diff --git a/packages/ecs/src/api.ts b/packages/ecs/src/api.ts
index 1bb3e41943..e5bff42272 100644
--- a/packages/ecs/src/api.ts
+++ b/packages/ecs/src/api.ts
@@ -6,6 +6,7 @@ import type {
 	IID,
 	INotify,
 	IRelease,
+	Maybe,
 	Type,
 	TypedArray,
 	UIntArray,
@@ -44,9 +45,9 @@ export interface IComponent<K extends string, VALUES, GET, SET>
 	has(id: number): boolean;
 	add(id: number, val?: SET): boolean;
 	delete(id: number): boolean;
-	get(id: number): GET | undefined;
+	get(id: number): Maybe<GET>;
 	set(i: number, val: SET): boolean;
-	getIndex(i: number): GET | undefined;
+	getIndex(i: number): Maybe<GET>;
 	setIndex(i: number, val: SET): boolean;
 	setIndexUnsafe(i: number, val: SET, notify?: boolean): void;
 
@@ -89,7 +90,7 @@ export interface GroupOpts {
 export interface ICache<T> extends IClear, IRelease {
 	keys(): Iterable<number>;
 	set(key: number, val: T): T;
-	get(key: number): T | undefined;
+	get(key: number): Maybe<T>;
 	getSet(key: number, notFound: Fn0<T>): T;
 	delete(key: number): boolean;
 }
diff --git a/packages/ecs/src/caches/null.ts b/packages/ecs/src/caches/null.ts
index c7b2385f59..02888eff49 100644
--- a/packages/ecs/src/caches/null.ts
+++ b/packages/ecs/src/caches/null.ts
@@ -1,4 +1,4 @@
-import type { Fn0 } from "@thi.ng/api";
+import type { Fn0, Maybe } from "@thi.ng/api";
 import type { ICache } from "../api.js";
 
 export class NullCache<T> implements ICache<T> {
@@ -14,7 +14,7 @@ export class NullCache<T> implements ICache<T> {
 		return val;
 	}
 
-	get(_: number): T | undefined {
+	get(_: number): Maybe<T> {
 		return;
 	}
 
diff --git a/packages/ecs/src/caches/unbounded.ts b/packages/ecs/src/caches/unbounded.ts
index 3b4b8eebdd..0c7111eb8c 100644
--- a/packages/ecs/src/caches/unbounded.ts
+++ b/packages/ecs/src/caches/unbounded.ts
@@ -1,4 +1,4 @@
-import type { Fn0 } from "@thi.ng/api";
+import type { Fn0, Maybe } from "@thi.ng/api";
 import type { ICache } from "../api.js";
 
 export class UnboundedCache<T> implements ICache<T> {
@@ -26,7 +26,7 @@ export class UnboundedCache<T> implements ICache<T> {
 		return val;
 	}
 
-	get(key: number): T | undefined {
+	get(key: number): Maybe<T> {
 		return this.index.get(key);
 	}
 
diff --git a/packages/ecs/src/components/acomponent.ts b/packages/ecs/src/components/acomponent.ts
index 8fe11ea36b..1e91eaad29 100644
--- a/packages/ecs/src/components/acomponent.ts
+++ b/packages/ecs/src/components/acomponent.ts
@@ -1,4 +1,11 @@
-import type { Event, IID, INotify, Listener, UIntArray } from "@thi.ng/api";
+import type {
+	Event,
+	IID,
+	INotify,
+	Listener,
+	Maybe,
+	UIntArray,
+} from "@thi.ng/api";
 import { INotifyMixin } from "@thi.ng/api/mixins/inotify";
 import { isFunction } from "@thi.ng/checks/is-function";
 import type { IMemPoolArray } from "@thi.ng/malloc";
@@ -52,9 +59,9 @@ export abstract class AComponent<K extends string, VALUES, GET, SET>
 		return i < this.n && this.dense[i] === id;
 	}
 
-	abstract get(id: number): GET | undefined;
+	abstract get(id: number): Maybe<GET>;
 
-	abstract getIndex(i: number): GET | undefined;
+	abstract getIndex(i: number): Maybe<GET>;
 
 	valueIndexForID(id: number) {
 		const i = this.sparse[id];
diff --git a/packages/ecs/src/ecs.ts b/packages/ecs/src/ecs.ts
index c223a697bf..2831ca3c64 100644
--- a/packages/ecs/src/ecs.ts
+++ b/packages/ecs/src/ecs.ts
@@ -1,4 +1,4 @@
-import type { Event, INotify, Listener } from "@thi.ng/api";
+import type { Event, INotify, Listener, Maybe } from "@thi.ng/api";
 import { INotifyMixin } from "@thi.ng/api/mixins/inotify";
 import { uintTypeForSize } from "@thi.ng/api/typedarray";
 import { bitSize } from "@thi.ng/binary/count";
@@ -70,10 +70,10 @@ export class ECS<SPEC> implements INotify<ECSEventType> {
 
 	defComponent<K extends ComponentID<SPEC>>(
 		opts: MemMappedComponentOpts<K>
-	): MemMappedComponent<K> | undefined;
+	): Maybe<MemMappedComponent<K>>;
 	defComponent<K extends ComponentID<SPEC>>(
 		opts: ObjectComponentOpts<K, SPEC[K]>
-	): ObjectComponent<K, SPEC[K]> | undefined;
+	): Maybe<ObjectComponent<K, SPEC[K]>>;
 	defComponent<K extends ComponentID<SPEC>>(opts: any) {
 		assert(
 			!this.components.has(opts.id),