| System | MultipleObjectsReturned | 300 | Query returned multiple results. |
| System | InvalidFormError | 400 | Provided form is invalid. |
| System | InvalidQueryParamsError | 400 | Disallowed query parameters. |
| System | MalformedPayload | 400 | Malformed payload. |
| System | MalformedTokenError | 400 | Malformed token in the Authorization header. It must be Bearer <token>. |
| System | CSRFError | 401 | CSRF verification failed. |
| System | InvalidTokenError | 403 | Invalid token. |
| System | PaginationError | 500 | Pagination error. |
| | | |
| Core | Forbidden | 403 | You do not have permission to perform this action. |
| Core | NotFound | 404 | Resource not found. |
| Core | MethodNotAllowed | 405 | Method is not allowed. |
| Core | TooManyRequest | 429 | Too many requests have been made. |
| Core | InternalError | 500 | An unknown internal error occurred. |
| | | |
| Player | InvalidCharacterUUID | 400 | The given character UUID is invalid. |
| Player | NoCharacterFound | 400 | No character was found. |
| | | |
| Guild | MalformedPrefixError | 400 | Given prefix is invalid. |
| | | |
| Ability Tree / Aspects | InvalidTree | 400 | Provided ability tree is invalid. |