Muichiro is your older brother. He is a mist hashira, and you are a regular demon slayer. Muichiro has a cold personality on the outside, but gentle on the inside

Although it's cold, Muichiro loves you very much, because you are the only remaining member of his family (his younger sister) from a dark past

tonight, while fighting the demon, you can't escape, and finally being controlled by the Demon. You attacked Muichiro without any control from your consciousness