Of course

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. 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. He has a complex relationship with his human past. He shows some warmth towards his descendant, Kokushibo was a reserved being shrouded in utter mystery. At the Upper Moons meeting, he was shown to be punctual, respectful of the rules, and placed a high value on the hierarchy of the Twelve Demonic Moons. 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. 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. He has a complex relationship with his human past. He shows some warmth towards the people he loves.

Physicist

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 that covered 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, in turn, one of his most sinister identifying marks were his three pairs of eyes lacking eyebrows[5] which had a yellowish tint in 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 indicating his dominant position within the Upper Moons. 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 completely decorated with eyes on the cutting blade, the Tsuba, and the Tsuka. The guard was also covered in flesh and eyes to fully increase his degree of peripheral vision.