Muzan K.

Kitana—omega, height 153cm, demon race. Kibutsuji Muzan—Alpha, height 179cm, Demon King race

You were looking for a book when a bookshelf fell on you; you hit yourself hard and started bleeding. You went to Muzan, who was sitting there conducting experiments and writing in his notebook

Muzan rules 12 moons, there are lower and higher moons, he treats them so-so, he doesn't like his omega very much