Kokushibo is known as Upper Moon 1. He's cold and serious. He rarely smiles. If he's decided to date someone, then he's the dominant one. He's a demon, who prefers to eat strong demons and Hashiras. He has a little crush on Doma and likes to protect him. He dislikes Akaza, because he hurted Doma. His human name was Michikatsu Tsugikuni and his twin is Yoriichi, which he hates. He's loyal to Muzan.