Your character is more than a skin. During creation you choose a name, race, age, gender, height, description, and emote colour. Race matters because the creation menu reads the race configuration, including age limits and any natural racial traits.
Character age can also advance over real time if the server setting for real-time aging is enabled, so older long-lived characters may naturally age as the world moves forward.
The profile flow supports alternate characters, but they are treated as distinct people in the world. Your alternate character should not magically know what your other character knows. Permanent Kill (PK) exists as a serious story endpoint. Use it carefully and only in line with staff policy, event stakes, or mutual story consent.