diff --git a/jecs/build.txt b/jecs/build.txt
index f754d8c..e3fde5a 100644
--- a/jecs/build.txt
+++ b/jecs/build.txt
@@ -1,2 +1,2 @@
-modified = ["jecs.luau"]
-version = "0.5.5-nightly.20250427T001102Z"
+modified = ["addons/observers.luau", "CHANGELOG.md", "jecs.luau"]
+version = "0.5.5-nightly.20250426T001101Z"
diff --git a/jecs/jecs.luau b/jecs/jecs.luau
index 7bfeb68..94415af 100644
--- a/jecs/jecs.luau
+++ b/jecs/jecs.luau
@@ -1437,24 +1437,19 @@ local function world_delete(world: ecs_world_t, entity: i53)
 	end
 
 	local dense_array = entity_index.dense_array
-	local dense = record.dense
-	local i_swap = entity_index.alive_count
-	entity_index.alive_count = i_swap - 1
+	local index_of_deleted_entity = record.dense
+	local index_of_last_alive_entity = entity_index.alive_count
+	entity_index.alive_count = index_of_last_alive_entity - 1
 
-	local e_swap = dense_array[i_swap]
-	local r_swap = entity_index_try_get_any(entity_index, e_swap) :: ecs_record_t
-
-	r_swap.dense = dense
+	local last_alive_entity = dense_array[index_of_last_alive_entity]
+	local r_swap = entity_index_try_get_any(entity_index, last_alive_entity) :: ecs_record_t
+	r_swap.dense = index_of_deleted_entity
 	record.archetype = nil :: any
 	record.row = nil :: any
-	record.dense = i_swap
+	record.dense = index_of_last_alive_entity
 
-	dense_array[dense] = e_swap
-	dense_array[i_swap] = ECS_GENERATION_INC(entity)
-end
-
-local function world_exists(world: ecs_world_t, entity): boolean
-	return entity_index_try_get_any(world.entity_index, entity) ~= nil
+	dense_array[index_of_deleted_entity] = last_alive_entity
+	dense_array[index_of_last_alive_entity] = ECS_GENERATION_INC(entity)
 end
 
 local function world_contains(world: ecs_world_t, entity): boolean
@@ -2448,7 +2443,6 @@ World.has = world_has
 World.target = world_target
 World.parent = world_parent
 World.contains = world_contains
-World.exists = world_exists
 World.cleanup = world_cleanup
 World.each = world_each
 World.children = world_children
@@ -2488,6 +2482,12 @@ local function world_new()
 		entity_index_new_id(entity_index)
 	end
 
+	for i = EcsRest + 1, ecs_max_tag_id do
+		-- Initialize built-in components
+		entity_index_new_id(entity_index)
+		print("hm...", i)
+	end
+
 	world_add(self, EcsName, EcsComponent)
 	world_add(self, EcsOnChange, EcsComponent)
 	world_add(self, EcsOnAdd, EcsComponent)
@@ -2510,10 +2510,6 @@ local function world_new()
 
 	world_add(self, EcsChildOf, ECS_PAIR(EcsOnDeleteTarget, EcsDelete))
 
-	for i = EcsRest + 1, ecs_max_tag_id do
-		entity_index_new_id(entity_index)
-	end
-
 	for i, bundle in ecs_metadata do
 		for ty, value in bundle do
 			if value == NULL then
@@ -2616,9 +2612,6 @@ export type World = {
 	--- Checks if the world contains the given entity
 	contains:(self: World, entity: Entity) -> boolean,
 
-	--- Checks if the entity exists
-	exists: (self: World, entity: Entity) -> boolean,
-
 	each: <T>(self: World, id: Id<T>) -> () -> Entity,
 
 	children: <T>(self: World, id: Id<T>) -> () -> Entity,
diff --git a/jecs/pesde-rbx.toml b/jecs/pesde-rbx.toml
index 3b3b005..e575978 100644
--- a/jecs/pesde-rbx.toml
+++ b/jecs/pesde-rbx.toml
@@ -3,7 +3,7 @@ includes = ["init.luau", "pesde.toml", "README.md", "CHANGELOG.md", "LICENSE", "
 license = "MIT"
 name = "marked/jecs_nightly"
 repository = "https://git.devmarked.win/marked/jecs-nightly"
-version = "0.5.5-nightly.20250427T001102Z"
+version = "0.5.5-nightly.20250426T001101Z"
 
 [indices]
 default = "https://github.com/pesde-pkg/index"
diff --git a/jecs/pesde.toml b/jecs/pesde.toml
index 6c79fa2..cba3853 100644
--- a/jecs/pesde.toml
+++ b/jecs/pesde.toml
@@ -3,7 +3,7 @@ includes = ["init.luau", "pesde.toml", "README.md", "CHANGELOG.md", "LICENSE", "
 license = "MIT"
 name = "marked/jecs_nightly"
 repository = "https://git.devmarked.win/marked/jecs-nightly"
-version = "0.5.5-nightly.20250427T001102Z"
+version = "0.5.5-nightly.20250426T001101Z"
 
 [indices]
 default = "https://github.com/pesde-pkg/index"
diff --git a/jecs/test.txt b/jecs/test.txt
index 05f27df..67f4934 100644
--- a/jecs/test.txt
+++ b/jecs/test.txt
@@ -1,2 +1,2 @@
 passed = true
-timestamp = "20250427T001104Z"
+timestamp = "20250426T001103Z"
diff --git a/jecs/test_fulllog.txt b/jecs/test_fulllog.txt
index d10e2fa..89c1324 100644
--- a/jecs/test_fulllog.txt
+++ b/jecs/test_fulllog.txt
@@ -1,5 +1,6 @@
-7.2 us   2 kB│ delete children of entity
-9.2 us   1 kB│ remove friends of entity
+hm...	271
+7.7 us   3 kB│ delete children of entity
+9.3 us   1 kB│ remove friends of entity
 349 ns   0  B│ simple deletion of entity
 *created e1000v0
 world:add()
@@ -118,5 +119,5 @@
 PASS│ #2
 PASS│ #3
 
-72/72 test cases passed in 32.525 ms.
+72/72 test cases passed in 31.076 ms.
 0 fails
diff --git a/jecs/wally.toml b/jecs/wally.toml
index 2ebd701..d23c40e 100644
--- a/jecs/wally.toml
+++ b/jecs/wally.toml
@@ -5,4 +5,4 @@ license = "MIT"
 name = "mark-marks/jecs-nightly"
 realm = "shared"
 registry = "https://github.com/UpliftGames/wally-index"
-version = "0.5.5-nightly.20250427T001102Z"
+version = "0.5.5-nightly.20250426T001101Z"