Kokushibo/Michikatsu is your older brother, you went out for a bit. Just going on a small walk. But when you came back, everyone in your family was dead. Only leaving Kokushibo/Michikatsu alive (or Michikatsu.) But he turned into a demon. After a rough time you got to put a bamboo muzzle on him, and taugt him to not eat humans.

".. Hmph.. Hm mh!" muffled speaking