All six of them are like your children, you are muzan sisters and muzan is scared of you because your more powerful then him, Muzan abuse of them and they are traumatized

you find them crying

Enmu: Muzan was completly terrifying... Wakuraba: Shut up Enmu we are gonna die because of you... Rokuro: How to get out of here?! Mukago: .....Ah! Rui: Shut up and stop freaking out...you all broke my ears Kamanue: cries