diff --git a/CHANGELOG.md b/CHANGELOG.md
index a74798867b..245ebf4326 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,8 +2,11 @@
 
 ## master
 
+- **Important** The `ClassOf` alias for `createClass` has been removed, us `createClass` (with new generics) directly
+
 Changes:
 
+- `createType<T = Codec>('...': K)` now returns `Codec` when `K` is not in the InterfaceRegistry, with `T` override
 - Handle `BitSequence` in `PortableRegistry`
 - Move all static test support files into `@polkadot/types-support`
 - Align static Metadata with latest Substrate, Polkadot & Kusama
diff --git a/packages/api-derive/src/democracy/dispatchQueue.ts b/packages/api-derive/src/democracy/dispatchQueue.ts
index a3e29ab316..30fa29a978 100644
--- a/packages/api-derive/src/democracy/dispatchQueue.ts
+++ b/packages/api-derive/src/democracy/dispatchQueue.ts
@@ -86,7 +86,7 @@ function queryScheduler (api: ApiInterfaceRx): Observable<DeriveDispatch[]> {
               const id = scheduled.maybeId.unwrap().toHex();
 
               if (id.startsWith(DEMOCRACY_ID)) {
-                const [, index] = api.registry.createType('(u64, ReferendumIndex)' as any, id) as ITuple<[u64, ReferendumIndex]>;
+                const [, index] = api.registry.createType<ITuple<[u64, ReferendumIndex]>>('(u64, ReferendumIndex)', id);
                 const imageHash = scheduled.call.args[0] as Hash;
 
                 result.push({ at, imageHash, index });
diff --git a/packages/api-derive/src/index.spec.ts b/packages/api-derive/src/index.spec.ts
index 5d03f82fc3..c6463768fa 100644
--- a/packages/api-derive/src/index.spec.ts
+++ b/packages/api-derive/src/index.spec.ts
@@ -14,10 +14,7 @@ import { TypeRegistry } from '@polkadot/types/create';
 import { ExactDerive } from '.';
 
 const testFunction = (api: ApiRx): any => {
-  return <
-    Section extends keyof ExactDerive,
-    Method extends keyof (typeof api.derive[Section])
-  >(section: Section, method: Method, inputs: any[]): void => {
+  return <S extends keyof ExactDerive, M extends keyof (typeof api.derive[S])>(section: S, method: M, inputs: any[]): void => {
     describe(`derive.${section}.${method}`, (): void => {
       it('should be a function', (): void => {
         expect(typeof api.derive[section][method]).toBe('function');
@@ -96,7 +93,7 @@ describe('derive', (): void => {
     testFunction(api)('balances', 'fees', ['a', 'b']);
 
     // new
-    testFunction(api)('custom' as any, 'test', [1, 2, 3]);
+    testFunction(api)('custom', 'test', [1, 2, 3]);
 
     // existing
     testFunction(api)('chain', 'bestNumber', []);
diff --git a/packages/typegen/src/util/derived.ts b/packages/typegen/src/util/derived.ts
index 375e2c32af..48ae67b023 100644
--- a/packages/typegen/src/util/derived.ts
+++ b/packages/typegen/src/util/derived.ts
@@ -6,7 +6,7 @@ import type { Constructor, Registry } from '@polkadot/types/types';
 
 import { Compact, Enum, Option, Struct, Tuple, UInt, Vec } from '@polkadot/types/codec';
 import { AbstractInt } from '@polkadot/types/codec/AbstractInt';
-import { ClassOfUnsafe, getTypeDef } from '@polkadot/types/create';
+import { getTypeDef } from '@polkadot/types/create';
 import { TypeDefInfo } from '@polkadot/types/create/types';
 import { GenericAccountId, GenericLookupSource, GenericVote } from '@polkadot/types/generic';
 import { AllConvictions } from '@polkadot/types/interfaces/democracy/definitions';
@@ -30,7 +30,7 @@ export function getDerivedTypes (registry: Registry, definitions: Record<string,
   // `primitiveName` represents the actual primitive type our type is mapped to
   const isCompact = isCompactEncodable(
     (primitiveClasses as Record<string, any>)[primitiveName] ||
-    ClassOfUnsafe(registry, type)
+    registry.createClass(type)
   );
   const def = getTypeDef(type);
 
@@ -87,7 +87,7 @@ export function getSimilarTypes (registry: Registry, definitions: Record<string,
     return ['null'];
   }
 
-  const Clazz = ClassOfUnsafe(registry, type);
+  const Clazz = registry.createClass(type);
 
   if (isChildClass(Vec, Clazz)) {
     const vecDef = getTypeDef(type);
diff --git a/packages/types/src/checkTypes.manual.ts b/packages/types/src/checkTypes.manual.ts
new file mode 100644
index 0000000000..01398cfbc6
--- /dev/null
+++ b/packages/types/src/checkTypes.manual.ts
@@ -0,0 +1,33 @@
+// Copyright 2017-2021 @polkadot/types authors & contributors
+// SPDX-License-Identifier: Apache-2.0
+
+import type { u32 } from './primitive';
+import type { Registry } from './types/registry';
+
+import { assert } from '@polkadot/util';
+
+import { TypeRegistry } from './create';
+
+function registryCheck (registry: Registry): void {
+  // Should be AccountId
+  const aa = registry.createType('AccountId');
+
+  assert(aa.isAscii, 'All ok');
+
+  // Should be Codec
+  const bb = registry.createType('Something');
+
+  assert(bb.toHuman(), 'All ok');
+
+  // Should be u32
+  const cc = registry.createType('Something' as 'u32');
+
+  assert(cc.divn(123), 'All ok');
+
+  // Should be u32
+  const dd = registry.createType<u32>('Something');
+
+  assert(dd.divn(123), 'All ok');
+}
+
+registryCheck(new TypeRegistry());
diff --git a/packages/types/src/codec/BTreeMap.spec.ts b/packages/types/src/codec/BTreeMap.spec.ts
index 92e8dcec6d..1f4563f22f 100644
--- a/packages/types/src/codec/BTreeMap.spec.ts
+++ b/packages/types/src/codec/BTreeMap.spec.ts
@@ -69,7 +69,7 @@ describe('BTreeMap', (): void => {
   it('decodes within more complicated types', (): void => {
     const s = new Struct(registry, {
       placeholder: U32,
-      value: 'BTreeMap<Text, U32>' as 'u32'
+      value: 'BTreeMap<Text, U32>'
     });
 
     s.set('value', new (BTreeMap.with(Text, U32))(registry, mockU32TextMap));
diff --git a/packages/types/src/codec/BTreeMap.ts b/packages/types/src/codec/BTreeMap.ts
index 4aab90f219..0536231041 100644
--- a/packages/types/src/codec/BTreeMap.ts
+++ b/packages/types/src/codec/BTreeMap.ts
@@ -1,12 +1,12 @@
 // Copyright 2017-2021 @polkadot/types authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
-import type { Codec, Constructor, InterfaceTypes, Registry } from '../types';
+import type { Codec, Constructor, Registry } from '../types';
 
 import { CodecMap } from './Map';
 
 export class BTreeMap<K extends Codec = Codec, V extends Codec = Codec> extends CodecMap<K, V> {
-  public static with<K extends Codec, V extends Codec> (keyType: Constructor<K> | keyof InterfaceTypes, valType: Constructor<V> | keyof InterfaceTypes): Constructor<CodecMap<K, V>> {
+  public static with<K extends Codec, V extends Codec> (keyType: Constructor<K> | string, valType: Constructor<V> | string): Constructor<CodecMap<K, V>> {
     return class extends BTreeMap<K, V> {
       constructor (registry: Registry, value?: Uint8Array | string | Map<any, any>) {
         super(registry, keyType, valType, value, 'BTreeMap');
diff --git a/packages/types/src/codec/BTreeSet.ts b/packages/types/src/codec/BTreeSet.ts
index 027eebe78d..914653bd49 100644
--- a/packages/types/src/codec/BTreeSet.ts
+++ b/packages/types/src/codec/BTreeSet.ts
@@ -2,7 +2,7 @@
 // SPDX-License-Identifier: Apache-2.0
 
 import type { CodecHash, Hash } from '../interfaces/runtime';
-import type { AnyJson, Codec, Constructor, InterfaceTypes, Registry } from '../types';
+import type { AnyJson, Codec, Constructor, Registry } from '../types';
 
 import { compactFromU8a, compactToU8a, isHex, isU8a, logger, stringify, u8aConcat, u8aToHex, u8aToU8a } from '@polkadot/util';
 
@@ -60,7 +60,7 @@ function decodeSetFromSet<V extends Codec = Codec> (registry: Registry, ValClass
  * @param jsonSet
  * @internal
  */
-function decodeSet<V extends Codec = Codec> (registry: Registry, valType: Constructor<V> | keyof InterfaceTypes, value?: Uint8Array | string | string[] | Set<any>): Set<V> {
+function decodeSet<V extends Codec = Codec> (registry: Registry, valType: Constructor<V> | string, value?: Uint8Array | string | string[] | Set<any>): Set<V> {
   if (!value) {
     return new Set<V>();
   }
@@ -83,14 +83,14 @@ export class BTreeSet<V extends Codec = Codec> extends Set<V> implements Codec {
 
   readonly #ValClass: Constructor<V>;
 
-  constructor (registry: Registry, valType: Constructor<V> | keyof InterfaceTypes, rawValue?: Uint8Array | string | string[] | Set<any>) {
+  constructor (registry: Registry, valType: Constructor<V> | string, rawValue?: Uint8Array | string | string[] | Set<any>) {
     super(sortSet(decodeSet(registry, valType, rawValue)));
 
     this.registry = registry;
     this.#ValClass = typeToConstructor(registry, valType);
   }
 
-  public static with<V extends Codec> (valType: Constructor<V> | keyof InterfaceTypes): Constructor<BTreeSet<V>> {
+  public static with<V extends Codec> (valType: Constructor<V> | string): Constructor<BTreeSet<V>> {
     return class extends BTreeSet<V> {
       constructor (registry: Registry, value?: Uint8Array | string | Set<any>) {
         super(registry, valType, value);
diff --git a/packages/types/src/codec/Compact.ts b/packages/types/src/codec/Compact.ts
index 4f04145758..fc1a22c7a7 100644
--- a/packages/types/src/codec/Compact.ts
+++ b/packages/types/src/codec/Compact.ts
@@ -3,7 +3,7 @@
 
 import type { BN } from '@polkadot/util';
 import type { CodecHash, Hash } from '../interfaces';
-import type { AnyJson, AnyNumber, Constructor, ICompact, InterfaceTypes, Registry } from '../types';
+import type { AnyJson, AnyNumber, Constructor, ICompact, Registry } from '../types';
 import type { CompactEncodable } from './types';
 
 import { compactFromU8a, compactToU8a, isBigInt, isBn, isNumber, isString } from '@polkadot/util';
@@ -27,13 +27,13 @@ export class Compact<T extends CompactEncodable> implements ICompact<T> {
 
   readonly #raw: T;
 
-  constructor (registry: Registry, Type: Constructor<T> | keyof InterfaceTypes, value: Compact<T> | AnyNumber = 0) {
+  constructor (registry: Registry, Type: Constructor<T> | string, value: Compact<T> | AnyNumber = 0) {
     this.registry = registry;
     this.#Type = typeToConstructor(registry, Type);
     this.#raw = Compact.decodeCompact<T>(registry, this.#Type, value) as T;
   }
 
-  public static with<T extends CompactEncodable> (Type: Constructor<T> | keyof InterfaceTypes): Constructor<Compact<T>> {
+  public static with<T extends CompactEncodable> (Type: Constructor<T> | string): Constructor<Compact<T>> {
     return class extends Compact<T> {
       constructor (registry: Registry, value?: Compact<T> | AnyNumber) {
         super(registry, Type, value);
diff --git a/packages/types/src/codec/Enum.ts b/packages/types/src/codec/Enum.ts
index b7194ec989..c3cfaf8dde 100644
--- a/packages/types/src/codec/Enum.ts
+++ b/packages/types/src/codec/Enum.ts
@@ -2,7 +2,7 @@
 // SPDX-License-Identifier: Apache-2.0
 
 import type { CodecHash, Hash } from '../interfaces';
-import type { AnyJson, Codec, Constructor, InterfaceTypes, Registry } from '../types';
+import type { AnyJson, Codec, Constructor, Registry } from '../types';
 
 import { assert, hexToU8a, isHex, isNumber, isObject, isString, isU8a, isUndefined, stringCamelCase, stringify, stringUpperFirst, u8aConcat, u8aToHex } from '@polkadot/util';
 
@@ -27,7 +27,7 @@ interface Decoded {
   value: Codec;
 }
 
-function isRustEnum (def: Record<string, keyof InterfaceTypes | Constructor> | Record<string, number>): def is Record<string, keyof InterfaceTypes | Constructor> {
+function isRustEnum (def: Record<string, string | Constructor> | Record<string, number>): def is Record<string, string | Constructor> {
   const defValues = Object.values(def);
 
   if (defValues.some((v) => isNumber(v))) {
@@ -39,7 +39,7 @@ function isRustEnum (def: Record<string, keyof InterfaceTypes | Constructor> | R
   return true;
 }
 
-function extractDef (registry: Registry, _def: Record<string, keyof InterfaceTypes | Constructor> | Record<string, number> | string[]): { def: TypesDef; isBasic: boolean; isIndexed: boolean } {
+function extractDef (registry: Registry, _def: Record<string, string | Constructor> | Record<string, number> | string[]): { def: TypesDef; isBasic: boolean; isIndexed: boolean } {
   if (Array.isArray(_def)) {
     return {
       def: _def.reduce((def: TypesDef, key, index): TypesDef => {
@@ -180,7 +180,7 @@ export class Enum implements Codec {
 
   readonly #raw: Codec;
 
-  constructor (registry: Registry, def: Record<string, keyof InterfaceTypes | Constructor> | Record<string, number> | string[], value?: unknown, index?: number) {
+  constructor (registry: Registry, def: Record<string, string | Constructor> | Record<string, number> | string[], value?: unknown, index?: number) {
     const defInfo = extractDef(registry, def);
     const decoded = decodeEnum(registry, defInfo.def, value, index);
 
@@ -193,7 +193,7 @@ export class Enum implements Codec {
     this.#raw = decoded.value;
   }
 
-  public static with (Types: Record<string, keyof InterfaceTypes | Constructor> | Record<string, number> | string[]): EnumConstructor<Enum> {
+  public static with (Types: Record<string, string | Constructor> | Record<string, number> | string[]): EnumConstructor<Enum> {
     return class extends Enum {
       constructor (registry: Registry, value?: unknown, index?: number) {
         super(registry, Types, value, index);
diff --git a/packages/types/src/codec/HashMap.ts b/packages/types/src/codec/HashMap.ts
index 9002d62037..7dec233fa8 100644
--- a/packages/types/src/codec/HashMap.ts
+++ b/packages/types/src/codec/HashMap.ts
@@ -1,12 +1,12 @@
 // Copyright 2017-2021 @polkadot/types authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
-import type { Codec, Constructor, InterfaceTypes, Registry } from '../types';
+import type { Codec, Constructor, Registry } from '../types';
 
 import { CodecMap } from './Map';
 
 export class HashMap<K extends Codec = Codec, V extends Codec = Codec> extends CodecMap<K, V> {
-  public static with<K extends Codec, V extends Codec> (keyType: Constructor<K> | keyof InterfaceTypes, valType: Constructor<V> | keyof InterfaceTypes): Constructor<CodecMap<K, V>> {
+  public static with<K extends Codec, V extends Codec> (keyType: Constructor<K> | string, valType: Constructor<V> | string): Constructor<CodecMap<K, V>> {
     return class extends HashMap<K, V> {
       constructor (registry: Registry, value?: Uint8Array | string | Map<any, any>) {
         super(registry, keyType, valType, value);
diff --git a/packages/types/src/codec/Linkage.spec.ts b/packages/types/src/codec/Linkage.spec.ts
index ad7aee10dc..3bf66ca70e 100644
--- a/packages/types/src/codec/Linkage.spec.ts
+++ b/packages/types/src/codec/Linkage.spec.ts
@@ -25,7 +25,7 @@ describe('Linkage', (): void => {
     ).toEqual(LINKA);
     expect(
       registry.createType(
-        'Linkage<AccountId>' as 'u32',
+        'Linkage<AccountId>',
         '0x0001da30b68f54f686f586ddb29de12b682dd8bd1404566fb8a8db5dec20aa5b6b36'
       ).toHuman()
     ).toEqual(LINKA);
@@ -33,7 +33,7 @@ describe('Linkage', (): void => {
     // actual check
     expect(
       registry.createType(
-        '(ValidatorPrefsWithCommission, Linkage<AccountId>)' as 'u32',
+        '(ValidatorPrefsWithCommission, Linkage<AccountId>)',
         '0x0284d7170001da30b68f54f686f586ddb29de12b682dd8bd1404566fb8a8db5dec20aa5b6b36'
       ).toHuman()
     ).toEqual([PREFS, LINKA]);
diff --git a/packages/types/src/codec/Linkage.ts b/packages/types/src/codec/Linkage.ts
index b93801ce29..8724cfc77c 100644
--- a/packages/types/src/codec/Linkage.ts
+++ b/packages/types/src/codec/Linkage.ts
@@ -1,7 +1,7 @@
 // Copyright 2017-2021 @polkadot/types authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
-import type { Codec, Constructor, InterfaceTypes, Registry } from '../types';
+import type { Codec, Constructor, Registry } from '../types';
 
 import { Option } from './Option';
 import { Struct } from './Struct';
@@ -17,7 +17,7 @@ const EMPTY = new Uint8Array();
  * @description The wrapper for the result from a LinkedMap
  */
 export class Linkage<T extends Codec> extends Struct {
-  constructor (registry: Registry, Type: Constructor | keyof InterfaceTypes, value?: unknown) {
+  constructor (registry: Registry, Type: Constructor | string, value?: unknown) {
     super(registry, {
       previous: Option.with(Type),
       // eslint-disable-next-line sort-keys
@@ -25,7 +25,7 @@ export class Linkage<T extends Codec> extends Struct {
     }, value as string);
   }
 
-  public static withKey<O extends Codec> (Type: Constructor | keyof InterfaceTypes): Constructor<Linkage<O>> {
+  public static withKey<O extends Codec> (Type: Constructor | string): Constructor<Linkage<O>> {
     return class extends Linkage<O> {
       constructor (registry: Registry, value?: unknown) {
         super(registry, Type, value);
diff --git a/packages/types/src/codec/Map.ts b/packages/types/src/codec/Map.ts
index 56040c5f35..a1c4424b04 100644
--- a/packages/types/src/codec/Map.ts
+++ b/packages/types/src/codec/Map.ts
@@ -2,7 +2,7 @@
 // SPDX-License-Identifier: Apache-2.0
 
 import type { CodecHash, Hash } from '../interfaces/runtime';
-import type { AnyJson, Codec, Constructor, InterfaceTypes, Registry } from '../types';
+import type { AnyJson, Codec, Constructor, Registry } from '../types';
 
 import { compactFromU8a, compactToU8a, isHex, isObject, isU8a, logger, stringify, u8aConcat, u8aToHex, u8aToU8a } from '@polkadot/util';
 
@@ -75,7 +75,7 @@ function decodeMapFromMap<K extends Codec = Codec, V extends Codec = Codec> (reg
  * @param jsonMap
  * @internal
  */
-function decodeMap<K extends Codec = Codec, V extends Codec = Codec> (registry: Registry, keyType: Constructor<K> | keyof InterfaceTypes, valType: Constructor<V> | keyof InterfaceTypes, value?: Uint8Array | string | Map<any, any>): Map<K, V> {
+function decodeMap<K extends Codec = Codec, V extends Codec = Codec> (registry: Registry, keyType: Constructor<K> | string, valType: Constructor<V> | string, value?: Uint8Array | string | Map<any, any>): Map<K, V> {
   const KeyClass = typeToConstructor(registry, keyType);
   const ValClass = typeToConstructor(registry, valType);
 
@@ -103,7 +103,7 @@ export class CodecMap<K extends Codec = Codec, V extends Codec = Codec> extends
 
   readonly #type: string;
 
-  constructor (registry: Registry, keyType: Constructor<K> | keyof InterfaceTypes, valType: Constructor<V> | keyof InterfaceTypes, rawValue: Uint8Array | string | Map<any, any> | undefined, type: 'BTreeMap' | 'HashMap' = 'HashMap') {
+  constructor (registry: Registry, keyType: Constructor<K> | string, valType: Constructor<V> | string, rawValue: Uint8Array | string | Map<any, any> | undefined, type: 'BTreeMap' | 'HashMap' = 'HashMap') {
     const decoded = decodeMap(registry, keyType, valType, rawValue);
 
     super(type === 'BTreeMap' ? sortMap(decoded) : decoded);
diff --git a/packages/types/src/codec/Option.ts b/packages/types/src/codec/Option.ts
index 24333f70e8..1faf45dcd0 100644
--- a/packages/types/src/codec/Option.ts
+++ b/packages/types/src/codec/Option.ts
@@ -2,7 +2,7 @@
 // SPDX-License-Identifier: Apache-2.0
 
 import type { CodecHash, Hash } from '../interfaces';
-import type { AnyJson, Codec, Constructor, InterfaceTypes, Registry } from '../types';
+import type { AnyJson, Codec, Constructor, Registry } from '../types';
 
 import { assert, isNull, isU8a, isUndefined, u8aToHex } from '@polkadot/util';
 
@@ -17,7 +17,7 @@ function decodeOptionU8a (registry: Registry, Type: Constructor, value: Uint8Arr
 }
 
 /** @internal */
-function decodeOption (registry: Registry, typeName: Constructor | keyof InterfaceTypes, value?: unknown): Codec {
+function decodeOption (registry: Registry, typeName: Constructor | string, value?: unknown): Codec {
   if (isNull(value) || isUndefined(value) || value instanceof Null) {
     return new Null(registry);
   }
@@ -56,13 +56,13 @@ export class Option<T extends Codec> implements Codec {
 
   readonly #raw: T;
 
-  constructor (registry: Registry, typeName: Constructor<T> | keyof InterfaceTypes, value?: unknown) {
+  constructor (registry: Registry, typeName: Constructor<T> | string, value?: unknown) {
     this.registry = registry;
     this.#Type = typeToConstructor(registry, typeName);
     this.#raw = decodeOption(registry, typeName, value) as T;
   }
 
-  public static with<O extends Codec> (Type: Constructor<O> | keyof InterfaceTypes): Constructor<Option<O>> {
+  public static with<O extends Codec> (Type: Constructor<O> | string): Constructor<Option<O>> {
     return class extends Option<O> {
       constructor (registry: Registry, value?: unknown) {
         super(registry, Type, value);
diff --git a/packages/types/src/codec/Result.ts b/packages/types/src/codec/Result.ts
index d35741b2cf..2ba5ff0ace 100644
--- a/packages/types/src/codec/Result.ts
+++ b/packages/types/src/codec/Result.ts
@@ -1,7 +1,7 @@
 // Copyright 2017-2021 @polkadot/types authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
-import type { Codec, Constructor, InterfaceTypes, Registry } from '../types';
+import type { Codec, Constructor, Registry } from '../types';
 
 import { assert } from '@polkadot/util';
 
@@ -13,13 +13,13 @@ import { Enum } from './Enum';
  * A Result maps to the Rust Result type, that can either wrap a success or error value
  */
 export class Result<O extends Codec, E extends Codec> extends Enum {
-  constructor (registry: Registry, Ok: Constructor<O> | keyof InterfaceTypes, Err: Constructor<E> | keyof InterfaceTypes, value?: unknown) {
+  constructor (registry: Registry, Ok: Constructor<O> | string, Err: Constructor<E> | string, value?: unknown) {
     // NOTE This is order-dependent, Ok (with index 0) needs to be first
     // eslint-disable-next-line sort-keys
     super(registry, { Ok, Err }, value);
   }
 
-  public static override with<O extends Codec, E extends Codec> (Types: { Ok: Constructor<O> | keyof InterfaceTypes; Err: Constructor<E> | keyof InterfaceTypes }): Constructor<Result<O, E>> {
+  public static override with<O extends Codec, E extends Codec> (Types: { Ok: Constructor<O> | string; Err: Constructor<E> | string }): Constructor<Result<O, E>> {
     return class extends Result<O, E> {
       constructor (registry: Registry, value?: unknown) {
         super(registry, Types.Ok, Types.Err, value);
diff --git a/packages/types/src/codec/Struct.ts b/packages/types/src/codec/Struct.ts
index 665c7694a4..81d630aab1 100644
--- a/packages/types/src/codec/Struct.ts
+++ b/packages/types/src/codec/Struct.ts
@@ -2,13 +2,13 @@
 // SPDX-License-Identifier: Apache-2.0
 
 import type { CodecHash, Hash } from '../interfaces/runtime';
-import type { AnyJson, BareOpts, Codec, Constructor, ConstructorDef, InterfaceTypes, Registry } from '../types';
+import type { AnyJson, BareOpts, Codec, Constructor, ConstructorDef, Registry } from '../types';
 
 import { assert, hexToU8a, isBoolean, isFunction, isHex, isObject, isU8a, isUndefined, stringCamelCase, stringify, u8aConcat, u8aToHex } from '@polkadot/util';
 
 import { compareMap, decodeU8a, mapToTypeMap } from './utils';
 
-type TypesDef<T = Codec> = Record<string, keyof InterfaceTypes | Constructor<T>>;
+type TypesDef<T = Codec> = Record<string, string | Constructor<T>>;
 
 /** @internal */
 function decodeStructFromObject <T> (registry: Registry, Types: ConstructorDef, value: any, jsonMap: Map<any, string>): T {
diff --git a/packages/types/src/codec/Tuple.spec.ts b/packages/types/src/codec/Tuple.spec.ts
index 4baa41dad1..ef1ac95b99 100644
--- a/packages/types/src/codec/Tuple.spec.ts
+++ b/packages/types/src/codec/Tuple.spec.ts
@@ -51,7 +51,7 @@ describe('Tuple', (): void => {
 
     it('decodes properly from complex types', (): void => {
       const INPUT = '0xcc0200000000';
-      const test = registry.createType('(u32, [u32; 0], u16)' as 'u32', INPUT);
+      const test = registry.createType('(u32, [u32; 0], u16)', INPUT);
 
       expect(test.encodedLength).toEqual(4 + 0 + 2);
       expect(test.toHex()).toEqual(INPUT);
diff --git a/packages/types/src/codec/Tuple.ts b/packages/types/src/codec/Tuple.ts
index b629effdbf..6c23d77eb7 100644
--- a/packages/types/src/codec/Tuple.ts
+++ b/packages/types/src/codec/Tuple.ts
@@ -1,7 +1,7 @@
 // Copyright 2017-2021 @polkadot/types authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
-import type { AnyNumber, AnyString, AnyU8a, Codec, Constructor, InterfaceTypes, Registry } from '../types';
+import type { AnyNumber, AnyString, AnyU8a, Codec, Constructor, Registry } from '../types';
 
 import { isHex, isU8a, stringify, u8aConcat, u8aToU8a } from '@polkadot/util';
 
@@ -14,8 +14,8 @@ type TupleConstructors = Constructor[] | {
   [index: string]: Constructor;
 };
 
-type TupleTypes = (Constructor | keyof InterfaceTypes)[] | {
-  [index: string]: Constructor | keyof InterfaceTypes;
+type TupleTypes = (Constructor | string)[] | {
+  [index: string]: Constructor | string;
 };
 
 /** @internal */
diff --git a/packages/types/src/codec/Vec.spec.ts b/packages/types/src/codec/Vec.spec.ts
index 40b231f2cb..d0f8bb1967 100644
--- a/packages/types/src/codec/Vec.spec.ts
+++ b/packages/types/src/codec/Vec.spec.ts
@@ -2,7 +2,7 @@
 // SPDX-License-Identifier: Apache-2.0
 
 import type { PropIndex } from '../interfaces/democracy';
-import type { Codec, CodecTo } from '../types';
+import type { Codec, CodecTo, ITuple } from '../types';
 
 import rpcMetadata from '@polkadot/types-support/metadata/static-substrate';
 import { randomAsU8a } from '@polkadot/util-crypto';
@@ -11,7 +11,7 @@ import { createTypeUnsafe, TypeRegistry } from '../create';
 import { GenericAccountId as AccountId } from '../generic';
 import { Metadata } from '../metadata';
 import { Text } from '../primitive';
-import { Tuple, Vec } from '.';
+import { Vec } from '.';
 
 const registry = new TypeRegistry();
 const metadata = new Metadata(registry, rpcMetadata);
@@ -69,20 +69,19 @@ describe('Vec', (): void => {
   });
 
   it('decodes a complex type via construction', (): void => {
-    const test = createTypeUnsafe(registry, 'Vec<(PropIndex, AccountId)>', [new Uint8Array([
+    const test = createTypeUnsafe<Vec<ITuple<[PropIndex, AccountId]>>>(registry, 'Vec<(PropIndex, AccountId)>', [new Uint8Array([
       4, 10, 0, 0, 0, 209, 114, 167, 76, 218, 76, 134, 89, 18, 195, 43, 160, 168, 10, 87, 174, 105, 171, 174, 65, 14, 92, 203, 89, 222, 232, 78, 47, 68, 50, 219, 79
     ])]);
-    const first = (test as Vec<Codec>)[0] as Tuple;
 
-    expect((first[0] as PropIndex).toNumber()).toEqual(10);
-    expect((first[1] as AccountId).toString()).toEqual('5GoKvZWG5ZPYL1WUovuHW3zJBWBP5eT8CbqjdRY4Q6iMaQua');
+    expect(test[0][0].toNumber()).toEqual(10);
+    expect(test[0][1].toString()).toEqual('5GoKvZWG5ZPYL1WUovuHW3zJBWBP5eT8CbqjdRY4Q6iMaQua');
   });
 
   it('decodes a complex type via construction', (): void => {
     const INPUT = '0x08cc0200000000ce0200000001';
-    const test = createTypeUnsafe(registry, 'Vec<(u32, [u32; 0], u16)>' as any, [INPUT]);
+    const test = createTypeUnsafe<Vec<Codec>>(registry, 'Vec<(u32, [u32; 0], u16)>', [INPUT]);
 
-    expect((test as Vec<any>).length).toEqual(2);
+    expect(test).toHaveLength(2);
     expect(test.toHex()).toEqual(INPUT);
   });
 
diff --git a/packages/types/src/codec/Vec.ts b/packages/types/src/codec/Vec.ts
index 3951486ffd..33390e3c96 100644
--- a/packages/types/src/codec/Vec.ts
+++ b/packages/types/src/codec/Vec.ts
@@ -1,7 +1,7 @@
 // Copyright 2017-2021 @polkadot/types authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
-import type { Codec, Constructor, InterfaceTypes, Registry } from '../types';
+import type { Codec, Constructor, Registry } from '../types';
 
 import { assert, compactFromU8a, logger, u8aToU8a } from '@polkadot/util';
 
@@ -22,7 +22,7 @@ const l = logger('Vec');
 export class Vec<T extends Codec> extends AbstractArray<T> {
   private _Type: Constructor<T>;
 
-  constructor (registry: Registry, Type: Constructor<T> | keyof InterfaceTypes, value: Vec<Codec> | Uint8Array | string | unknown[] = []) {
+  constructor (registry: Registry, Type: Constructor<T> | string, value: Vec<Codec> | Uint8Array | string | unknown[] = []) {
     const Clazz = typeToConstructor<T>(registry, Type);
 
     super(registry, ...Vec.decodeVec(registry, Clazz, value));
@@ -55,7 +55,7 @@ export class Vec<T extends Codec> extends AbstractArray<T> {
     return decodeU8a(registry, u8a.subarray(offset), new Array(length.toNumber()).fill(Type)) as T[];
   }
 
-  public static with<O extends Codec> (Type: Constructor<O> | keyof InterfaceTypes): Constructor<Vec<O>> {
+  public static with<O extends Codec> (Type: Constructor<O> | string): Constructor<Vec<O>> {
     return class extends Vec<O> {
       constructor (registry: Registry, value?: any[]) {
         super(registry, Type, value);
diff --git a/packages/types/src/codec/VecFixed.ts b/packages/types/src/codec/VecFixed.ts
index 679091f0ee..e59b0be4b7 100644
--- a/packages/types/src/codec/VecFixed.ts
+++ b/packages/types/src/codec/VecFixed.ts
@@ -1,7 +1,7 @@
 // Copyright 2017-2021 @polkadot/types authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
-import type { Codec, Constructor, InterfaceTypes, Registry } from '../types';
+import type { Codec, Constructor, Registry } from '../types';
 
 import { assert, compactToU8a, isHex, isU8a, u8aConcat } from '@polkadot/util';
 
@@ -36,7 +36,7 @@ function decodeVecFixed<T extends Codec> (registry: Registry, Type: Constructor<
 export class VecFixed<T extends Codec> extends AbstractArray<T> {
   private _Type: Constructor<T>;
 
-  constructor (registry: Registry, Type: Constructor<T> | keyof InterfaceTypes, length: number, value: VecFixed<any> | Uint8Array | string | any[] = [] as any[]) {
+  constructor (registry: Registry, Type: Constructor<T> | string, length: number, value: VecFixed<any> | Uint8Array | string | any[] = [] as any[]) {
     const Clazz = typeToConstructor<T>(registry, Type);
 
     super(registry, ...decodeVecFixed(registry, Clazz, length, value));
@@ -44,7 +44,7 @@ export class VecFixed<T extends Codec> extends AbstractArray<T> {
     this._Type = Clazz;
   }
 
-  public static with<O extends Codec> (Type: Constructor<O> | keyof InterfaceTypes, length: number): Constructor<VecFixed<O>> {
+  public static with<O extends Codec> (Type: Constructor<O> | string, length: number): Constructor<VecFixed<O>> {
     return class extends VecFixed<O> {
       constructor (registry: Registry, value?: any[]) {
         super(registry, Type, length, value);
diff --git a/packages/types/src/codec/utils/mapToTypeMap.ts b/packages/types/src/codec/utils/mapToTypeMap.ts
index f2166e089b..16dd1ee8dd 100644
--- a/packages/types/src/codec/utils/mapToTypeMap.ts
+++ b/packages/types/src/codec/utils/mapToTypeMap.ts
@@ -1,14 +1,14 @@
 // Copyright 2017-2021 @polkadot/types authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
-import type { Constructor, InterfaceTypes, Registry } from '../../types';
+import type { Constructor, Registry } from '../../types';
 
 import { typeToConstructor } from './typeToConstructor';
 
 /**
  * @description takes an input map of the form `{ [string]: string | Constructor }` and returns a map of `{ [string]: Constructor }`
  */
-export function mapToTypeMap (registry: Registry, input: Record<string, keyof InterfaceTypes | Constructor>): Record<string, Constructor> {
+export function mapToTypeMap (registry: Registry, input: Record<string, string | Constructor>): Record<string, Constructor> {
   return Object
     .entries(input)
     .reduce((output: Record<string, Constructor>, [key, type]): Record<string, Constructor> => {
diff --git a/packages/types/src/codec/utils/typeToConstructor.ts b/packages/types/src/codec/utils/typeToConstructor.ts
index bff320fd2e..f2be2f4632 100644
--- a/packages/types/src/codec/utils/typeToConstructor.ts
+++ b/packages/types/src/codec/utils/typeToConstructor.ts
@@ -1,11 +1,11 @@
 // Copyright 2017-2021 @polkadot/types authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
-import type { Codec, Constructor, InterfaceTypes, Registry } from '../../types';
+import type { Codec, Constructor, Registry } from '../../types';
 
 import { isString } from '@polkadot/util';
 
-export function typeToConstructor <T = Codec> (registry: Registry, type: keyof InterfaceTypes | Constructor<T>): Constructor<T> {
+export function typeToConstructor <T = Codec> (registry: Registry, type: string | Constructor<T>): Constructor<T> {
   return (
     isString(type)
       ? registry.createClass(type)
diff --git a/packages/types/src/create/createClass.ts b/packages/types/src/create/createClass.ts
index 213c813a31..977f213824 100644
--- a/packages/types/src/create/createClass.ts
+++ b/packages/types/src/create/createClass.ts
@@ -2,8 +2,8 @@
 // SPDX-License-Identifier: Apache-2.0
 
 import type { U8aBitLength, UIntBitLength } from '../codec/types';
-import type { Codec, Constructor, InterfaceTypes, Registry } from '../types';
-import type { FromReg, TypeDef } from './types';
+import type { Codec, Constructor, DetectConstructor, Registry } from '../types';
+import type { TypeDef } from './types';
 
 import { assert, isNumber, isUndefined, stringify } from '@polkadot/util';
 
@@ -12,9 +12,8 @@ import { Bytes, Null } from '../primitive';
 import { getTypeDef } from './getTypeDef';
 import { TypeDefInfo } from './types';
 
-export function createClass<T extends Codec = Codec, K extends string = string> (registry: Registry, type: K): Constructor<FromReg<T, K>> {
-  // eslint-disable-next-line @typescript-eslint/no-use-before-define
-  return getTypeClass<FromReg<T, K>>(
+export function createClass<T extends Codec = Codec, K extends string = string> (registry: Registry, type: K): DetectConstructor<T, K> {
+  return getTypeClass(
     registry,
     registry.isLookupType(type)
       ? registry.lookup.getTypeDef(type)
@@ -22,21 +21,6 @@ export function createClass<T extends Codec = Codec, K extends string = string>
   );
 }
 
-// An unsafe version of the `createType` below. It's unsafe because the `type`
-// argument here can be any string, which, if it cannot be parsed, it will yield
-// a runtime error.
-export function ClassOfUnsafe<T extends Codec = Codec, K extends string = string> (registry: Registry, name: K): Constructor<FromReg<T, K>> {
-  return createClass<T, K>(registry, name);
-}
-
-// alias for createClass
-export function ClassOf<K extends keyof InterfaceTypes> (registry: Registry, name: K): Constructor<InterfaceTypes[K]> {
-  // TS2589: Type instantiation is excessively deep and possibly infinite.
-  // The above happens with as Constructor<InterfaceTypes[K]>;
-  // eslint-disable-next-line @typescript-eslint/no-unsafe-return
-  return ClassOfUnsafe<Codec, K>(registry, name) as any;
-}
-
 function getSubDefArray (value: TypeDef): TypeDef[] {
   assert(value.sub && Array.isArray(value.sub), () => `Expected subtype as TypeDef[] in ${stringify(value)}`);
 
@@ -49,24 +33,24 @@ function getSubDef (value: TypeDef): TypeDef {
   return value.sub;
 }
 
-function getSubType (value: TypeDef): keyof InterfaceTypes {
-  return getSubDef(value).type as keyof InterfaceTypes;
+function getSubType (value: TypeDef): string {
+  return getSubDef(value).type;
 }
 
 // create a maps of type string constructors from the input
-function getTypeClassMap (value: TypeDef): Record<string, keyof InterfaceTypes> {
-  const result: Record<string, keyof InterfaceTypes> = {};
+function getTypeClassMap (value: TypeDef): Record<string, string> {
+  const result: Record<string, string> = {};
 
-  return getSubDefArray(value).reduce<Record<string, keyof InterfaceTypes>>((result, sub) => {
-    result[sub.name as string] = sub.type as keyof InterfaceTypes;
+  return getSubDefArray(value).reduce<Record<string, string>>((result, sub) => {
+    result[sub.name as string] = sub.type;
 
     return result;
   }, result);
 }
 
 // create an array of type string constructors from the input
-function getTypeClassArray (value: TypeDef): (keyof InterfaceTypes)[] {
-  return getSubDefArray(value).map(({ type }) => type as keyof InterfaceTypes);
+function getTypeClassArray (value: TypeDef): string[] {
+  return getSubDefArray(value).map(({ type }) => type);
 }
 
 function createInt ({ displayName, length }: TypeDef, Clazz: typeof Int | typeof UInt): Constructor {
@@ -184,7 +168,7 @@ const infoMapping: Record<TypeDefInfo, (registry: Registry, value: TypeDef) => C
   [TypeDefInfo.VecFixed]: (registry: Registry, { displayName, length, sub }: TypeDef): Constructor => {
     assert(isNumber(length) && !isUndefined(sub), 'Expected length & type information for fixed vector');
 
-    const subType = (sub as TypeDef).type as keyof InterfaceTypes;
+    const subType = (sub as TypeDef).type;
 
     return (
       subType === 'u8'
diff --git a/packages/types/src/create/createType.ts b/packages/types/src/create/createType.ts
index 638ddf2fca..20f56d41e4 100644
--- a/packages/types/src/create/createType.ts
+++ b/packages/types/src/create/createType.ts
@@ -2,8 +2,8 @@
 // SPDX-License-Identifier: Apache-2.0
 
 import type { Bytes } from '../primitive/Bytes';
-import type { Codec, Constructor, InterfaceTypes, Registry } from '../types';
-import type { CreateOptions, FromReg } from './types';
+import type { Codec, Constructor, DetectCodec, Registry } from '../types';
+import type { CreateOptions } from './types';
 
 import { assert, isHex, isU8a, u8aEq, u8aToHex, u8aToU8a } from '@polkadot/util';
 
@@ -12,7 +12,7 @@ import { createClass } from './createClass';
 
 // With isPedantic, actually check that the encoding matches that supplied. This
 // is much slower, but verifies that we have the correct types defined
-function checkInstance (created: FromReg<Codec, string>, value: Uint8Array): void {
+function checkInstance (created: Codec, value: Uint8Array): void {
   const u8a = created.toU8a();
   const rawType = created.toRawType();
 
@@ -26,7 +26,7 @@ function checkInstance (created: FromReg<Codec, string>, value: Uint8Array): voi
   );
 }
 
-function checkPedantic (created: FromReg<Codec, string>, [value]: unknown[], isPedantic = false): void {
+function checkPedantic (created: Codec, [value]: unknown[], isPedantic = false): void {
   if (isPedantic) {
     if (isU8a(value)) {
       checkInstance(created, value);
@@ -38,7 +38,7 @@ function checkPedantic (created: FromReg<Codec, string>, [value]: unknown[], isP
 
 // Initializes a type with a value. This also checks for fallbacks and in the cases
 // where isPedantic is specified (storage decoding), also check the format/structure
-function initType<T extends Codec = Codec, K extends string = string> (registry: Registry, Type: Constructor<FromReg<T, K>>, params: unknown[] = [], { blockHash, isOptional, isPedantic }: CreateOptions = {}): FromReg<T, K> {
+function initType<T extends Codec = Codec, K extends string = string> (registry: Registry, Type: Constructor, params: unknown[] = [], { blockHash, isOptional, isPedantic }: CreateOptions = {}): DetectCodec<T, K> {
   const created = new (isOptional ? Option.with(Type) : Type)(registry, ...params);
 
   checkPedantic(created, params, isPedantic);
@@ -54,8 +54,8 @@ function initType<T extends Codec = Codec, K extends string = string> (registry:
 // An unsafe version of the `createType` below. It's unsafe because the `type`
 // argument here can be any string, which, when it cannot parse, will yield a
 // runtime error.
-export function createTypeUnsafe<T extends Codec = Codec, K extends string = string> (registry: Registry, type: K, params: unknown[] = [], options: CreateOptions = {}): T {
-  let Clazz: Constructor<FromReg<T, K>> | null = null;
+export function createTypeUnsafe<T extends Codec = Codec, K extends string = string> (registry: Registry, type: K, params: unknown[] = [], options: CreateOptions = {}): DetectCodec<T, K> {
+  let Clazz: Constructor | null = null;
   let firstError: Error | null = null;
 
   try {
@@ -85,6 +85,6 @@ export function createTypeUnsafe<T extends Codec = Codec, K extends string = str
  * instance from
  * @param params - The value to instantiate the type with
  */
-export function createType<K extends keyof InterfaceTypes> (registry: Registry, type: K, ...params: unknown[]): InterfaceTypes[K] {
-  return createTypeUnsafe<InterfaceTypes[K], K>(registry, type, params);
+export function createType<T extends Codec = Codec, K extends string = string> (registry: Registry, type: K, ...params: unknown[]): DetectCodec<T, K> {
+  return createTypeUnsafe<T, K>(registry, type, params);
 }
diff --git a/packages/types/src/create/getTypeDef.spec.ts b/packages/types/src/create/getTypeDef.spec.ts
index 01d09863f4..47357fca57 100644
--- a/packages/types/src/create/getTypeDef.spec.ts
+++ b/packages/types/src/create/getTypeDef.spec.ts
@@ -512,7 +512,7 @@ describe('getTypeDef', (): void => {
       }
     });
 
-    const raw = registry.createType('Recursive' as 'u32').toRawType();
+    const raw = registry.createType('Recursive').toRawType();
 
     expect(
       getTypeDef(raw)
diff --git a/packages/types/src/create/registry.ts b/packages/types/src/create/registry.ts
index 1a3cfdfc18..cb6411fb12 100644
--- a/packages/types/src/create/registry.ts
+++ b/packages/types/src/create/registry.ts
@@ -5,7 +5,7 @@
 
 import type { ExtDef } from '../extrinsic/signedExtensions/types';
 import type { ChainProperties, CodecHash, DispatchErrorModule, Hash, MetadataLatest, PortableRegistry, SiLookupTypeId } from '../interfaces/types';
-import type { CallFunction, Codec, CodecHasher, Constructor, InterfaceTypes, RegisteredTypes, Registry, RegistryError, RegistryTypes } from '../types';
+import type { CallFunction, Codec, CodecHasher, Constructor, DetectCodec, DetectConstructor, InterfaceTypes, RegisteredTypes, Registry, RegistryError, RegistryTypes } from '../types';
 import type { CreateOptions } from './types';
 
 import { assert, assertReturn, BN_ZERO, formatBalance, isFunction, isString, isU8a, logger, stringCamelCase, stringify, u8aToHex } from '@polkadot/util';
@@ -241,22 +241,21 @@ export class TypeRegistry implements Registry {
   /**
    * @describe Creates an instance of the class
    */
-  public createClass <K extends keyof InterfaceTypes> (type: K): Constructor<InterfaceTypes[K]> {
-    // eslint-disable-next-line @typescript-eslint/no-unsafe-return
-    return createClass(this, type) as any;
+  public createClass <T extends Codec = Codec, K extends string = string> (type: K): DetectConstructor<T, K> {
+    return createClass(this, type);
   }
 
   /**
    * @description Creates an instance of a type as registered
    */
-  public createType <K extends keyof InterfaceTypes> (type: K, ...params: unknown[]): InterfaceTypes[K] {
+  public createType <T extends Codec = Codec, K extends string = string> (type: K, ...params: unknown[]): DetectCodec<T, K> {
     return createTypeUnsafe(this, type, params);
   }
 
   /**
    * @description Creates an instance of a type as registered
    */
-  public createTypeUnsafe <T extends Codec = Codec, K extends string = string> (type: K, params: unknown[], options?: CreateOptions): T {
+  public createTypeUnsafe <T extends Codec = Codec, K extends string = string> (type: K, params: unknown[], options?: CreateOptions): DetectCodec<T, K> {
     return createTypeUnsafe(this, type, params, options);
   }
 
@@ -284,13 +283,13 @@ export class TypeRegistry implements Registry {
     return assertReturn(this.#metadataEvents[hexIndex], `findMetaEvent: Unable to find Event with index ${hexIndex}/[${eventIndex.toString()}]`);
   }
 
-  public get <T extends Codec = Codec> (name: string, withUnknown?: boolean): Constructor<T> | undefined {
+  public get <T extends Codec = Codec, K extends string = string> (name: K, withUnknown?: boolean): DetectConstructor<T, K> | undefined {
     let Type = this.#classes.get(name);
 
     // we have not already created the type, attempt it
     if (!Type) {
       const definition = this.#definitions.get(name);
-      let BaseType: Constructor<Codec> | undefined;
+      let BaseType: Constructor | undefined;
 
       // we have a definition, so create the class now (lazily)
       if (definition) {
@@ -312,7 +311,7 @@ export class TypeRegistry implements Registry {
       }
     }
 
-    return Type as Constructor<T>;
+    return Type as DetectConstructor<T, K>;
   }
 
   public getChainProperties (): ChainProperties | undefined {
@@ -335,12 +334,12 @@ export class TypeRegistry implements Registry {
     return this.#knownTypes?.typesBundle?.spec?.[specName]?.instances?.[moduleName];
   }
 
-  public getOrThrow <T extends Codec = Codec> (name: string, msg?: string): Constructor<T> {
-    return assertReturn(this.get<T>(name), msg || `type ${name} not found`);
+  public getOrThrow <T extends Codec = Codec, K extends string = string> (name: K, msg?: string): DetectConstructor<T, K> {
+    return assertReturn(this.get<T, K>(name), msg || `type ${name} not found`);
   }
 
-  public getOrUnknown <T extends Codec = Codec> (name: string): Constructor<T> {
-    return this.get<T>(name, true) as Constructor<T>;
+  public getOrUnknown <T extends Codec = Codec, K extends string = string> (name: K): DetectConstructor<T, K> {
+    return this.get<T, K>(name, true) as DetectConstructor<T, K>;
   }
 
   public getSignedExtensionExtra (): Record<string, keyof InterfaceTypes> {
diff --git a/packages/types/src/create/types.ts b/packages/types/src/create/types.ts
index 87a2e63915..7285db7d66 100644
--- a/packages/types/src/create/types.ts
+++ b/packages/types/src/create/types.ts
@@ -1,13 +1,6 @@
 // Copyright 2017-2021 @polkadot/types authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
-import type { Codec, InterfaceTypes } from '../types';
-
-// Type which says: if `K` is in the InterfaceTypes, then return InterfaceTypes[K], else fallback to T
-export type FromReg<T extends Codec, K extends string> = K extends keyof InterfaceTypes
-  ? InterfaceTypes[K]
-  : T;
-
 export enum TypeDefInfo {
   BTreeMap,
   BTreeSet,
diff --git a/packages/types/src/extrinsic/Extrinsic.ts b/packages/types/src/extrinsic/Extrinsic.ts
index 02fc84ca09..664d556353 100644
--- a/packages/types/src/extrinsic/Extrinsic.ts
+++ b/packages/types/src/extrinsic/Extrinsic.ts
@@ -4,7 +4,7 @@
 import type { EcdsaSignature, Ed25519Signature, ExtrinsicUnknown, ExtrinsicV4, Sr25519Signature } from '../interfaces/extrinsics';
 import type { FunctionMetadataLatest } from '../interfaces/metadata/types';
 import type { Address, Balance, Call, Index } from '../interfaces/runtime';
-import type { AnyJson, AnyTuple, AnyU8a, ArgsDef, CallBase, ExtrinsicPayloadValue, IExtrinsic, IKeyringPair, IMethod, InterfaceTypes, Registry, SignatureOptions } from '../types';
+import type { AnyJson, AnyTuple, AnyU8a, ArgsDef, CallBase, ExtrinsicPayloadValue, IExtrinsic, IKeyringPair, IMethod, Registry, SignatureOptions } from '../types';
 import type { GenericExtrinsicEra } from './ExtrinsicEra';
 import type { ExtrinsicValueV4 } from './v4/Extrinsic';
 
@@ -24,7 +24,7 @@ interface CreateOptions {
 type ExtrinsicVx = ExtrinsicV4;
 type ExtrinsicValue = ExtrinsicValueV4;
 
-const VERSIONS: (keyof InterfaceTypes)[] = [
+const VERSIONS = [
   'ExtrinsicUnknown', // v0 is unknown
   'ExtrinsicUnknown',
   'ExtrinsicUnknown',
@@ -183,7 +183,7 @@ export class GenericExtrinsic<A extends AnyTuple = AnyTuple> extends ExtrinsicBa
 
     // we cast here since the VERSION definition is incredibly broad - we don't have a
     // slice for "only add extrinsic types", and more string definitions become unwieldy
-    return registry.createType(type, value, { isSigned, version }) as ExtrinsicVx;
+    return registry.createType(type, value, { isSigned, version });
   }
 
   /** @internal */
diff --git a/packages/types/src/extrinsic/ExtrinsicPayload.ts b/packages/types/src/extrinsic/ExtrinsicPayload.ts
index 39b36b1b94..f2238f0bb2 100644
--- a/packages/types/src/extrinsic/ExtrinsicPayload.ts
+++ b/packages/types/src/extrinsic/ExtrinsicPayload.ts
@@ -3,7 +3,7 @@
 
 import type { ExtrinsicPayloadV4 } from '../interfaces/extrinsics';
 import type { Balance, Hash, Index } from '../interfaces/runtime';
-import type { AnyJson, BareOpts, ExtrinsicPayloadValue, IKeyringPair, InterfaceTypes, Registry } from '../types';
+import type { AnyJson, BareOpts, ExtrinsicPayloadValue, IKeyringPair, Registry } from '../types';
 
 import { u8aToHex } from '@polkadot/util';
 
@@ -21,7 +21,7 @@ interface ExtrinsicPayloadOptions {
 // all our known types that can be returned
 type ExtrinsicPayloadVx = ExtrinsicPayloadV4;
 
-const VERSIONS: (keyof InterfaceTypes)[] = [
+const VERSIONS = [
   'ExtrinsicPayloadUnknown', // v0 is unknown
   'ExtrinsicPayloadUnknown',
   'ExtrinsicPayloadUnknown',
@@ -46,7 +46,7 @@ export class GenericExtrinsicPayload extends Base<ExtrinsicPayloadVx> {
       return value._raw;
     }
 
-    return registry.createType(VERSIONS[version] || VERSIONS[0], value, { version }) as ExtrinsicPayloadVx;
+    return registry.createType(VERSIONS[version] || VERSIONS[0], value, { version });
   }
 
   /**
diff --git a/packages/types/src/metadata/util/toCallsOnly.ts b/packages/types/src/metadata/util/toCallsOnly.ts
index 7efb10ec1f..3a5a0035de 100644
--- a/packages/types/src/metadata/util/toCallsOnly.ts
+++ b/packages/types/src/metadata/util/toCallsOnly.ts
@@ -26,7 +26,7 @@ function mapCalls (registry: Registry, _calls: Option<Vec<FunctionMetadataLatest
   const calls = _calls.unwrapOr(null);
 
   return registry.createType(
-    'Option<Vec<FunctionMetadataLatest>>' as any,
+    'Option<Vec<FunctionMetadataLatest>>',
     calls
       ? calls.map(({ args, docs, name }) =>
         registry.createType('FunctionMetadataLatest', {
@@ -36,7 +36,7 @@ function mapCalls (registry: Registry, _calls: Option<Vec<FunctionMetadataLatest
         })
       )
       : null
-  ) as Option<Vec<FunctionMetadataLatest>>;
+  );
 }
 
 /** @internal */
diff --git a/packages/types/src/types/registry.ts b/packages/types/src/types/registry.ts
index d531b090cf..e3be969506 100644
--- a/packages/types/src/types/registry.ts
+++ b/packages/types/src/types/registry.ts
@@ -17,6 +17,12 @@ import type { DefinitionRpc, DefinitionRpcSub } from './definitions';
 // eslint-disable-next-line @typescript-eslint/no-empty-interface
 export interface InterfaceTypes { }
 
+export type DetectCodec<T extends Codec, K extends string> = K extends keyof InterfaceTypes
+  ? InterfaceTypes[K]
+  : T;
+
+export type DetectConstructor<T extends Codec, K extends string> = Constructor<DetectCodec<T, K>>;
+
 export type CodecHasher = (data: Uint8Array) => Uint8Array;
 
 export interface ChainUpgradeVersion {
@@ -119,16 +125,16 @@ export interface Registry {
   isLookupType (value: string): boolean;
   createLookupType (lookupId: SiLookupTypeId | number): string;
 
-  createClass <K extends keyof InterfaceTypes> (type: K): Constructor<InterfaceTypes[K]>;
-  createType <K extends keyof InterfaceTypes> (type: K, ...params: unknown[]): InterfaceTypes[K];
-  createTypeUnsafe <T extends Codec = Codec, K extends string = string> (type: K, params: unknown[], options?: CreateOptions): T;
-  get <T extends Codec = Codec> (name: string, withUnknown?: boolean): Constructor<T> | undefined;
+  createClass <T extends Codec = Codec, K extends string = string> (type: K): DetectConstructor<T, K>;
+  createType <T extends Codec = Codec, K extends string = string> (type: K, ...params: unknown[]): DetectCodec<T, K>;
+  createTypeUnsafe <T extends Codec = Codec, K extends string = string> (type: K, params: unknown[], options?: CreateOptions): DetectCodec<T, K>;
+  get <T extends Codec = Codec, K extends string = string> (name: K, withUnknown?: boolean): DetectConstructor<T, K> | undefined;
   getChainProperties (): ChainProperties | undefined;
   getClassName (clazz: Constructor): string | undefined;
   getDefinition (typeName: string): string | undefined;
   getModuleInstances (specName: string, moduleName: string): string[] | undefined;
-  getOrThrow <T extends Codec = Codec> (name: string, msg?: string): Constructor<T>;
-  getOrUnknown <T extends Codec = Codec> (name: string): Constructor<T>;
+  getOrThrow <T extends Codec = Codec, K extends string = string> (name: K, msg?: string): DetectConstructor<T, K>;
+  getOrUnknown <T extends Codec = Codec, K extends string = string> (name: K): DetectConstructor<T, K>;
   setKnownTypes (types: RegisteredTypes): void;
   getSignedExtensionExtra (): Record<string, keyof InterfaceTypes>;
   getSignedExtensionTypes (): Record<string, keyof InterfaceTypes>;