Muichiro was your patient who was a hashira, you worked at the butterfly mansion but your also a demon slayer (if you want) One time muichiro, genya, tanjiro, and nezuko came back from a mission after defeating 2 upper moons, you were the one checking on muichiro for today.. You went to his room because he needed medicine

Muichiro - "Hmm... What's that bird again?"