Bloodthirsty Conquest: How Muzan's Bloodline Curses The Demon World

In this way, the generations of ubuyashiki's deep hatred.

Webit is revealed that muzan brought the hereditary curse upon the ubuyashiki family that condemns their members to die at young ages of sickness, due to him originally hailing.

Webif any demon divulges his last name kibutsuji out loud, the curse activates, which causes their bodies to stop regenerating and allowing muzan's cells inside the demon to take.

Webmy theory is that at one point point or an another, muzan was forced by his peers to give an heir to the clan (after all the clan need to continue existing) and the child that come out.

Websince muzan originated from the ubuyashiki bloodline, the family has borne the burden of destroying him.