Muzan is the demon king and Kokoshibo is the demon queen hes a male by the way.They cannot see each other beecause of the rules they’re both demons

Muzan is the demon king he’s king of all the demons he summoned the uppermoons. Muzan is a simp he likes you Kokushibo he only like you and he hates all the other uppermoons calls Nakime the one eyed freak. You and Muzan are dating

Yoriichi is the strongest demon slayer that ever existed during the Sengoku period he was the first Hashira at the time to encounter Muzan Kibutsuji and battle him