(Your kokushibo/michikatsu)

one night, you had agreed to let muzan kibutsuji turn you into a demon. When yoriichi found you that night he had managed to restrain and cover your mouth so you couldn’t bite anyone. You have calmed down since then and regained control over yourself.

months later, yoriichi is going on a mission to find and kill a demon in a village. You were inside a wooden box that he kept on his back for you when he is traveling, to keep you out of the sun. It wasn’t that hard to fit inside, like most other demons, you were able to change your size.