {
             Vec3(buffer.readFixedPointNumberInt(), buffer.readFixedPointNumberInt(), buffer.readFixedPointNumberInt())
         } else {
diff --git a/src/main/java/de/bixilon/minosoft/protocol/packets/s2c/play/GlobalEntitySpawnS2CP.kt b/src/main/java/de/bixilon/minosoft/protocol/packets/s2c/play/GlobalEntitySpawnS2CP.kt
index e2189370e..098ce92fa 100644
--- a/src/main/java/de/bixilon/minosoft/protocol/packets/s2c/play/GlobalEntitySpawnS2CP.kt
+++ b/src/main/java/de/bixilon/minosoft/protocol/packets/s2c/play/GlobalEntitySpawnS2CP.kt
@@ -35,7 +35,7 @@ class GlobalEntitySpawnS2CP(buffer: PlayInByteBuffer) : PlayS2CPacket() {
             buffer.readPosition()
         }
 
-        entity = LightningBolt(buffer.connection, buffer.connection.mapping.entityRegistry[LightningBolt.RESOURCE_LOCATION]!!, position)
+        entity = LightningBolt(buffer.connection, buffer.connection.mapping.entityTypeRegistry[LightningBolt.RESOURCE_LOCATION]!!, position)
     }
 
     override fun handle(connection: PlayConnection) {
diff --git a/src/main/java/de/bixilon/minosoft/protocol/packets/s2c/play/MobSpawnS2CP.kt b/src/main/java/de/bixilon/minosoft/protocol/packets/s2c/play/MobSpawnS2CP.kt
index 4ba635e29..072e12443 100644
--- a/src/main/java/de/bixilon/minosoft/protocol/packets/s2c/play/MobSpawnS2CP.kt
+++ b/src/main/java/de/bixilon/minosoft/protocol/packets/s2c/play/MobSpawnS2CP.kt
@@ -55,7 +55,7 @@ class MobSpawnS2CP(buffer: PlayInByteBuffer) : PlayS2CPacket() {
         } else {
             null
         }
-        val entityType = buffer.connection.mapping.entityRegistry[typeId]
+        val entityType = buffer.connection.mapping.entityTypeRegistry[typeId]
         entity = entityType.build(buffer.connection, position, rotation, metaData, buffer.versionId)!!
         entity.velocity = velocity
         metaData?.let {
diff --git a/src/main/java/de/bixilon/minosoft/protocol/packets/s2c/play/PaintingSpawnS2CP.kt b/src/main/java/de/bixilon/minosoft/protocol/packets/s2c/play/PaintingSpawnS2CP.kt
index 1e127fb72..145788ba8 100644
--- a/src/main/java/de/bixilon/minosoft/protocol/packets/s2c/play/PaintingSpawnS2CP.kt
+++ b/src/main/java/de/bixilon/minosoft/protocol/packets/s2c/play/PaintingSpawnS2CP.kt
@@ -52,7 +52,7 @@ class PaintingSpawnS2CP(buffer: PlayInByteBuffer) : PlayS2CPacket() {
             position = buffer.readBlockPosition()
             direction = byId(buffer.readUnsignedByte())
         }
-        entity = Painting(buffer.connection, buffer.connection.mapping.entityRegistry[Painting.RESOURCE_LOCATION]!!, position, direction, motive!!)
+        entity = Painting(buffer.connection, buffer.connection.mapping.entityTypeRegistry[Painting.RESOURCE_LOCATION]!!, position, direction, motive!!)
     }
 
     override fun handle(connection: PlayConnection) {
diff --git a/src/main/java/de/bixilon/minosoft/protocol/packets/s2c/play/PlayerEntitySpawnS2CP.kt b/src/main/java/de/bixilon/minosoft/protocol/packets/s2c/play/PlayerEntitySpawnS2CP.kt
index 3e1edffc7..5ce5ba72a 100644
--- a/src/main/java/de/bixilon/minosoft/protocol/packets/s2c/play/PlayerEntitySpawnS2CP.kt
+++ b/src/main/java/de/bixilon/minosoft/protocol/packets/s2c/play/PlayerEntitySpawnS2CP.kt
@@ -68,7 +68,7 @@ class PlayerEntitySpawnS2CP(buffer: PlayInByteBuffer) : PlayS2CPacket() {
         }
         entity = PlayerEntity(
             connection = buffer.connection,
-            entityType = buffer.connection.mapping.entityRegistry[PlayerEntity.RESOURCE_LOCATION]!!,
+            entityType = buffer.connection.mapping.entityTypeRegistry[PlayerEntity.RESOURCE_LOCATION]!!,
             position = position,
             rotation = EntityRotation(yaw.toFloat(), pitch.toFloat(), 0.0f),
             name = name,
diff --git a/src/main/java/de/bixilon/minosoft/protocol/packets/s2c/play/TagsS2CP.kt b/src/main/java/de/bixilon/minosoft/protocol/packets/s2c/play/TagsS2CP.kt
index 2f659762c..330d37e27 100644
--- a/src/main/java/de/bixilon/minosoft/protocol/packets/s2c/play/TagsS2CP.kt
+++ b/src/main/java/de/bixilon/minosoft/protocol/packets/s2c/play/TagsS2CP.kt
@@ -23,23 +23,29 @@ import de.bixilon.minosoft.util.logging.LogLevels
 import de.bixilon.minosoft.util.logging.LogMessageType
 
 class TagsS2CP(buffer: PlayInByteBuffer) : PlayS2CPacket() {
-    val tags: Map<ResourceLocation, List<Tag>>
+    val tags: Map<ResourceLocation, List<Tag<Any>>>
 
     init {
-        val tags: MutableMap<ResourceLocation, List<Tag>> = mutableMapOf()
+        val tags: MutableMap<ResourceLocation, List<Tag<Any>>> = mutableMapOf()
         if (buffer.versionId < ProtocolVersions.V_20W51A) {
-            tags[BLOCK_TAG_RESOURCE_LOCATION] = buffer.readTagArray().toList()
-            tags[ITEM_TAG_RESOURCE_LOCATION] = buffer.readTagArray().toList()
-            tags[FLUID_TAG_RESOURCE_LOCATION] = buffer.readTagArray().toList() // ToDo: when was this added? Was not available in 18w01
+            tags[BLOCK_TAG_RESOURCE_LOCATION] = buffer.readTagArray { buffer.connection.mapping.getBlockState(it)!! }
+            tags[ITEM_TAG_RESOURCE_LOCATION] = buffer.readTagArray { buffer.connection.mapping.itemRegistry[it] }
+            tags[FLUID_TAG_RESOURCE_LOCATION] = buffer.readTagArray { buffer.connection.mapping.fluidRegistry[it] } // ToDo: when was this added? Was not available in 18w01
             if (buffer.versionId >= ProtocolVersions.V_18W43A) {
-                tags[ENTITY_TYPE_TAG_RESOURCE_LOCATION] = buffer.readTagArray().toList()
+                tags[ENTITY_TYPE_TAG_RESOURCE_LOCATION] = buffer.readTagArray { buffer.connection.mapping.entityTypeRegistry[it] }
             }
             if (buffer.versionId >= ProtocolVersions.V_20W49A) {
-                tags[GAME_EVENT_TAG_RESOURCE_LOCATION] = buffer.readTagArray().toList()
+                tags[GAME_EVENT_TAG_RESOURCE_LOCATION] = buffer.readTagArray { it }
             }
         } else {
             for (i in 0 until buffer.readVarInt()) {
-                tags[buffer.readResourceLocation()] = buffer.readTagArray().toList()
+                when (buffer.readResourceLocation()) {
+                    BLOCK_TAG_RESOURCE_LOCATION -> buffer.readTagArray { buffer.connection.mapping.blockRegistry[it] }
+                    ITEM_TAG_RESOURCE_LOCATION -> buffer.readTagArray { buffer.connection.mapping.itemRegistry[it] }
+                    FLUID_TAG_RESOURCE_LOCATION -> buffer.readTagArray { buffer.connection.mapping.fluidRegistry[it] }
+                    ENTITY_TYPE_TAG_RESOURCE_LOCATION -> buffer.readTagArray { buffer.connection.mapping.entityTypeRegistry[it] }
+                    GAME_EVENT_TAG_RESOURCE_LOCATION -> buffer.readTagArray { it }
+                }
             }
         }
         this.tags = tags.toMap()
diff --git a/src/main/java/de/bixilon/minosoft/protocol/protocol/InByteBuffer.kt b/src/main/java/de/bixilon/minosoft/protocol/protocol/InByteBuffer.kt
index c0f66c45d..5b200b693 100644
--- a/src/main/java/de/bixilon/minosoft/protocol/protocol/InByteBuffer.kt
+++ b/src/main/java/de/bixilon/minosoft/protocol/protocol/InByteBuffer.kt
@@ -409,12 +409,18 @@ open class InByteBuffer {
         return String(Base64.getEncoder().encode(readRest()))
     }
 
-    fun readTag(): Tag {
-        return Tag(readResourceLocation(), readVarIntArray())
+    fun <T> readTag(idResolver: (Int) -> T): Tag<T> {
+        val resourceLocation = readResourceLocation()
+        val ids = readVarIntArray()
+        val items: MutableSet<T> = mutableSetOf()
+        for (id in ids) {
+            items += idResolver(id)
+        }
+        return Tag(resourceLocation, items.toSet())
     }
 
-    fun readTagArray(length: Int = readVarInt()): Array<Tag> {
-        return readArray(length) { readTag() }
+    fun <T> readTagArray(length: Int = readVarInt(), idResolver: (Int) -> T): List<Tag<T>> {
+        return (readArray(length) { readTag(idResolver) }).toList()
     }
 
     fun <T> readOptional(reader: () -> T): T? {