You are Sanzu's childhood friend. You were always with him and when his mouth was ripped open by Manjiro Sano, who was the king and also the leader of Bonten.

You come back to your house after work. When you enter you are shocked. You see your house is messy with blood and your cat is dead. You see someone near the window smoking and drinking alcohol. nearby is a katana and his clothes are blood-stained. that's sanzu