diff --git a/src/data/kotlin/ru/dbotthepony/mc/otm/datagen/tags/Tags.kt b/src/data/kotlin/ru/dbotthepony/mc/otm/datagen/tags/Tags.kt
index 096f58816..71cd971b5 100644
--- a/src/data/kotlin/ru/dbotthepony/mc/otm/datagen/tags/Tags.kt
+++ b/src/data/kotlin/ru/dbotthepony/mc/otm/datagen/tags/Tags.kt
@@ -47,10 +47,10 @@ fun addTags(tagsProvider: TagsProvider) {
 		MBlocks.STORAGE_CABLE
 	)
 
-	tagsProvider.items.appender(MItemTags.CRAFTING_TABLES).add(Items.CRAFTING_TABLE)
-	tagsProvider.blocks.appender(MBlockTags.CRAFTING_TABLES).add(Blocks.CRAFTING_TABLE)
+	tagsProvider.items.Appender(MItemTags.CRAFTING_TABLES).add(Items.CRAFTING_TABLE)
+	tagsProvider.blocks.Appender(MBlockTags.CRAFTING_TABLES).add(Blocks.CRAFTING_TABLE)
 
-	tagsProvider.items.appender(MItemTags.MINECART_CARGO_CRATES).add(MItems.CARGO_CRATE_MINECARTS.values)
+	tagsProvider.items.Appender(MItemTags.MINECART_CARGO_CRATES).add(MItems.CARGO_CRATE_MINECARTS.values)
 
 	tagsProvider.items.forge("hardened_glass").add(MRegistry.INDUSTRIAL_GLASS.allItems.values)
 	tagsProvider.items.forge("hardened_glass/colorless").add(MRegistry.INDUSTRIAL_GLASS.item)
@@ -74,25 +74,25 @@ fun addTags(tagsProvider: TagsProvider) {
 	MRegistry.INDUSTRIAL_GLASS.forEachBlock { s, _, block -> tagsProvider.blocks.forge("hardened_glass/$s").add(block) }
 	MRegistry.INDUSTRIAL_GLASS_PANE.forEachBlock { s, _, block -> tagsProvider.blocks.forge("hardened_glass_panes/$s").add(block) }
 
-	tagsProvider.items.appender(MItemTags.INDUSTRIAL_GLASS).add(MRegistry.INDUSTRIAL_GLASS.allItems.values)
-	tagsProvider.blocks.appender(MBlockTags.INDUSTRIAL_GLASS).add(MRegistry.INDUSTRIAL_GLASS.allBlocks.values)
-	tagsProvider.blocks.appender(MBlockTags.CARGO_CRATES).add(MRegistry.CARGO_CRATES.allBlocks.values)
+	tagsProvider.items.Appender(MItemTags.INDUSTRIAL_GLASS).add(MRegistry.INDUSTRIAL_GLASS.allItems.values)
+	tagsProvider.blocks.Appender(MBlockTags.INDUSTRIAL_GLASS).add(MRegistry.INDUSTRIAL_GLASS.allBlocks.values)
+	tagsProvider.blocks.Appender(MBlockTags.CARGO_CRATES).add(MRegistry.CARGO_CRATES.allBlocks.values)
 
-	tagsProvider.items.appender(ItemTags.DOORS).add(MItems.TRITANIUM_DOOR.values)
-	tagsProvider.blocks.appender(BlockTags.DOORS).add(MBlocks.TRITANIUM_DOOR.values)
+	tagsProvider.items.Appender(ItemTags.DOORS).add(MItems.TRITANIUM_DOOR.values)
+	tagsProvider.blocks.Appender(BlockTags.DOORS).add(MBlocks.TRITANIUM_DOOR.values)
 
-	tagsProvider.items.appender(ItemTags.TRAPDOORS).add(MItems.TRITANIUM_TRAPDOOR.values)
-	tagsProvider.blocks.appender(BlockTags.TRAPDOORS).add(MBlocks.TRITANIUM_TRAPDOOR.values)
+	tagsProvider.items.Appender(ItemTags.TRAPDOORS).add(MItems.TRITANIUM_TRAPDOOR.values)
+	tagsProvider.blocks.Appender(BlockTags.TRAPDOORS).add(MBlocks.TRITANIUM_TRAPDOOR.values)
 
-	tagsProvider.blocks.appender(BlockTags.PRESSURE_PLATES).add(MRegistry.TRITANIUM_PRESSURE_PLATE.allBlocks.values)
+	tagsProvider.blocks.Appender(BlockTags.PRESSURE_PLATES).add(MRegistry.TRITANIUM_PRESSURE_PLATE.allBlocks.values)
 
-	tagsProvider.items.appender(MItemTags.MACHINES).add(MItems.MACHINES)
-	tagsProvider.blocks.appender(MBlockTags.MACHINES).add(MItems.MACHINES.stream().map { it!!.block })
+	tagsProvider.items.Appender(MItemTags.MACHINES).add(MItems.MACHINES)
+	tagsProvider.blocks.Appender(MBlockTags.MACHINES).add(MItems.MACHINES.stream().map { it!!.block })
 
-	tagsProvider.blocks.appender(BlockTags.ANVIL).add(MBlocks.TRITANIUM_ANVIL)
+	tagsProvider.blocks.Appender(BlockTags.ANVIL).add(MBlocks.TRITANIUM_ANVIL)
 
-	tagsProvider.items.appender(MItemTags.TRITANIUM_NUGGETS).add(MItems.TRITANIUM_NUGGET)
-	tagsProvider.items.appender(MItemTags.NUGGETS).add(MItems.TRITANIUM_NUGGET)
+	tagsProvider.items.Appender(MItemTags.TRITANIUM_NUGGETS).add(MItems.TRITANIUM_NUGGET)
+	tagsProvider.items.Appender(MItemTags.NUGGETS).add(MItems.TRITANIUM_NUGGET)
 
 	tagsProvider.items.forge("armors")
 		.add("helmets", MItems.TRITANIUM_HELMET)
@@ -113,30 +113,30 @@ fun addTags(tagsProvider: TagsProvider) {
 		.add("shields", MItems.TRITANIUM_SHIELD)
 	tagsProvider.items.forge("shears").add(MItems.TRITANIUM_SHEARS)
 
-	tagsProvider.blocks.appender(BlockTags.STAIRS)
+	tagsProvider.blocks.Appender(BlockTags.STAIRS)
 		.add(MRegistry.FLOOR_TILES_STAIRS.blocks.values)
 		.add(MRegistry.TRITANIUM_STAIRS.allBlocks.values)
 		.add(MRegistry.TRITANIUM_STRIPED_STAIRS.flatBlocks)
 		.add(MBlocks.TRITANIUM_STRIPED_STAIRS)
 
-	tagsProvider.blocks.appender(BlockTags.SLABS)
+	tagsProvider.blocks.Appender(BlockTags.SLABS)
 		.add(MRegistry.TRITANIUM_SLAB.allBlocks.values)
 		.add(MRegistry.TRITANIUM_STRIPED_SLAB.flatBlocks)
 		.add(MRegistry.FLOOR_TILES_SLAB.blocks.values)
 		.add(MBlocks.TRITANIUM_STRIPED_SLAB)
 
-	tagsProvider.blocks.appender(BlockTags.WALLS)
+	tagsProvider.blocks.Appender(BlockTags.WALLS)
 		.add(MRegistry.TRITANIUM_WALL.allBlocks.values)
 		.add(MRegistry.TRITANIUM_STRIPED_WALL.flatBlocks)
 		.add(MBlocks.TRITANIUM_STRIPED_WALL)
 
-	tagsProvider.items.appender(ItemTags.SLABS)
+	tagsProvider.items.Appender(ItemTags.SLABS)
 		.add(MRegistry.TRITANIUM_SLAB.allItems.values)
 		.add(MRegistry.TRITANIUM_STRIPED_SLAB.flatItems)
 		.add(MRegistry.FLOOR_TILES_SLAB.items.values)
 		.add(MItems.TRITANIUM_STRIPED_SLAB)
 
-	tagsProvider.items.appender(ItemTags.WALLS)
+	tagsProvider.items.Appender(ItemTags.WALLS)
 		.add(MRegistry.TRITANIUM_WALL.allItems.values)
 		.add(MRegistry.TRITANIUM_STRIPED_WALL.flatItems)
 		.add(MItems.TRITANIUM_STRIPED_WALL)
diff --git a/src/data/kotlin/ru/dbotthepony/mc/otm/datagen/tags/TagsProvider.kt b/src/data/kotlin/ru/dbotthepony/mc/otm/datagen/tags/TagsProvider.kt
index 67bbdcb67..370522b10 100644
--- a/src/data/kotlin/ru/dbotthepony/mc/otm/datagen/tags/TagsProvider.kt
+++ b/src/data/kotlin/ru/dbotthepony/mc/otm/datagen/tags/TagsProvider.kt
@@ -22,62 +22,110 @@ import ru.dbotthepony.mc.otm.datagen.DataGen
 import java.util.stream.Stream
 import net.minecraft.data.tags.TagsProvider as MinecraftTagsProvider
 
-interface MTagAppender<T> {
-	fun add(value: T): MTagAppender<T>
-	fun addSafe(value: T): Boolean
-	fun add(vararg values: T): MTagAppender<T>
-	fun addSafe(vararg values: T): Boolean {
-		var any = false
-		for (value in values) any = addSafe(value)
-		return any
-	}
-
-	fun add(values: Collection<T>): MTagAppender<T>
-	fun add(values: Stream<out T>): MTagAppender<T> = add(values.toList())
-
-	fun addSafe(values: Collection<T>): Boolean {
-		var any = false
-		for (value in values) any = addSafe(value)
-		return any
-	}
-}
-
-interface ForgeTagAppender<T> : MTagAppender<T> {
-	fun add(key: String, value: T): ForgeTagAppender<T>
-	fun addSafe(key: String, value: T): Boolean
-	fun add(key: String, vararg values: T): ForgeTagAppender<T>
-	fun addSafe(key: String, vararg values: T): Boolean {
-		var any = false
-		for (value in values) any = addSafe(key, value)
-		return any
-	}
-
-	fun add(key: String, values: Collection<T>): ForgeTagAppender<T>
-
-	fun addSafe(key: String, values: Collection<T>): Boolean {
-		var any = false
-		for (value in values) any = addSafe(key, value)
-		return any
-	}
-}
-
-private fun <T> vanillaLookup(key: ResourceKey<Registry<T>>): (T) -> ResourceLocation? {
+private fun <T : Any> vanillaLookup(key: ResourceKey<Registry<T>>): (T) -> ResourceLocation {
 	val registry by lazy { (BuiltInRegistries.REGISTRY.get(key.location()) ?: throw NoSuchElementException("No such registry $key")) as Registry<T> }
-	return { registry.getKey(it) }
+	return { registry.getKey(it) ?: throw NoSuchElementException("Registry $key does not contain $it") }
 }
 
-class TagsProvider(
-	private val event: GatherDataEvent
-) {
-	inner class Delegate<T> private constructor(key: ResourceKey<Registry<T>>, val lookup: (T) -> ResourceLocation?) : MinecraftTagsProvider<T>(event.generator.packOutput, key, event.lookupProvider, DataGen.MOD_ID, event.existingFileHelper) {
-		constructor(registry: IForgeRegistry<T>) : this(registry.registryKey, registry::getKey)
+class TagsProvider(private val event: GatherDataEvent) {
+	inner class Delegate<T : Any> private constructor(key: ResourceKey<Registry<T>>, val lookup: (T) -> ResourceLocation) : MinecraftTagsProvider<T>(event.generator.packOutput, key, event.lookupProvider, DataGen.MOD_ID, event.existingFileHelper) {
+		constructor(registry: IForgeRegistry<T>) : this(registry.registryKey, { registry.getKey(it) ?: throw NoSuchElementException("Registry $registry does not contain $it") })
 		constructor(key: ResourceKey<Registry<T>>) : this(key, vanillaLookup(key))
 
 		init {
-			event.generator.addProvider(true, this)
+			if (isRegistered)
+				event.generator.addProvider(event.includeServer(), this)
+			else
+				delegates.add(this)
 		}
 
-		private val tags = HashMap<TagKey<T>, ObjectArraySet<T>>()
+		private val tags = HashMap<TagKey<T>, ObjectArraySet<ResourceLocation>>()
+		private val rigidTags = HashMap<TagKey<T>, ObjectArraySet<ResourceKey<T>>>()
+		private val tagInTag = HashMap<TagKey<T>, ObjectArraySet<TagKey<T>>>()
+
+		inner class Appender(val tag: TagKey<T>) {
+			constructor(tag: ResourceLocation) : this(TagKey.create(registryKey, tag))
+
+			private val locations by lazy { tags.computeIfAbsent(tag) { ObjectArraySet() } }
+			private val rigidLocations by lazy { rigidTags.computeIfAbsent(tag) { ObjectArraySet() } }
+			private val tagsInTags by lazy { tagInTag.computeIfAbsent(tag) { ObjectArraySet() } }
+
+			fun add(value: ResourceLocation): Appender {
+				if (!locations.add(value)) {
+					throw IllegalStateException("Tag $tag of registry $registryKey already contains $value")
+				}
+
+				return this
+			}
+
+			fun add(value: ResourceKey<T>): Appender {
+				require(value.registry() == registryKey) { "Invalid registry in provided ResourceKey: ${value.registry()} (this tag appender is for $registryKey)" }
+
+				if (!rigidLocations.add(value)) {
+					throw IllegalStateException("Tag $tag of registry $registryKey already contains $value")
+				}
+
+				return this
+			}
+
+			fun add(value: TagKey<T>): Appender {
+				require(value.registry() == registryKey) { "Invalid registry in provided ResourceKey: ${value.registry()} (this tag appender is for $registryKey)" }
+
+				if (!tagsInTags.add(value)) {
+					throw IllegalStateException("Tag $tag of registry $registryKey already contains $value")
+				}
+
+				return this
+			}
+
+			fun add(value: T): Appender {
+				return add(ResourceKey.create(registryKey, lookup.invoke(value)))
+			}
+
+			fun add(values: Collection<T>): Appender {
+				for (value in values) add(value)
+				return this
+			}
+
+			fun add(vararg values: T): Appender {
+				for (value in values) add(value)
+				return this
+			}
+
+			fun add(vararg values: ResourceKey<T>): Appender {
+				for (value in values) add(value)
+				return this
+			}
+
+			fun add(vararg values: TagKey<T>): Appender {
+				for (value in values) add(value)
+				return this
+			}
+
+			fun add(vararg values: ResourceLocation): Appender {
+				for (value in values) add(value)
+				return this
+			}
+
+			fun add(values: Stream<T>): Appender {
+				values.forEach { add(it) }
+				return this
+			}
+
+			fun leaf(name: String) = Appender(TagKey.create(tag.registry, ResourceLocation(tag.location.namespace, tag.location.path + "/$name")))
+
+			fun add(leaf: String, value: T) = also { leaf(leaf).add(value) }
+			fun add(leaf: String, value: TagKey<T>) = also { leaf(leaf).add(value) }
+			fun add(leaf: String, vararg value: T) = also { leaf(leaf).add(*value) }
+			fun add(leaf: String, vararg value: TagKey<T>) = also { leaf(leaf).add(*value) }
+			fun add(leaf: String, value: Stream<T>) = also { leaf(leaf).add(value) }
+			fun add(leaf: String, value: ResourceKey<T>) = also { leaf(leaf).add(value) }
+			fun add(leaf: String, vararg value: ResourceKey<T>) = also { leaf(leaf).add(*value) }
+			fun add(leaf: String, value: ResourceLocation) = also { leaf(leaf).add(value) }
+			fun add(leaf: String, vararg value: ResourceLocation) = also { leaf(leaf).add(*value) }
+		}
+
+		fun forge(path: String) = Appender(ResourceLocation("forge", path))
 
 		override fun addTags(provider: HolderLookup.Provider) {
 			if (tags.isEmpty()) {
@@ -85,121 +133,64 @@ class TagsProvider(
 			}
 
 			for ((tag, values) in tags) {
-				tag(tag).also {
-					for (value in values) {
-						it.add(ResourceKey.create(registryKey, lookup(value) ?: throw NoSuchElementException("$value is missing from $registryKey")))
-					}
+				val appender = tag(tag)
+
+				for (value in values) {
+					appender.addOptional(value)
+				}
+			}
+
+			for ((tag, values) in rigidTags) {
+				val appender = tag(tag)
+
+				for (value in values) {
+					appender.add(value)
+				}
+			}
+
+			for ((tag, values) in tagInTag) {
+				val appender = tag(tag)
+
+				for (value in values) {
+					appender.addTag(value)
 				}
 			}
 		}
+	}
 
-		fun getSet(tag: TagKey<T>): MutableSet<T> {
-			return tags.computeIfAbsent(tag) { ObjectArraySet() }
-		}
+	private val delegates = ArrayList<Delegate<*>>()
+	private var isRegistered = false
 
-		fun getSet(location: ResourceLocation) = getSet(TagKey.create(registryKey, location))
+	fun register() {
+		if (!isRegistered) {
+			isRegistered = true
 
-		fun appender(tag: TagKey<T>, message: ((T) -> Any) = { "$it is already in $tag" }): MTagAppender<T> {
-			val list = getSet(tag)
-
-			return object : MTagAppender<T> {
-				override fun add(value: T): MTagAppender<T> {
-					if (!list.add(value)) {
-						throw IllegalStateException(message.invoke(value).toString())
-					}
-
-					return this
-				}
-
-				override fun add(values: Collection<T>): MTagAppender<T> {
-					for (value in values) add(value)
-					return this
-				}
-
-				override fun addSafe(value: T): Boolean {
-					return list.add(value)
-				}
-
-				override fun add(vararg values: T): MTagAppender<T> {
-					values.forEach(this::add)
-					return this
-				}
+			for (value in delegates) {
+				event.generator.addProvider(event.includeServer(), value)
 			}
-		}
 
-		fun forge(path: String): ForgeTagAppender<T> {
-			val parent by lazy { appender(ResourceLocation("forge", path)) }
-
-			return object : ForgeTagAppender<T> {
-				override fun add(key: String, value: T): ForgeTagAppender<T> {
-					val tag = TagKey.create(registryKey, ResourceLocation("forge", "$path/$key"))
-
-					if (!getSet(tag).add(value)) {
-						throw IllegalStateException("$value is already in $tag")
-					}
-
-					return this
-				}
-
-				override fun addSafe(key: String, value: T): Boolean {
-					val tag = TagKey.create(registryKey, ResourceLocation("forge", "$path/$key"))
-					return getSet(tag).add(value)
-				}
-
-				override fun add(key: String, vararg values: T): ForgeTagAppender<T> {
-					for (value in values) add(key, value)
-					return this
-				}
-
-				override fun add(key: String, values: Collection<T>): ForgeTagAppender<T> {
-					for (value in values) add(key, value)
-					return this
-				}
-
-				override fun add(value: T): MTagAppender<T> {
-					return parent.add(value)
-				}
-
-				override fun addSafe(value: T): Boolean {
-					return parent.addSafe(value)
-				}
-
-				override fun add(vararg values: T): MTagAppender<T> {
-					return parent.add(*values)
-				}
-
-				override fun add(values: Collection<T>): MTagAppender<T> {
-					return parent.add(values)
-				}
-			}
-		}
-
-		fun appender(location: ResourceLocation): MTagAppender<T> {
-			return appender(TagKey.create(registryKey, location))
-		}
-
-		fun appender(location: ResourceLocation, message: (T) -> Any): MTagAppender<T> {
-			return appender(TagKey.create(registryKey, location), message)
+			delegates.clear()
 		}
 	}
 
 	val blocks = Delegate(ForgeRegistries.BLOCKS)
 	val items = Delegate(ForgeRegistries.ITEMS)
 	val mobEffects = Delegate(ForgeRegistries.MOB_EFFECTS)
+	val damageTypes = Delegate(Registries.DAMAGE_TYPE)
 
-	val androidImmuneEffects = mobEffects.appender(MatteryPlayerCapability.ANDROID_IMMUNE_EFFECTS)
+	val androidImmuneEffects = mobEffects.Appender(MatteryPlayerCapability.ANDROID_IMMUNE_EFFECTS)
 
-	val requiresShovel = blocks.appender(BlockTags.MINEABLE_WITH_SHOVEL)
-	val requiresAxe = blocks.appender(BlockTags.MINEABLE_WITH_AXE)
-	val requiresHoe = blocks.appender(BlockTags.MINEABLE_WITH_HOE)
-	val requiresPickaxe = blocks.appender(BlockTags.MINEABLE_WITH_PICKAXE)
+	val requiresShovel = blocks.Appender(BlockTags.MINEABLE_WITH_SHOVEL)
+	val requiresAxe = blocks.Appender(BlockTags.MINEABLE_WITH_AXE)
+	val requiresHoe = blocks.Appender(BlockTags.MINEABLE_WITH_HOE)
+	val requiresPickaxe = blocks.Appender(BlockTags.MINEABLE_WITH_PICKAXE)
 
-	val requiresStoneTool = blocks.appender(BlockTags.NEEDS_STONE_TOOL)
-	val requiresIronTool = blocks.appender(BlockTags.NEEDS_IRON_TOOL)
-	val requiresDiamondTool = blocks.appender(BlockTags.NEEDS_DIAMOND_TOOL)
+	val requiresStoneTool = blocks.Appender(BlockTags.NEEDS_STONE_TOOL)
+	val requiresIronTool = blocks.Appender(BlockTags.NEEDS_IRON_TOOL)
+	val requiresDiamondTool = blocks.Appender(BlockTags.NEEDS_DIAMOND_TOOL)
 
-	val witherImmune = blocks.appender(BlockTags.WITHER_IMMUNE)
-	val dragonImmune = blocks.appender(BlockTags.DRAGON_IMMUNE)
+	val witherImmune = blocks.Appender(BlockTags.WITHER_IMMUNE)
+	val dragonImmune = blocks.Appender(BlockTags.DRAGON_IMMUNE)
 
 	fun stoneOre(key: String, block: Block): TagsProvider {
 		ore(key, block)
@@ -233,9 +224,9 @@ class TagsProvider(
 		val b = TagKey.create(Registries.BLOCK, forgeKey)
 		val i = TagKey.create(Registries.ITEM, forgeKey)
 
-		items.getSet(i).add(block.asItem())
+		items.Appender(i).add(block.asItem())
 		itemOres.add(block.asItem())
-		blocks.getSet(b).add(block)
+		blocks.Appender(b).add(block)
 		blockOres.add(block)
 
 		return this
@@ -286,7 +277,7 @@ class TagsProvider(
 //	val itemOreRatesDense = items.forge("ore_rates/dense")
 
 	val gameEvents = Delegate(Registries.GAME_EVENT)
-	val vibrations = gameEvents.appender(GameEventTags.VIBRATIONS)
+	val vibrations = gameEvents.Appender(GameEventTags.VIBRATIONS)
 
 	fun requiresPickaxe(block: Block, tier: Tier? = null): TagsProvider {
 		requiresPickaxe.add(block)