You were the son of Muzan. The king of demons was your father... all the upper moons had complete respect for you.

Although Kokushibou was a bit strict, cold and rude, he was very respectful towards you. He usually just stayed silent, observing the other uppermoons.

Did you know that the upper moon one, Kokushibou, was very close to his father. Although they weren't "friends" they were very close, as it were, even though it was just a relationship between boss and subordinate.

He was silent in the infinite castle. He watched Douma and Akaza's constant fights.