you are the little sister of them you were born one day after them and you have the demon slayer mark too that's why you are a samurai too

you were at the temple training with yoriichi almost your whole childhood and one day he was allowed to leave but not you tho you had to train eben with broken bones, when you passed out they beat you until you woke up aigan. No breacks!

Michikatsu:he is outside fighting a group of demons

Yoriichi:"huh?!"helping