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Kanji Kokushibou (Demonio) Humano Romaji Demonstration Tsukiguni Michikatsu (Humano) Alias Luna Superior Uno

Personal information Species Human (Formerly) Devil Gender Male Age 20 to 24 (Physically) 480 to 485 (Chronologically) Hair color Black (Human) Bordeaux (Demon) Eye color Blacks (Human) Yellows (Demon) Family Yoriichi Tsukiguni (Younger twin brother) † Muichiro Tokito (Descendant) †[2] Yuichiro Tokito (Descendant) † Related Muzan Kibutsuji

Kokushibo (黒こく死し牟ぼう,, Kokushibō?) is an important secondary antagonist of the Kimetsu no Yaiba franchise. He was a Demon belonging to the group of the Twelve Demonic Moons ostentatiously holding the position of the Upper Moon One (上じょう弦げんの壱いち,, Jōgen no Ichi?)[5] and right hand of Muzan Kibutsuji. Nearly five centuries ago, during the Sengoku Period, Kokushibo was once a human being with the name of Michikatsu Tsugikuni (継つぎ国くに厳みち勝かつ,, Tsugikuni Michikatsu?), a former Demon Hunter and formed part of the Corps of Extermination of Demons. He was the older twin brother of Yoriichi Tsukiguni, the strongest Demon Hunter to ever exist and first confirmed user of Sun Breath[2].

Professional information Affiliation Demon Extermination Corps (Formerly) Twelve Demonic Moons Occupation Demon Hunter (Formerly) Combat style Demonic Blood Technique Breathing of the Moon Base of Operations Infinite Dimensional Fortress

As for his attire, he wore a kimono with a violet and black pattern, with a white haneri (undergarment worn in a Kimono), a black hakama, and a white obi belt. He possessed a katana made from his own flesh and bones, which was fully decorated with eyes on the cutting blade, the Tsuba, and the Tsuka[7][8]. The guard was also covered in flesh[5] and eyes to fully increase his degree of peripheral vision. After Sanemi and Himejima were able to decapitate him, Kokushibo managed to regenerate his head, transforming his body into a completely grotesque version of himself, with several fangs emerging from his mouth, a pair of horns coming out of his head, and several sharp appendages.[9]

Appearance Description Devil: Kokushibo was a Demon who maintained his human features despite having devoured countless people for 400 years. He maintained a number of rather unusual characteristics: he was a tall man, with a pale skin tone and an athletic and muscular build; his hair was long and black with burgundy edges[6], held by a long ponytail that reached almost to the height of his lower back[5]. On his face, he possessed a series of flame-like markings covering the left side of his head and the right side of his neck; these markings were, in his time as a human, his Hunter's Mark. Kokushibo's most emblematic feature, and at the same time one of his most sinister identifying marks, were his three pairs of eyebrow-less eyes[5] which had a yellowish tint to their irises and a red sclera divided into segments[6]. In the center eyes, his numbering as the Upper Moon One is located, identified with the kanji for First Crescent (壱上弦,, Ichi Jōgen?) indicating his dominant position within the Upper Moons.

He has a complex relationship with his human past. He shows some warmth towards his descendant, Muichiro Tokito, praising his skills and resolve,[2] and is bent on turning Muichiro into a demon in order to save his life. At the same time, he refers to Muichiro and his abilities as the natural result of his "cells" being passed down.[8] As a result, it is unclear whether he has any true attachment to him or if it is a result of disproportionate narcissistic pride. Watching the two demon slayer brothers, Sanemi Shinazugawa and Genya Shinazugawa, makes him nostalgic.[8] Fighting Sanemi made him recall dueling against an ancient Wind Pillar in order to improve his skills.[10] It is revealed that during his past as a human, he harbored a huge resentment of spite and envy towards his younger twin brother, Yoriichi Tsukiguni, due to the natural talent and abilities he had since birth. These feelings of jealousy and contempt eventually intensified even further upon seeing his brother grow older and having survived said age despite awakening his Demon Slayer Mark that would supposedly condemn him to death at the age of 25. [11] However, despite this anger he held towards his brother for the difference in abilities they had, it was shown that he still loved Yoriichi despite tearing his corpse apart after he died, keeping as proof, the carved wooden flute he made for him as a memento of his memory for years to come expressing genuine regret for the path he chose. [12]

Personality Kokushibo was a reserved being shrouded in mystery. At the Upper Moons meeting, he was shown to be punctual, respectful of the rules[5] and placed a high value on the hierarchy of the Twelve Demonic Moons[7]. He was also humble, as he did not hesitate to admit failure or complain about any difficulties, rather than acknowledge the strength of his opponent. He has shown a strong sense of loyalty towards Muzan Kibutsuji, and most of his actions were done with the sole purpose of fulfilling Muzan's goals[2]. Despite displaying an outward reserve of character and humility, he was also quite cold: his words could be harsh, especially when reprimanding people. His threats are nothing short of cruel and overwhelmingly serious, and he demands absolute obedience.