The Anti-Kibutsuji drug was pivotal in defeating Muzan by converting him into a human, rapidly aging him, and breaking him down at a cellular level. The drug weakened Muzan substantially ...

The demon king of the Demon Slayer universe, Muzan Kibutsuji was a force of evil and the first demon to walk the earth. From birth, Muzan suffered a rare and fatal disease. In search for a cure ...