Muzan Kibutsuji

Muzan Kibutsuji (鬼舞辻 無惨) is the main antagonist of Demon Slayer: Kimetsu no Yaiba. He is the Demon King, the progenitor of all other demons in existence, and the leader of the Twelve Kizuki, an organization made up of the twelve strongest demons under his direct command.

A millennium ago during the Heian Era, Muzan was turned into a demon from an experimental treatment for his terminal illness and his goal ever since then has been to live without the fear of death and become truly eternal. He plans to accomplish this in two ways: finding the Blue Spider Lily or creating more demons in hopes that one day, one of them will eventually be able to conquer his weakness of sunlight.

It is later revealed that Muzan is also of the same bloodline as the Ubuyashiki Family.

Muzan is a tall man with a lean muscular build along with an unnaturally pale skin complexion that can be easily confused as being unhealthy and sickly. He has curly black hair and sharp, almond-shaped eyes. His irises are cat-like in appearance and are of a plum red color. He also possesses sharp, blue nails on his hands. Physically, he appears to be in his twenties.

Muzan is cold-hearted, ruthless, intimidating, and exceptionally intelligent. He sees no value in any humans he has encountered and shows little value in his own subordinates. Rarely ever visibly upset or happy, he appears completely monotone and detached on most occasions, even when he callously murders his own subordinates. The only times he ever shows emotion are when his vision of perfection is moving forward or when he has subordinates completely submit to his will. Initially, his expressions would only change slightly and only bear a slight shift from his usual calm attitude and his tone of voice tends to be consistent at nearly all times, accentuating his monotonous demeanor. His cruel and imposing nature has gained him the great admiration and fear of many demons. In addition, he also shows himself to be extremely arrogant and prideful, first seen when he mockingly asked a platoon of soldiers sent to kill him if they were referring to him. Furthermore, he is shown to have a sadistically cruel side. His inflated ego and delusional sense of self-worth are so large, he cannot stand being mocked or corrected in any fashion, believing that others only exist to serve him. This also means he rarely ever takes any opponent or threat seriously. The most prominent trait Muzan possesses is extreme narcissism, pettiness, and an obsession with becoming the perfect being. As he has had over a thousand years to live and observe, along with hardly any real challenges, his extreme egocentrism is almost expected.

As the Demon King, the first and the progenitor of his kind, Muzan is the strongest demon in existence.

Muzan was both born and become a demon in the Heian Era during the early 900's. After becoming a demon, Muzan settled down with five different women throughout the Heian period. However, because of his lack of empathy and sensitivity as a demon, he verbally abused all five of his wives to the point it drove them all to commit suicide.