diff --git a/Cargo.toml b/Cargo.toml
index c737fed958..763d52d4bd 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -5,7 +5,7 @@ authors = ["Carter Anderson <mcanders1@gmail.com>"]
 edition = "2018"
 
 [dependencies]
-legion = { git = "https://github.com/TomGillen/legion.git", rev = "8628b227bcbe57582fffb5e80e73c634ec4eebd9" }
+legion = { git = "https://github.com/TomGillen/legion.git", rev = "940ef3bfcb77e5d074ee3184b776ff1600da228d" }
 legion_transform = { path = "src/transform" }
 wgpu = { git = "https://github.com/gfx-rs/wgpu-rs.git", rev = "44fa1bc2fa208fa92f80944253e0da56cb7ac1fe"}
 glam = "0.8.4"
diff --git a/examples/instancing.rs b/examples/instancing.rs
index 69f81d92bb..5caa58adb5 100644
--- a/examples/instancing.rs
+++ b/examples/instancing.rs
@@ -25,10 +25,20 @@ struct Wander {
 }
 
 fn main() {
-    AppBuilder::new().add_defaults().setup(&setup).run();
+    AppBuilder::new()
+        .add_defaults()
+        .setup_world(setup)
+        .setup_systems(|builder| {
+            builder
+                .add_system(build_wander_system())
+                .add_system(build_navigate_system())
+                .add_system(build_move_system())
+                .add_system(build_print_status_system())
+        })
+        .run();
 }
 
-fn setup(world: &mut World, scheduler: &mut SystemScheduler<AppStage>) {
+fn setup(world: &mut World) {
     let cube = Mesh::load(MeshType::Cube);
     let cube_handle = {
         let mut mesh_storage = world
@@ -38,13 +48,6 @@ fn setup(world: &mut World, scheduler: &mut SystemScheduler<AppStage>) {
         mesh_storage.add(cube, "cube")
     };
 
-    let transform_system_bundle = transform_system_bundle::build(world);
-    scheduler.add_systems(AppStage::Update, transform_system_bundle);
-    scheduler.add_system(AppStage::Update, build_wander_system());
-    scheduler.add_system(AppStage::Update, build_navigate_system());
-    scheduler.add_system(AppStage::Update, build_move_system());
-    scheduler.add_system(AppStage::Update, build_print_status_system());
-
     world.insert(
         (),
         vec![
@@ -112,7 +115,7 @@ fn build_wander_system() -> Box<dyn Schedulable> {
             Write<NavigationPoint>,
         )>::query())
         .build(move |_, world, time, person_query| {
-            for (_, translation, mut wander, mut navigation_point) in person_query.iter(world) {
+            for (_, translation, mut wander, mut navigation_point) in person_query.iter_mut(world) {
                 wander.elapsed += time.delta_seconds;
                 if wander.elapsed >= wander.duration {
                     let direction = math::vec3(
@@ -141,7 +144,7 @@ fn build_navigate_system() -> Box<dyn Schedulable> {
             Write<NavigationPoint>,
         )>::query())
         .build(move |_, world, _, person_query| {
-            for (_, translation, mut velocity, navigation_point) in person_query.iter(world) {
+            for (_, translation, mut velocity, navigation_point) in person_query.iter_mut(world) {
                 let distance = navigation_point.target - translation.0;
                 if distance.length() > 0.01 {
                     let direction = distance.normalize();
@@ -158,7 +161,7 @@ fn build_move_system() -> Box<dyn Schedulable> {
         .read_resource::<Time>()
         .with_query(<(Write<Translation>, Read<Velocity>)>::query())
         .build(move |_, world, time, person_query| {
-            for (mut translation, velocity) in person_query.iter(world) {
+            for (mut translation, velocity) in person_query.iter_mut(world) {
                 translation.0 += velocity.value * time.delta_seconds;
             }
         })
diff --git a/examples/parenting.rs b/examples/parenting.rs
index 12d7fb7f59..5d7fceac3d 100644
--- a/examples/parenting.rs
+++ b/examples/parenting.rs
@@ -8,7 +8,11 @@ use bevy::{
 struct Rotator;
 
 fn main() {
-    AppBuilder::new().add_defaults().setup(&setup).run();
+    AppBuilder::new()
+        .add_defaults()
+        .setup_world(setup)
+        .setup_systems(|builder: Builder| builder.add_system(build_rotator_system()))
+        .run();
 }
 
 fn build_rotator_system() -> Box<dyn Schedulable> {
@@ -16,13 +20,13 @@ fn build_rotator_system() -> Box<dyn Schedulable> {
         .read_resource::<Time>()
         .with_query(<(Write<Rotator>, Write<Rotation>)>::query())
         .build(move |_, world, time, light_query| {
-            for (_, mut rotation) in light_query.iter(world) {
+            for (_, mut rotation) in light_query.iter_mut(world) {
                 rotation.0 = rotation.0 * Quat::from_rotation_x(3.0 * time.delta_seconds);
             }
         })
 }
 
-fn setup(world: &mut World, scheduler: &mut SystemScheduler<AppStage>) {
+fn setup(world: &mut World) {
     let cube = Mesh::load(MeshType::Cube);
     let plane = Mesh::load(MeshType::Plane { size: 10.0 });
 
@@ -37,10 +41,6 @@ fn setup(world: &mut World, scheduler: &mut SystemScheduler<AppStage>) {
         )
     };
 
-    let transform_system_bundle = transform_system_bundle::build(world);
-    scheduler.add_systems(AppStage::Update, transform_system_bundle);
-    scheduler.add_system(AppStage::Update, build_rotator_system());
-
     // plane
     world.insert(
         (),
diff --git a/examples/simple.rs b/examples/simple.rs
index e64d8d2469..7fdf163dcb 100644
--- a/examples/simple.rs
+++ b/examples/simple.rs
@@ -6,10 +6,10 @@ use bevy::{
 };
 
 fn main() {
-    AppBuilder::new().add_defaults().setup(&setup).run();
+    AppBuilder::new().add_defaults().setup_world(setup).run();
 }
 
-fn setup(world: &mut World, scheduler: &mut SystemScheduler<AppStage>) {
+fn setup(world: &mut World) {
     let cube = Mesh::load(MeshType::Cube);
     let plane = Mesh::load(MeshType::Plane { size: 10.0 });
 
@@ -24,9 +24,6 @@ fn setup(world: &mut World, scheduler: &mut SystemScheduler<AppStage>) {
         )
     };
 
-    let transform_system_bundle = transform_system_bundle::build(world);
-    scheduler.add_systems(AppStage::Update, transform_system_bundle);
-
     // plane
     world.insert(
         (),
diff --git a/examples/ui.rs b/examples/ui.rs
index 80ec4e50de..a3ec81dde6 100644
--- a/examples/ui.rs
+++ b/examples/ui.rs
@@ -6,10 +6,10 @@ use bevy::{
 };
 
 fn main() {
-    AppBuilder::new().add_defaults().setup(&setup).run();
+    AppBuilder::new().add_defaults().setup_world(setup).run();
 }
 
-fn setup(world: &mut World, scheduler: &mut SystemScheduler<AppStage>) {
+fn setup(world: &mut World) {
     let cube = Mesh::load(MeshType::Cube);
     let cube_handle = {
         let mut mesh_storage = world
@@ -19,9 +19,6 @@ fn setup(world: &mut World, scheduler: &mut SystemScheduler<AppStage>) {
         mesh_storage.add(cube, "cube")
     };
 
-    let transform_system_bundle = transform_system_bundle::build(world);
-    scheduler.add_systems(AppStage::Update, transform_system_bundle);
-
     world.insert(
         (),
         vec![(
diff --git a/src/app/app_builder.rs b/src/app/app_builder.rs
index 2605e84d9f..4dbac71bf7 100644
--- a/src/app/app_builder.rs
+++ b/src/app/app_builder.rs
@@ -1,48 +1,58 @@
 use crate::{
     asset::AssetStorage,
-    legion::prelude::{SystemScheduler, World},
+    legion::{
+        prelude::{Schedule, World},
+        schedule::Builder,
+    },
     render::{passes::*, *},
-    App, AppStage, Time,
+    transform_system_bundle, App, Time,
 };
 
 pub struct AppBuilder {
-    pub app: App,
+    pub world: World,
+    pub schedule_builder: Builder,
+    pub render_graph: RenderGraph,
 }
 
 impl AppBuilder {
     pub fn new() -> Self {
-        let world = World::new();
-        let scheduler = SystemScheduler::<AppStage>::new();
         AppBuilder {
-            app: App::new(world, scheduler),
+            world: World::new(),
+            schedule_builder: Schedule::builder(),
+            render_graph: RenderGraph::new(),
         }
     }
 
     pub fn build(self) -> App {
-        self.app
+        App::new(self.world, self.schedule_builder.build(), self.render_graph)
     }
 
     pub fn run(self) {
-        self.app.run();
+        self.build().run();
     }
 
     pub fn with_world(mut self, world: World) -> Self {
-        self.app.world = world;
+        self.world = world;
         self
     }
 
-    pub fn with_scheduler(mut self, scheduler: SystemScheduler<AppStage>) -> Self {
-        self.app.scheduler = scheduler;
+    pub fn with_schedule(mut self, schedule_builder: Builder) -> Self {
+        self.schedule_builder = schedule_builder;
         self
     }
 
-    pub fn setup(mut self, setup: &dyn Fn(&mut World, &mut SystemScheduler<AppStage>)) -> Self {
-        setup(&mut self.app.world, &mut self.app.scheduler);
+    pub fn setup_world(mut self, setup: impl Fn(&mut World)) -> Self {
+        setup(&mut self.world);
+        self
+    }
+
+    pub fn setup_systems(mut self, setup: impl Fn(Builder) -> Builder) -> Self {
+        self.schedule_builder = setup(self.schedule_builder);
         self
     }
 
     pub fn add_default_passes(mut self) -> Self {
-        let render_graph = &mut self.app.render_graph;
+        let render_graph = &mut self.render_graph;
         render_graph
             .add_render_resource_manager(Box::new(render_resources::MaterialResourceManager));
         render_graph
@@ -65,13 +75,22 @@ impl AppBuilder {
     }
 
     pub fn add_default_resources(mut self) -> Self {
-        let resources = &mut self.app.world.resources;
+        let resources = &mut self.world.resources;
         resources.insert(Time::new());
         resources.insert(AssetStorage::<Mesh, MeshType>::new());
         self
     }
 
+    pub fn add_default_systems(mut self) -> Self {
+        for transform_system in transform_system_bundle::build(&mut self.world).drain(..) {
+            self.schedule_builder = self.schedule_builder.add_system(transform_system);
+        }
+        self
+    }
+
     pub fn add_defaults(self) -> Self {
-        self.add_default_resources().add_default_passes()
+        self.add_default_resources()
+            .add_default_passes()
+            .add_default_systems()
     }
 }
diff --git a/src/app/app_stage.rs b/src/app/app_stage.rs
deleted file mode 100644
index 9eaa78ffa9..0000000000
--- a/src/app/app_stage.rs
+++ /dev/null
@@ -1,18 +0,0 @@
-use legion::schedule::Stage;
-
-#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord)]
-pub enum AppStage {
-    Update,
-    Render,
-}
-
-impl Stage for AppStage {}
-
-impl std::fmt::Display for AppStage {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        match self {
-            AppStage::Update => write!(f, "update"),
-            AppStage::Render => write!(f, "draw"),
-        }
-    }
-}
diff --git a/src/app/mod.rs b/src/app/mod.rs
index 6d9de5329d..50cf4afe04 100644
--- a/src/app/mod.rs
+++ b/src/app/mod.rs
@@ -1,8 +1,6 @@
 mod app_builder;
-mod app_stage;
 
 pub use app_builder::AppBuilder;
-pub use app_stage::AppStage;
 
 use winit::{
     event,
@@ -20,15 +18,15 @@ pub struct App {
     pub window: Option<Window>,
     pub render_graph: RenderGraph,
     pub swap_chain: Option<wgpu::SwapChain>,
-    pub scheduler: SystemScheduler<AppStage>,
+    pub scheduler: Schedule,
 }
 
 impl App {
-    pub fn new(world: World, scheduler: SystemScheduler<AppStage>) -> App {
+    pub fn new(world: World, schedule: Schedule, render_graph: RenderGraph) -> App {
         App {
             world: world,
-            scheduler: scheduler,
-            render_graph: RenderGraph::new(),
+            scheduler: schedule,
+            render_graph: render_graph,
             swap_chain: None,
             window: None,
         }
diff --git a/src/lib.rs b/src/lib.rs
index aadffe9aa9..1f5a57d28a 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -5,12 +5,12 @@ pub mod render;
 mod vertex;
 
 pub use crate::core::*;
-pub use app::{App, AppBuilder, AppStage};
+pub use app::{App, AppBuilder};
 
 pub use glam as math;
 pub use legion;
 pub use legion::prelude::*;
-pub use legion::schedule::Schedulable;
+pub use legion::schedule::{Schedulable, Builder};
 pub use legion_transform;
 pub use legion_transform::prelude::*;
 pub use legion_transform::transform_system_bundle;
diff --git a/src/render/passes/forward/forward_pipeline.rs b/src/render/passes/forward/forward_pipeline.rs
index 3d903d16b1..c5c2fa2154 100644
--- a/src/render/passes/forward/forward_pipeline.rs
+++ b/src/render/passes/forward/forward_pipeline.rs
@@ -140,9 +140,9 @@ impl Pipeline for ForwardPipeline {
             .get_mut::<AssetStorage<Mesh, MeshType>>()
             .unwrap();
         let mut last_mesh_id = None;
-        let mut mesh_query =
+        let mesh_query =
             <(Read<Material>, Read<Handle<Mesh>>)>::query().filter(!component::<Instanced>());
-        for (material, mesh) in mesh_query.iter_immutable(world) {
+        for (material, mesh) in mesh_query.iter(world) {
             let current_mesh_id = *mesh.id.read().unwrap();
 
             let mut should_load_mesh = last_mesh_id == None;
diff --git a/src/render/passes/forward_instanced/mod.rs b/src/render/passes/forward_instanced/mod.rs
index c83a563261..a012f39374 100644
--- a/src/render/passes/forward_instanced/mod.rs
+++ b/src/render/passes/forward_instanced/mod.rs
@@ -27,13 +27,13 @@ impl ForwardInstancedPipeline {
     }
 
     fn create_instance_buffer_infos(device: &Device, world: &World) -> Vec<InstanceBufferInfo> {
-        let mut entities = <(
+        let entities = <(
             Read<Material>,
             Read<LocalToWorld>,
             Read<Handle<Mesh>>,
             Read<Instanced>,
         )>::query();
-        let entities_count = entities.iter_immutable(world).count();
+        let entities_count = entities.iter(world).count();
         if entities_count == 0 {
             return Vec::new();
         }
@@ -50,7 +50,7 @@ impl ForwardInstancedPipeline {
 
         let mut last_mesh_id = None;
         for ((material, transform, mesh, _), slot) in entities
-            .iter_immutable(world)
+            .iter(world)
             .zip(temp_buf_data.data.chunks_exact_mut(size))
         {
             last_mesh_id = Some(*mesh.id.read().unwrap());
@@ -79,17 +79,17 @@ impl ForwardInstancedPipeline {
         device: &Device,
         world: &World,
     ) -> Vec<InstanceBufferInfo> {
-        let mut entities = <(
+        let entities = <(
             Read<Material>,
             Read<LocalToWorld>,
             Read<Handle<Mesh>>,
             Read<Instanced>,
         )>::query();
-        let entities_count = entities.iter_immutable(world).count();
+        let entities_count = entities.iter(world).count();
 
         let mut last_mesh_id = None;
         let mut data = Vec::with_capacity(entities_count);
-        for (material, transform, mesh, _) in entities.iter_immutable(world) {
+        for (material, transform, mesh, _) in entities.iter(world) {
             last_mesh_id = Some(*mesh.id.read().unwrap());
             let (_, _, translation) = transform.0.to_scale_rotation_translation();
 
diff --git a/src/render/passes/forward_shadow/mod.rs b/src/render/passes/forward_shadow/mod.rs
index 77f367c88b..3679855a2d 100644
--- a/src/render/passes/forward_shadow/mod.rs
+++ b/src/render/passes/forward_shadow/mod.rs
@@ -166,14 +166,14 @@ impl Pipeline for ForwardShadowPassNew {
         _swap_chain_output: &SwapChainOutput,
         world: &mut World,
     ) {
-        let mut mesh_query = <(Read<Material>, Read<Handle<Mesh>>)>::query();
+        let mesh_query = <(Read<Material>, Read<Handle<Mesh>>)>::query();
         pass.set_bind_group(0, self.bind_group.as_ref().unwrap(), &[]);
 
         let mut mesh_storage = world
             .resources
             .get_mut::<AssetStorage<Mesh, MeshType>>()
             .unwrap();
-        for (material, mesh) in mesh_query.iter_immutable(world) {
+        for (material, mesh) in mesh_query.iter(world) {
             if let Some(mesh_asset) = mesh_storage.get(*mesh.id.read().unwrap()) {
                 mesh_asset.setup_buffers(&render_graph.device);
                 pass.set_bind_group(1, material.bind_group.as_ref().unwrap(), &[]);
diff --git a/src/render/passes/shadow/shadow_pass.rs b/src/render/passes/shadow/shadow_pass.rs
index e2bd339d69..e5d546e15b 100644
--- a/src/render/passes/shadow/shadow_pass.rs
+++ b/src/render/passes/shadow/shadow_pass.rs
@@ -57,9 +57,9 @@ impl Pass for ShadowPass {
             self.light_index = 0;
         }
 
-        let mut light_query = <(Write<Light>, Read<LocalToWorld>, Read<Translation>)>::query();
-        let light_count = light_query.iter(world).count();
-        for (i, (mut light, _, _)) in light_query.iter(world).enumerate() {
+        let light_query = <(Write<Light>, Read<LocalToWorld>, Read<Translation>)>::query();
+        let light_count = light_query.iter_mut(world).count();
+        for (i, (mut light, _, _)) in light_query.iter_mut(world).enumerate() {
             if i != self.light_index as usize {
                 continue;
             }
diff --git a/src/render/passes/shadow/shadow_pipeline.rs b/src/render/passes/shadow/shadow_pipeline.rs
index 61bc376059..17fc2e0acb 100644
--- a/src/render/passes/shadow/shadow_pipeline.rs
+++ b/src/render/passes/shadow/shadow_pipeline.rs
@@ -153,7 +153,7 @@ impl Pipeline for ShadowPipeline {
         _: &SwapChainOutput,
         world: &mut World,
     ) {
-        let mut mesh_query =
+        let mesh_query =
             <(Read<Material>, Read<Handle<Mesh>>)>::query().filter(!component::<Instanced>());
         pass.set_bind_group(0, self.bind_group.as_ref().unwrap(), &[]);
 
@@ -161,7 +161,7 @@ impl Pipeline for ShadowPipeline {
             .resources
             .get_mut::<AssetStorage<Mesh, MeshType>>()
             .unwrap();
-        for (material, mesh) in mesh_query.iter_immutable(world) {
+        for (material, mesh) in mesh_query.iter(world) {
             if let Some(mesh_asset) = mesh_storage.get(*mesh.id.read().unwrap()) {
                 mesh_asset.setup_buffers(&render_graph.device);
 
diff --git a/src/render/passes/ui/mod.rs b/src/render/passes/ui/mod.rs
index 4a13d53327..26319aca0f 100644
--- a/src/render/passes/ui/mod.rs
+++ b/src/render/passes/ui/mod.rs
@@ -39,8 +39,8 @@ impl UiPipeline {
         device: &wgpu::Device,
         world: &World,
     ) -> Vec<InstanceBufferInfo> {
-        let mut rect_query = <Read<Rect>>::query();
-        let rect_count = rect_query.iter_immutable(world).count();
+        let rect_query = <Read<Rect>>::query();
+        let rect_count = rect_query.iter(world).count();
 
         if rect_count == 0 {
             return Vec::new();
@@ -49,7 +49,7 @@ impl UiPipeline {
         let mut data = Vec::with_capacity(rect_count);
         // TODO: this probably isn't the best way to handle z-ordering
         let mut z = 0.9999;
-        for rect in rect_query.iter_immutable(world) {
+        for rect in rect_query.iter(world) {
             data.push(RectData {
                 position: rect.position.into(),
                 dimensions: rect.dimensions.into(),
diff --git a/src/render/render_resources/global_2d_resource_manager.rs b/src/render/render_resources/global_2d_resource_manager.rs
index 0ded3a101c..913b82d68d 100644
--- a/src/render/render_resources/global_2d_resource_manager.rs
+++ b/src/render/render_resources/global_2d_resource_manager.rs
@@ -47,7 +47,7 @@ impl RenderResourceManager for Global2dResourceManager {
         encoder: &'a mut wgpu::CommandEncoder,
         world: &mut World,
     ) {
-        for (mut camera, _) in <(Write<Camera>, Read<ActiveCamera2d>)>::query().iter(world) {
+        for (mut camera, _) in <(Write<Camera>, Read<ActiveCamera2d>)>::query().iter_mut(world) {
             camera.update(
                 render_graph.swap_chain_descriptor.width,
                 render_graph.swap_chain_descriptor.height,
diff --git a/src/render/render_resources/global_resource_manager.rs b/src/render/render_resources/global_resource_manager.rs
index 9cd2e28768..7668e03a72 100644
--- a/src/render/render_resources/global_resource_manager.rs
+++ b/src/render/render_resources/global_resource_manager.rs
@@ -10,7 +10,7 @@ pub struct GlobalResourceManager;
 
 impl RenderResourceManager for GlobalResourceManager {
     fn initialize(&self, render_graph: &mut RenderGraphData, world: &mut World) {
-        let light_count = <Read<Light>>::query().iter_immutable(world).count();
+        let light_count = <Read<Light>>::query().iter(world).count();
         let forward_uniforms = ForwardUniforms {
             proj: math::Mat4::identity().to_cols_array_2d(),
             num_lights: [light_count as u32, 0, 0, 0],
@@ -42,7 +42,7 @@ impl RenderResourceManager for GlobalResourceManager {
         world: &mut World,
     ) {
         for (mut camera, local_to_world, _) in
-            <(Write<Camera>, Read<LocalToWorld>, Read<ActiveCamera>)>::query().iter(world)
+            <(Write<Camera>, Read<LocalToWorld>, Read<ActiveCamera>)>::query().iter_mut(world)
         {
             camera.update(
                 render_graph.swap_chain_descriptor.width,
diff --git a/src/render/render_resources/light_resource_manager.rs b/src/render/render_resources/light_resource_manager.rs
index 0864ee975c..7bbbd59b7f 100644
--- a/src/render/render_resources/light_resource_manager.rs
+++ b/src/render/render_resources/light_resource_manager.rs
@@ -44,7 +44,7 @@ impl RenderResourceManager for LightResourceManager {
         world: &mut World,
     ) {
         if self.lights_are_dirty {
-            let mut light_query = <(Read<Light>, Read<LocalToWorld>, Read<Translation>)>::query();
+            let light_query = <(Read<Light>, Read<LocalToWorld>, Read<Translation>)>::query();
             let light_count = light_query.iter(world).count();
 
             if light_count == 0 {
diff --git a/src/render/render_resources/material_resource_manager.rs b/src/render/render_resources/material_resource_manager.rs
index 5adb50fa4d..261b7c4a2b 100644
--- a/src/render/render_resources/material_resource_manager.rs
+++ b/src/render/render_resources/material_resource_manager.rs
@@ -31,9 +31,9 @@ impl RenderResourceManager for MaterialResourceManager {
         encoder: &'a mut wgpu::CommandEncoder,
         world: &mut World,
     ) {
-        let mut entities =
+        let entities =
             <(Write<Material>, Read<LocalToWorld>)>::query().filter(!component::<Instanced>());
-        let entities_count = entities.iter(world).count();
+        let entities_count = entities.iter_mut(world).count();
         if entities_count == 0 {
             return;
         }
@@ -44,7 +44,7 @@ impl RenderResourceManager for MaterialResourceManager {
             .create_buffer_mapped(entities_count * size, wgpu::BufferUsage::COPY_SRC);
 
         for ((material, transform), slot) in entities
-            .iter(world)
+            .iter_mut(world)
             .zip(temp_buf_data.data.chunks_exact_mut(size))
         {
             slot.copy_from_slice(
@@ -62,7 +62,7 @@ impl RenderResourceManager for MaterialResourceManager {
 
         for mut material in <Write<Material>>::query()
             .filter(!component::<Instanced>())
-            .iter(world)
+            .iter_mut(world)
         {
             if let None = material.bind_group {
                 let material_uniform_size =
@@ -92,7 +92,7 @@ impl RenderResourceManager for MaterialResourceManager {
         }
 
         let temp_buf = temp_buf_data.finish();
-        for (i, (material, _)) in entities.iter(world).enumerate() {
+        for (i, (material, _)) in entities.iter_mut(world).enumerate() {
             encoder.copy_buffer_to_buffer(
                 &temp_buf,
                 (i * size) as wgpu::BufferAddress,
diff --git a/src/transform/Cargo.toml b/src/transform/Cargo.toml
index baf1b33739..3a8b24bdbd 100644
--- a/src/transform/Cargo.toml
+++ b/src/transform/Cargo.toml
@@ -7,7 +7,7 @@ edition = "2018"
 license = "MIT"
 
 [dependencies]
-legion = { git = "https://github.com/TomGillen/legion.git", rev = "8628b227bcbe57582fffb5e80e73c634ec4eebd9" }
+legion = { git = "https://github.com/TomGillen/legion.git", rev = "940ef3bfcb77e5d074ee3184b776ff1600da228d" }
 #legion = { path = "../legion" }
 glam = "0.8.3"
 log = "0.4"
diff --git a/src/transform/src/hierarchy_maintenance_system.rs b/src/transform/src/hierarchy_maintenance_system.rs
index 7db9162699..842049a5f5 100644
--- a/src/transform/src/hierarchy_maintenance_system.rs
+++ b/src/transform/src/hierarchy_maintenance_system.rs
@@ -49,7 +49,7 @@ pub fn build(_: &mut World) -> Vec<Box<dyn Schedulable>> {
                 HashMap::<Entity, SmallVec<[Entity; 8]>>::with_capacity(16);
 
             // Entities with a changed Parent (that also have a PreviousParent, even if None)
-            for (entity, (parent, mut previous_parent)) in queries.1.iter_entities(world) {
+            for (entity, (parent, mut previous_parent)) in queries.1.iter_entities_mut(world) {
                 log::trace!("Parent changed for {}", entity);
 
                 // If the `PreviousParent` is not None.
diff --git a/src/transform/src/local_to_world_propagate_system.rs b/src/transform/src/local_to_world_propagate_system.rs
index 3865af14dd..8e2e0eeb3f 100644
--- a/src/transform/src/local_to_world_propagate_system.rs
+++ b/src/transform/src/local_to_world_propagate_system.rs
@@ -1,7 +1,7 @@
 #![allow(dead_code)]
 use crate::{
     components::*,
-    ecs::{prelude::*, system::PreparedWorld},
+    ecs::{prelude::*, system::SubWorld},
 };
 
 pub fn build(_: &mut World) -> Box<dyn Schedulable> {
@@ -22,7 +22,7 @@ pub fn build(_: &mut World) -> Box<dyn Schedulable> {
 
 fn propagate_recursive(
     parent_local_to_world: LocalToWorld,
-    world: &mut PreparedWorld,
+    world: &mut SubWorld,
     entity: Entity,
     commands: &mut CommandBuffer,
 ) {
diff --git a/src/transform/src/local_to_world_system.rs b/src/transform/src/local_to_world_system.rs
index 110a3fd819..c240fc1d68 100644
--- a/src/transform/src/local_to_world_system.rs
+++ b/src/transform/src/local_to_world_system.rs
@@ -224,7 +224,7 @@ pub fn build(_: &mut World) -> Box<dyn Schedulable> {
                 // Just to issue warnings: Scale + NonUniformScale
                 #[allow(unused_unsafe)]
                 unsafe {
-                    l.iter_entities_immutable(world).for_each(
+                    l.iter_entities(world).for_each(
                         |(entity, (mut _ltw, _scale, _non_uniform_scale))| {
                             log::warn!(
                                 "Entity {:?} has both a Scale and NonUniformScale component.",