diff --git a/include/ecs.h b/include/ecs.h
index 88fc0c1..2b09168 100644
--- a/include/ecs.h
+++ b/include/ecs.h
@@ -4,4 +4,5 @@
 #include "./ecs/settings.h"
 #include "./ecs/signature_list.h"
 #include "./ecs/signature.h"
+#include "./ecs/system_execution_adapter.h"
 #include "./ecs/tag.h"
\ No newline at end of file
diff --git a/include/ecs/config.h b/include/ecs/config.h
index b464106..6aabb8a 100644
--- a/include/ecs/config.h
+++ b/include/ecs/config.h
@@ -65,6 +65,9 @@ struct type_helper
 #define beg_namespace_ecs_core_parallelism              ecs_define_namespace_beg(beg_namespace_ecs_core_system, parallelism)
 #define end_namespace_ecs_core_parallelism              ecs_define_namespace_end(end_namespace_ecs_core_system)
 
+#define beg_namespace_ecs_core_system_scheduler         ecs_define_namespace_beg(beg_namespace_ecs_core_system, scheduler)
+#define end_namespace_ecs_core_system_scheduler         ecs_define_namespace_end(end_namespace_ecs_core_system)
+
 #define beg_namespace_ecs_core_system_storage           ecs_define_namespace_beg(beg_namespace_ecs_core_system, storage)
 #define end_namespace_ecs_core_system_storage           ecs_define_namespace_end(end_namespace_ecs_core_system)
 
@@ -80,6 +83,9 @@ struct type_helper
 #define beg_namespace_ecs_settings_refresh_parallelism  ecs_define_namespace_beg(beg_namespace_ecs_settings, refresh_parallelism)
 #define end_namespace_ecs_settings_refresh_parallelism  ecs_define_namespace_end(end_namespace_ecs_settings)
 
+#define beg_namespace_ecs_settings_scheduler            ecs_define_namespace_beg(beg_namespace_ecs_settings, scheduler)
+#define end_namespace_ecs_settings_scheduler            ecs_define_namespace_end(end_namespace_ecs_settings)
+
 #define beg_namespace_ecs_settings_system_storage       ecs_define_namespace_beg(beg_namespace_ecs_settings, system_storage)
 #define end_namespace_ecs_settings_system_storage       ecs_define_namespace_end(end_namespace_ecs_settings)
 
@@ -110,6 +116,9 @@ struct type_helper
 #define beg_namespace_ecs_signature_list_system         ecs_define_namespace_beg(beg_namespace_ecs_signature_list, system)
 #define end_namespace_ecs_signature_list_system         ecs_define_namespace_end(end_namespace_ecs_signature_list)
 
+#define beg_namespace_ecs_system_execution_adapter      ecs_define_namespace_beg(beg_namespace_ecs, system_execution_adapter)
+#define end_namespace_ecs_system_execution_adapter      ecs_define_namespace_end(end_namespace_ecs)
+
 #define beg_namespace_ecs_tag                           ecs_define_namespace_beg(beg_namespace_ecs, tag)
 #define end_namespace_ecs_tag                           ecs_define_namespace_end(end_namespace_ecs)
 
diff --git a/include/ecs/context.h b/include/ecs/context.h
index f4055ef..0356e14 100644
--- a/include/ecs/context.h
+++ b/include/ecs/context.h
@@ -1,3 +1,6 @@
 #pragma once
 
-#include "./context/context.h"
\ No newline at end of file
+#include "./context/base.h"
+#include "./context/context.h"
+#include "./context/defer_proxy.h"
+#include "./context/step_proxy.h"
\ No newline at end of file
diff --git a/include/ecs/context/base.h b/include/ecs/context/base.h
index 766a78b..07adb96 100644
--- a/include/ecs/context/base.h
+++ b/include/ecs/context/base.h
@@ -5,6 +5,12 @@
 #include <ecs/core/utils/counter_blocker.h>
 #include <ecs/core/component/manager.h>
 
+#define ecs_context_proxy_func(base, name)                              \
+    template<typename... T_args>                                        \
+    inline decltype(auto) name(T_args&&... args)                        \
+        noexcept(noexcept(base::name(std::forward<T_args>(args)...)))   \
+        { return base::name(std::forward<T_args>(args)...); }
+
 beg_namespace_ecs_context
 {
 
@@ -22,6 +28,7 @@ beg_namespace_ecs_context
             using entity_storage_type       = decltype((settings_type { }).entity_storage()(settings_type { }, hana::type_c<chunk_meta_data_type>));
             using entity_handle_type        = typename entity_storage_type::entity_handle_type;
             using system_storage_type       = decltype((settings_type { }).system_storage()(settings_type { }, hana::type_c<entity_handle_type>));
+            using scheduler_type            = decltype((settings_type { }).scheduler()(settings_type { }));
 
         public:
             using handle_type               = entity_handle_type;
@@ -33,6 +40,7 @@ beg_namespace_ecs_context
             component_manager_type      _components;
             entity_storage_type         _entities;
             system_storage_type         _systems;
+            scheduler_type              _scheduler;
 
             core::utils::thread_pool    _thread_pool;
 
@@ -42,21 +50,22 @@ beg_namespace_ecs_context
         public:
             inline base_t()
                 : _components   ()
-                , _entities     (settings_type { }.entity_storage()(settings_type { }, hana::type_c<chunk_meta_data_type>))
-                , _systems      (settings_type { }.system_storage()(settings_type { }, hana::type_c<entity_handle_type>))
+                , _entities     ((settings_type { }).entity_storage()(settings_type { }, hana::type_c<chunk_meta_data_type>))
+                , _systems      ((settings_type { }).system_storage()(settings_type { }, hana::type_c<entity_handle_type>))
+                , _scheduler    ((settings_type { }).scheduler()(settings_type { }))
                 , _thread_pool  (std::thread::hardware_concurrency() != 0
                                     ? std::thread::hardware_concurrency()
                                     : 8 )
                 { }
 
-        public: /* misc */
+        protected: /* misc */
             template<typename T_func>
             inline decltype(auto) post_in_thread_pool(T_func&& func)
             {
                 return _thread_pool.post(std::forward<T_func>(func));
             }
 
-        public: /* entity */
+        protected: /* entity */
             template<typename... T_args>
             inline handle_type create_entity(T_args&&... args)
             {
@@ -74,7 +83,7 @@ beg_namespace_ecs_context
                 return _entities.is_valid(handle);
             }
 
-        public: /* component */
+        protected: /* component */
             template<typename T_component_tag>
             inline decltype(auto) add_component(const handle_type& handle, T_component_tag ct)
             {
@@ -115,7 +124,13 @@ beg_namespace_ecs_context
                 bitset.set_component(ct, false);
             }
 
-        public: /* systems */
+        protected: /* systems */
+            template<typename T_system_tag>
+            inline auto& system(T_system_tag st)
+            {
+                return _systems.instance_by_tag(st).system();
+            }
+
             template<typename T_func>
             inline void for_systems_sequential(T_func&& func)
             {
@@ -150,6 +165,28 @@ beg_namespace_ecs_context
                         _(this)->for_systems_sequential(func);
                     });
             }
+
+        private:
+            template<typename... T_system_tags>
+            static constexpr decltype(auto) make_system_tag_list(T_system_tags&&... tags) noexcept
+            {
+                auto list = core::mp::list::make(std::forward<T_system_tags>(tags)...);
+                return hana::if_(
+                    hana::equal(hana::size(list), hana::size_c<0>),
+                    (settings_type { }).system_signatures().tags(),
+                    list);
+            }
+
+        protected: /* execute */
+            template<typename... T_system_tags>
+            inline decltype(auto) execute_systems(T_system_tags&&... sts) noexcept
+            {
+                auto tags = make_system_tag_list(std::forward<T_system_tags>(sts)...);
+                return [tags, this](auto&&... fns) {
+                    auto os = hana::overload_linearly(std::forward<decltype(fns)>(fns)...);
+                    this->_scheduler.execute(*this, tags, os);
+                };
+            }
         };
     }
 
diff --git a/include/ecs/context/context.h b/include/ecs/context/context.h
index 2dd1fec..92ab991 100644
--- a/include/ecs/context/context.h
+++ b/include/ecs/context/context.h
@@ -3,7 +3,7 @@
 #include <ecs/config.h>
 #include <ecs/core/utils/scope_guard.h>
 
-#include "./base.h"
+#include "./step_proxy.h"
 
 beg_namespace_ecs_context
 {
@@ -12,8 +12,12 @@ beg_namespace_ecs_context
     {
         template<typename T_settings>
         struct context_t
-            : public base_t<T_settings>
+            : public step_proxy_t<T_settings>
         {
+        private:
+            using settings_type   = T_settings;
+            using step_proxy_type = step_proxy_t<settings_type>;
+
         private:
             void refresh()
             {
@@ -22,11 +26,13 @@ beg_namespace_ecs_context
 
         public:
             template<typename T_step_func>
-            inline decltype(auto) step(T_step_func&& set_func)
+            inline decltype(auto) step(T_step_func&& step_func)
             {
                 ecs_make_scope_guard([this]{
                     this->refresh();
                 });
+
+                std::forward<T_step_func>(step_func)(static_cast<step_proxy_type&>(*this));
             }
         };
 
diff --git a/include/ecs/context/defer_proxy.h b/include/ecs/context/defer_proxy.h
new file mode 100644
index 0000000..c0d8f4c
--- /dev/null
+++ b/include/ecs/context/defer_proxy.h
@@ -0,0 +1,36 @@
+#pragma once
+
+#include <ecs/config.h>
+
+#include "./base.h"
+
+beg_namespace_ecs_context
+{
+
+    namespace __impl
+    {
+        template<typename T_settings>
+        struct defer_proxy_t
+            : public base_t<T_settings>
+        {
+        private:
+            using base_type = base_t<T_settings>;
+
+        public: /* entity */
+            ecs_context_proxy_func(base_type, create_entity)
+            ecs_context_proxy_func(base_type, kill_entity)
+            ecs_context_proxy_func(base_type, is_alive)
+
+        public: /* component */
+            ecs_context_proxy_func(base_type, add_component)
+            ecs_context_proxy_func(base_type, has_component)
+            ecs_context_proxy_func(base_type, get_component)
+            ecs_context_proxy_func(base_type, remove_component)
+
+        public: /* system */
+            ecs_context_proxy_func(base_type, system)
+        };
+    }
+
+}
+end_namespace_ecs_context
\ No newline at end of file
diff --git a/include/ecs/context/step_proxy.h b/include/ecs/context/step_proxy.h
new file mode 100644
index 0000000..8628f70
--- /dev/null
+++ b/include/ecs/context/step_proxy.h
@@ -0,0 +1,25 @@
+#pragma once
+
+#include <ecs/config.h>
+
+#include "./defer_proxy.h"
+
+beg_namespace_ecs_context
+{
+
+    namespace __impl
+    {
+        template<typename T_settings>
+        struct step_proxy_t
+            : public defer_proxy_t<T_settings>
+        {
+        private:
+            using base_type = defer_proxy_t<T_settings>;
+
+        public: /* execute */
+            ecs_context_proxy_func(base_type, execute_systems)
+        };
+    }
+
+}
+end_namespace_ecs_context
\ No newline at end of file
diff --git a/include/ecs/core/system.h b/include/ecs/core/system.h
index 485d51a..4173afe 100644
--- a/include/ecs/core/system.h
+++ b/include/ecs/core/system.h
@@ -2,4 +2,5 @@
 
 #include "./system/instance.h"
 #include "./system/parallelism.h"
+#include "./system/scheduler.h"
 #include "./system/storage.h"
\ No newline at end of file
diff --git a/include/ecs/core/system/scheduler.h b/include/ecs/core/system/scheduler.h
new file mode 100644
index 0000000..d2082ba
--- /dev/null
+++ b/include/ecs/core/system/scheduler.h
@@ -0,0 +1,3 @@
+#pragma once
+
+#include "./scheduler/atomic_counter.h"
\ No newline at end of file
diff --git a/include/ecs/core/system/scheduler/atomic_counter.h b/include/ecs/core/system/scheduler/atomic_counter.h
new file mode 100644
index 0000000..e346a13
--- /dev/null
+++ b/include/ecs/core/system/scheduler/atomic_counter.h
@@ -0,0 +1,21 @@
+#pragma once
+
+#include <ecs/config.h>
+
+beg_namespace_ecs_core_system_scheduler
+{
+
+    template<typename T_settings>
+    struct atomic_counter
+    {
+    public:
+        using settings_type = T_settings;
+
+    public:
+        template<typename... T_args>
+        inline void execute(T_args&&...)
+            { }
+    };
+
+}
+end_namespace_ecs_core_system_scheduler
\ No newline at end of file
diff --git a/include/ecs/settings/scheduler.h b/include/ecs/settings/scheduler.h
new file mode 100644
index 0000000..d2082ba
--- /dev/null
+++ b/include/ecs/settings/scheduler.h
@@ -0,0 +1,3 @@
+#pragma once
+
+#include "./scheduler/atomic_counter.h"
\ No newline at end of file
diff --git a/include/ecs/settings/scheduler/atomic_counter.h b/include/ecs/settings/scheduler/atomic_counter.h
new file mode 100644
index 0000000..422cb1c
--- /dev/null
+++ b/include/ecs/settings/scheduler/atomic_counter.h
@@ -0,0 +1,22 @@
+#pragma once
+
+#include <ecs/config.h>
+#include <ecs/core/system/scheduler/atomic_counter.h>
+
+beg_namespace_ecs_settings_scheduler
+{
+
+    namespace __impl
+    {
+        struct atomic_counter_t
+        {
+            template<typename T_settings>
+            constexpr decltype(auto) operator()(T_settings) const noexcept
+                { return core::system::scheduler::atomic_counter<T_settings> { }; }
+        };
+    }
+
+    constexpr decltype(auto) atomic_counter = __impl::atomic_counter_t { };
+
+}
+end_namespace_ecs_settings_scheduler
\ No newline at end of file
diff --git a/include/ecs/settings/settings.h b/include/ecs/settings/settings.h
index 2554a19..36ed8f0 100644
--- a/include/ecs/settings/settings.h
+++ b/include/ecs/settings/settings.h
@@ -7,6 +7,7 @@
 #include "./system_storage.h"
 #include "./entity_storage.h"
 #include "./refresh_parallelism.h"
+#include "./scheduler.h"
 
 beg_namespace_ecs_settings
 {
@@ -18,6 +19,7 @@ beg_namespace_ecs_settings
         constexpr decltype(auto) system_storage       = hana::size_c<2>;
         constexpr decltype(auto) entity_storage       = hana::size_c<3>;
         constexpr decltype(auto) refresh_parallelism  = hana::size_c<4>;
+        constexpr decltype(auto) scheduler            = hana::size_c<5>;
     }
 
     namespace __impl
@@ -53,6 +55,9 @@ beg_namespace_ecs_settings
             constexpr decltype(auto) refresh_parallelism() const noexcept
                 { return get(keys::refresh_parallelism); }
 
+            constexpr decltype(auto) scheduler() const noexcept
+                { return get(keys::scheduler); }
+
         public: /* setter */
             template<typename T>
             constexpr decltype(auto) component_signatures(T t) const noexcept
@@ -73,6 +78,10 @@ beg_namespace_ecs_settings
             template<typename T>
             constexpr decltype(auto) refresh_parallelism(T t) const noexcept
                 { return change(keys::refresh_parallelism, t); }
+
+            template<typename T>
+            constexpr decltype(auto) scheduler(T t) const noexcept
+                { return change(keys::scheduler, t); }
         };
 
         struct make_t
@@ -85,7 +94,8 @@ beg_namespace_ecs_settings
                     .add(keys::system_signatures,    list::empty)
                     .add(keys::system_storage,       system_storage::tuple)
                     .add(keys::entity_storage,       entity_storage::dynamic<1024>)
-                    .add(keys::refresh_parallelism,  refresh_parallelism::enable);
+                    .add(keys::refresh_parallelism,  refresh_parallelism::enable)
+                    .add(keys::scheduler,            scheduler::atomic_counter);
                 return settings_t<decay_t<decltype(options)>> { };
             }
         };
diff --git a/include/ecs/signature_list/system.h b/include/ecs/signature_list/system.h
index 28b00e8..510eeed 100644
--- a/include/ecs/signature_list/system.h
+++ b/include/ecs/signature_list/system.h
@@ -20,6 +20,15 @@ beg_namespace_ecs_signature_list_system
                 { return hana::size(items); }
 
         public: /* get */
+            constexpr decltype(auto) tags() const noexcept
+            {
+                return hana::unpack(
+                    hana::transform(items, [](auto& ssig){
+                        return core::mp::unwrap(ssig).tag();
+                    }),
+                    core::mp::list::make);
+            }
+
             template<typename T_system_tag>
             constexpr decltype(auto) get_by_tag(T_system_tag st) const noexcept
             {
diff --git a/include/ecs/system_execution_adapter.h b/include/ecs/system_execution_adapter.h
new file mode 100644
index 0000000..09fb579
--- /dev/null
+++ b/include/ecs/system_execution_adapter.h
@@ -0,0 +1,77 @@
+#pragma once
+
+#include <ecs/config.h>
+
+beg_namespace_ecs_system_execution_adapter
+{
+
+    namespace __impl
+    {
+        template<typename T_predicate>
+        struct predicate_holder
+        {
+        private:
+            using predicate_type = T_predicate;
+
+            template<typename T_instance>
+            using predicate_result_type = decltype(
+                std::declval<predicate_type>()(
+                    std::declval<core::mp::decay_t<T_instance>>().system()));
+
+            template<typename T_predicate_result>
+            using enabler = std::enable_if_t<T_predicate_result { }, void>;
+
+        public:
+            template<typename T_func>
+            constexpr decltype(auto) detailed_instance(T_func&& func) noexcept
+            {
+                return [f = std::forward<T_func>(func)](auto& instance, auto& executor)
+                    -> enabler<predicate_result_type<decltype(instance)>>
+                {
+                    f(instance, executor);
+                };
+            }
+
+            template<typename T_func>
+            constexpr decltype(auto) detailed(T_func&& func) noexcept
+            {
+                return detailed_instance([f = std::forward<T_func>(func)](auto& instance, auto& executor) {
+                    f(instance.system(), executor);
+                });
+            }
+
+            template<typename T_func>
+            constexpr decltype(auto) for_subtasks(T_func&& func) noexcept
+            {
+                return detailed([f = std::forward<T_func>(func)](auto& system, auto& executor){
+                    executor.for_subtasks([&system, &f](auto& data){
+                        f(system, data);
+                    });
+                });
+            }
+        };
+    }
+
+    template<typename T_func>
+    constexpr decltype(auto) matching(T_func) noexcept
+    {
+        return __impl::predicate_holder<T_func> { };
+    }
+
+    constexpr decltype(auto) all() noexcept
+    {
+        return matching(hana::always(hana::true_c));
+    }
+
+    template<typename... T_system_tags>
+    constexpr decltype(auto) tags(T_system_tags... tags) noexcept
+    {
+        auto tag_set = hana::make_set(tags...);
+        return matching([tag_set](auto& system) {
+            auto tag = tag::system::make(system);
+            return hana::contains(tag_set, tag);
+        });
+    }
+
+}
+end_namespace_ecs_system_execution_adapter
\ No newline at end of file
diff --git a/test/dummy.cpp b/test/dummy.cpp
index 5fdbd84..8567a69 100644
--- a/test/dummy.cpp
+++ b/test/dummy.cpp
@@ -111,16 +111,21 @@ constexpr decltype(auto) settings = ::ecs::settings::make()
     .component_signatures(cs_list)
     .system_signatures   (ss_list);
 
+namespace sea = ::ecs::system_execution_adapter;
+
 TEST(DummyTest, fuu)
 {
-    std::mutex m;
     auto context = ::ecs::context::make(settings);
-    context.for_systems_dispatch([&m](auto& instance){
-        std::lock_guard l(m);
-        std::cout
-            << std::this_thread::get_id()
-            << " "
-            << type_helper<decltype(instance.system())>::name()
-            << std::endl;
+    context.step([](auto& step_proxy){
+        step_proxy.execute_systems()(
+            sea::tags(st::accelerate)
+                .for_subtasks([](auto& s, auto& data){
+                    std::cout << "accelerate" << std::endl;
+                }),
+            sea::tags(st::move)
+                .for_subtasks([](auto& s, auto& data){
+                    std::cout << "move" << std::endl;
+                })
+        );
     });
 }
\ No newline at end of file