diff --git a/README.md b/README.md
index 6f2485f..8c91d19 100644
--- a/README.md
+++ b/README.md
@@ -99,6 +99,7 @@ entity_builder:build :: entity, boolean
 ```
 fragment :: fragment_builder
 fragment_builder:tag :: fragment_builder
+fragment_builder:single :: component -> fragment_builder
 fragment_builder:default :: component -> fragment_builder
 fragment_builder:construct :: {any... -> component} -> fragment_builder
 fragment_builder:on_set :: {entity, fragment, component, component?} -> fragment_builder
diff --git a/ROADMAP.md b/ROADMAP.md
index 4c1c05a..c18655c 100644
--- a/ROADMAP.md
+++ b/ROADMAP.md
@@ -2,7 +2,8 @@
 
 ## Backlog
 
-- try to keep entity_chunks/places tables as arrays
+- INDEX fragment trait
+- phase/pipeline addon
 
 ## After first release
 
@@ -10,3 +11,5 @@
 - add REQUIRES fragment trait
 - use compact prefix-tree for chunks
 - set/assign/insert/remove/clear/destroy for lists
+- optional ffi component storages
+- keep entity_chunks/places tables as arrays
diff --git a/develop/untests.lua b/develop/untests.lua
index be3cad6..7e19f70 100644
--- a/develop/untests.lua
+++ b/develop/untests.lua
@@ -6508,3 +6508,20 @@ do
         assert(evo.select(c3, f3)[3] == 3 and evo.select(c3, f3)[4] == 33)
     end
 end
+
+do
+    do
+        local f = evo.fragment():default():build()
+        assert(not evo.has(f, evo.DEFAULT))
+    end
+
+    do
+        local f = evo.fragment():single():build()
+        assert(not evo.has(f, f))
+    end
+
+    do
+        local f = evo.fragment():single(42):build()
+        assert(evo.has(f, f) and evo.get(f, f) == 42)
+    end
+end
diff --git a/evolved.lua b/evolved.lua
index d771425..ad785b3 100644
--- a/evolved.lua
+++ b/evolved.lua
@@ -5044,7 +5044,7 @@ function evolved.batch_set(query, fragment, ...)
     end
     __defer_commit()
 
-    __release_table(__TABLE_POOL_TAG__CHUNK_STACK, chunk_list, true)
+    __release_table(__TABLE_POOL_TAG__CHUNK_STACK, chunk_list)
     return set_count, false
 end
 
@@ -5079,7 +5079,7 @@ function evolved.batch_assign(query, fragment, ...)
     end
     __defer_commit()
 
-    __release_table(__TABLE_POOL_TAG__CHUNK_STACK, chunk_list, true)
+    __release_table(__TABLE_POOL_TAG__CHUNK_STACK, chunk_list)
     return assigned_count, false
 end
 
@@ -5114,7 +5114,7 @@ function evolved.batch_insert(query, fragment, ...)
     end
     __defer_commit()
 
-    __release_table(__TABLE_POOL_TAG__CHUNK_STACK, chunk_list, true)
+    __release_table(__TABLE_POOL_TAG__CHUNK_STACK, chunk_list)
     return inserted_count, false
 end
 
@@ -5148,7 +5148,7 @@ function evolved.batch_remove(query, ...)
     end
     __defer_commit()
 
-    __release_table(__TABLE_POOL_TAG__CHUNK_STACK, chunk_list, true)
+    __release_table(__TABLE_POOL_TAG__CHUNK_STACK, chunk_list)
     return removed_count, false
 end
 
@@ -5181,7 +5181,7 @@ function evolved.batch_clear(query)
     end
     __defer_commit()
 
-    __release_table(__TABLE_POOL_TAG__CHUNK_STACK, chunk_list, true)
+    __release_table(__TABLE_POOL_TAG__CHUNK_STACK, chunk_list)
     return cleared_count, false
 end
 
@@ -5214,7 +5214,7 @@ function evolved.batch_destroy(query)
     end
     __defer_commit()
 
-    __release_table(__TABLE_POOL_TAG__CHUNK_STACK, chunk_list, true)
+    __release_table(__TABLE_POOL_TAG__CHUNK_STACK, chunk_list)
     return destroyed_count, false
 end
 
@@ -5253,7 +5253,7 @@ function evolved.batch_multi_set(query, fragments, components)
     end
     __defer_commit()
 
-    __release_table(__TABLE_POOL_TAG__CHUNK_STACK, chunk_list, true)
+    __release_table(__TABLE_POOL_TAG__CHUNK_STACK, chunk_list)
     return set_count, false
 end
 
@@ -5292,7 +5292,7 @@ function evolved.batch_multi_assign(query, fragments, components)
     end
     __defer_commit()
 
-    __release_table(__TABLE_POOL_TAG__CHUNK_STACK, chunk_list, true)
+    __release_table(__TABLE_POOL_TAG__CHUNK_STACK, chunk_list)
     return assigned_count, false
 end
 
@@ -5331,7 +5331,7 @@ function evolved.batch_multi_insert(query, fragments, components)
     end
     __defer_commit()
 
-    __release_table(__TABLE_POOL_TAG__CHUNK_STACK, chunk_list, true)
+    __release_table(__TABLE_POOL_TAG__CHUNK_STACK, chunk_list)
     return inserted_count, false
 end
 
@@ -5365,7 +5365,7 @@ function evolved.batch_multi_remove(query, fragments)
     end
     __defer_commit()
 
-    __release_table(__TABLE_POOL_TAG__CHUNK_STACK, chunk_list, true)
+    __release_table(__TABLE_POOL_TAG__CHUNK_STACK, chunk_list)
     return removed_count, false
 end
 
@@ -5696,6 +5696,7 @@ end
 
 ---@class (evact) evolved.__fragment_builder
 ---@field package __tag boolean
+---@field package __single? evolved.component
 ---@field package __default? evolved.component
 ---@field package __construct? fun(...): evolved.component
 ---@field package __on_set? evolved.set_hook
@@ -5713,6 +5714,7 @@ function evolved.fragment()
     ---@type evolved.__fragment_builder
     local builder = {
         __tag = false,
+        __single = nil,
         __default = nil,
         __construct = nil,
         __on_set = nil,
@@ -5730,6 +5732,13 @@ function evolved_fragment_builder:tag()
     return self
 end
 
+---@param single evolved.component
+---@return evolved.fragment_builder builder
+function evolved_fragment_builder:single(single)
+    self.__single = single
+    return self
+end
+
 ---@param default evolved.component
 ---@return evolved.fragment_builder builder
 function evolved_fragment_builder:default(default)
@@ -5776,6 +5785,7 @@ end
 ---@return boolean is_deferred
 function evolved_fragment_builder:build()
     local tag = self.__tag
+    local single = self.__single
     local default = self.__default
     local construct = self.__construct
 
@@ -5785,6 +5795,7 @@ function evolved_fragment_builder:build()
     local on_remove = self.__on_remove
 
     self.__tag = false
+    self.__single = nil
     self.__default = nil
     self.__construct = nil
 
@@ -5793,6 +5804,8 @@ function evolved_fragment_builder:build()
     self.__on_insert = nil
     self.__on_remove = nil
 
+    local fragment = evolved.id()
+
     local fragment_list = __acquire_table(__TABLE_POOL_TAG__FRAGMENT_LIST)
     local component_list = __acquire_table(__TABLE_POOL_TAG__COMPONENT_LIST)
     local component_count = 0
@@ -5803,6 +5816,12 @@ function evolved_fragment_builder:build()
         component_list[component_count] = true
     end
 
+    if single ~= nil then
+        component_count = component_count + 1
+        fragment_list[component_count] = fragment
+        component_list[component_count] = single
+    end
+
     if default ~= nil then
         component_count = component_count + 1
         fragment_list[component_count] = evolved.DEFAULT
@@ -5843,7 +5862,7 @@ function evolved_fragment_builder:build()
         return evolved.id(), false
     end
 
-    local fragment, is_deferred = evolved.spawn_with(fragment_list, component_list)
+    local _, is_deferred = evolved.multi_set(fragment, fragment_list, component_list)
 
     __release_table(__TABLE_POOL_TAG__FRAGMENT_LIST, fragment_list)
     __release_table(__TABLE_POOL_TAG__COMPONENT_LIST, component_list)