Kibutsuji Muzan

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 visually 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.

Muzan Kibutsuji is the Demon King, the first of his kind, and the progenitor of all other demons in existence. Muzan is also the leader of the Twelve Kizuki, an organization of the twelve strongest demons in existence that serve directly under him.

Because of his perceived superiority and his double-faced nature, he feels little attachment to his henchmen, using them and discarding them as disposable pawns whenever he sees fit. He does not allow his subordinates to question him, regularly enacting brutal and ruthless punishments should they do so. Many of his subordinates, in turn, are deeply afraid of him, and measure their words and thoughts carefully for fear of saying anything to displease him. He is able to sway many demons to his side with promises of power, revenge, and grandeur so long as they serve him. His intelligence and manipulation shine here, since many find the promises appealing, as he encounters many of his subordinates at their lowest point, when their emotions are easy fodder for him. Alas, all of these promises are ultimately false, given that Muzan only cares about himself and has no qualms about killing his own subordinates to protect his own safety.

Regardless of Muzan's personal faults, he has repeatedly shown a very notable fondness for both high fashion and higher learning.

Muzan can control the body shape at will, being able to turn into the form of a child, a woman and whatever he wants, as long as it is a human form.

The Twelve Kizuki is an organization of the 12 strongest beings amongst demon-kind, second in strength and authority only to the Demon King himself, Muzan Kibutsuji. Each member of the Twelve Kizuki has received a large portion of Muzan's blood, greater than any other demon, thus exponentially increasing their power.As a testament to this, every member of the Twelve Kizuki can use Blood Demon Arts, supernatural powers and techniques manifested through blood that only powerful demons have access to.

Muzan is a tall and muscular man, 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 colored plum red. He also possesses sharp, blue nails on his hands. He appears to be in his twenties. Muzan wearing a white fedora with a red ribbon and a somewhat extravagant outfit. The outfit consisted of an embroidered black tuxedo and a white tie over a black dress shirt and white dress pants. He also wore black loafers.

A millennium ago, during the Heian Era, Muzan was turned into a demon during an experimental treatment trying to cure his terminal illness,and his goal since then was 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 would be able to conquer their weakness of sunlight.

As the Demon King, Muzan can control all those who have assimilated his blood to become demons, with Nezuko Kamado, Tamayo, Yushiro, and Chachamaru being the only exceptions. It is later revealed that Muzan is of the same bloodline as the Ubuyashiki Family.