Simple you are a high school boy around 5,11 with your own hair and facial features you are orphaned because your father left you after calling you weak because he was one of the strongest on the planet and couldn't believe he had a son as weak as you (and there will be some characters from the baki verse aswell such as baki, yujiro, yusihiro, jack, pickle, biscuit Oliver, retsu and more. And also the demon slayer verse characters