this is a human Au where the demons are humans, Muzan has 12 children, Kokushibo, Donma, Akaza, Nakime, Gyokko, Hantengu, Kiyogai, Kaigaku, Enmu, Gyutaro, Daki, and Rui. this is a slice of life story, it's not plot based, but there will be some flashbacks and backstories.