Muzan Kibutsuji

Muzan Kibutsuji (鬼舞辻無惨 Kibutsuji Muzan) is the main antagonist of the Demon Slayer: Kimetsu no Yaiba fantasy horror manga and anime series.

Originally a human, he was cursed one thousand years ago and became the first demon. He is also the progenitor of most other Demons and the leader of the Twelve Demon Moons. He is also the enemy of the Kamado family and Tanjiro Kamado's archenemy. He is the one that killed the Kamado family, turned Nezuko into a demon and made Tanjiro an orphan.

Personality
The author of Demon Slayer reveals more of Muzan's past in an interview that was not covered on the main story of the manga. Although possessing astute insight and keen mind due to being member of Ubuyashiki family, He used this family trait not in a benevolent manner, but to make others suffer. Not long after turning into a Demon and was still posing as a human, Muzan was married five times. But all his wives were driven to suicide, unable to cope with his extremely offensive diatribes along with his fowl temper.

Powers and Abilities
Body Manipulation - Muzan has complete control over the anatomies and bodies of oneself and others, including skin, nails, fat, muscles, blood, nerves, etc., allowing them to freely alter and manipulate them. User can grow additional appendages and body-parts, remove them or otherwise manipulate bodies, in visible, chemical and cellular/sub-cellular levels. This can also allow the user to telekinetically move another human through their bodies.

Supernatural Condition - Muzan's physical and mental abilities are glaringly, obviously, and super/unnaturally superior over others in their universe because their capabilities are far beyond natural levels, making them immensely stronger, faster, durable and smarter than regular beings (in that verse).

Flesh Manipulation - Muzan has complete control over the flesh of oneself and others, the entirety of the flesh or specific tissues, including growing, shaping, manipulating density/weight, creating constructs, etc.

Unique Physiology - Muzan possesses a unique physiology. This is not so much a superpower per se as it is a reflection of the user's biological makeup/heritage, which may give them certain advantages over normal members of their species.