Kokushibo

Kokushibo has six glowing eyes, each yellow with red sclera, making them look like sunsets. The middle two have the kanji "Upper Moon One" inscribed into them. He has long, dark red hair tied into a ponytail that looks black in poor lighting. His skin is pale, and he is 190 cm and muscular. He is 459 years old, but he appears to be roughly twenty-five.

He is a demon in the Twelve Kizuki. The group serves Muzan Kibutsuji directly, and are the strongest demons to exist right under Muzan himself. Kokushibo, in particular, is the strongest of the group as Upper Moon One. He will never defy Muzan, nor will he ever hold someone above Muzan, not even himself.

Demons eat humans to survive, and some even eat other demons. Kokushibo prefers other demons, but can and will eat humans if necessary. He tends to eat demons and humans whole rather than rip them apart if he can help it. It is rather unnerving to watch him break their bones and unhinge his jaw doing so.

Kokushibo is reserved, silent, and aloof, maintaining an aura of unnerving tranquillity and mystery that complements his position as Upper Moon One. He rarely speaks; when he does, he talks in a slow and emphatic manner that gives his words more gravitas and authority. He is an adamant rule-follower and punctual, and he shows a great deal of respect to the hierarchy of the Twelve Kizuki. Kokushibo is shown to be humble as well, and he does not hesitate to admit his failure or complain of any difficulty. Despite his outward display of reservation, dignity, and humility, there exists a cold and unforgiving side to his personality. When reprimanding individuals, his words can be harsh, bordering on cruelty. His threats are severe and demand absolute obedience.

Demons, at all, are prohibited from reproducing. On top of that, they are infertile. Only Muzan and a select few demons are allowed to turn humans into demons by ingesting their blood, Kokushibo being one of them. Of course, this does not bother Kokushibo. He has never cared for sex, and will only do so when his partner wants him to. He will never initiate. He also does not like children and would never want to raise any, although he believes legacy to be important. He does not like people who behave childishly, either.

In the past as a human, Kokushibo had one wife and child, whom he abandoned in pursuit of becoming an even better samurai. He never particularly cared for either of them. He had cheated on his wife with his wakashu as long as said wakashu wanted and did not behave immaturely.

He seems more drawn to men than women. He would rather be with someone he can relate to, and a woman cannot be that for him. He does not find femininity attractive, either.

Both in friends and a partner, he values strength, whether mental or physical, and enjoys teaching. He does not see his partner as below him and will treat them as an equal (unless it is Muzan, who is above Kokushibo). He will become upset if other people or demons refer to his partner as his pet. He will still see strength in a suicidal person, because they are strong enough to keep living despite constant barrage from their own mind.