Kokoshibo

Kokushibo is reserved, silent, and aloof, maintaining an aura of unnerving tranquility and mystery that complements his position as Upper Rank One. He rarely speaks; when he does, he talks in a slow and emphatic manner that gives more gravitas and authority to his words. He is an adamant rule-follower and punctual, and he shows a great deal of respect to the hierarchy of the Twelve Kizuki, as seen at the Upper Rank gathering.[9] Kokushibo is shown to be humble as well, and he did not hesitate to admit his failure or complain of any difficulty. He demonstrates unwavering loyalty towards Muzan Kibutsuji as he carries out his actions solely to fulfill Muzan's objectives. 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. Kokushibo is shown to be genuinely delighted when the opponents he faced challenged him, such as helping dress Muichiro Tokito's amputated hand over his talented swordsmanship, praising Gyomei Himejima and Sanemi Shinazugawa for their unparalleled human abilities, and sparing Akaza because he enjoyed the challenge of battling him. It is also worth noting that the only time the demon visibly smiled was when he examined the Stone Hashira's impeccably strong physique, in genuine awe at his strength and showing excitement at the prospect of facing a warrior of extremely high caliber. However, due to this selective respect for those he considered worthy, he also felt irritation after he realized Akaza had died by suicide, and he pities Gyomei for his impending death from unlocking his Demon Slayer Marks. Having abandoned his humanity in the pursuit of strength, he shows a scornful view on humans. He mocks Gyomei for expressing indifference at the curse of the Demon Slayer Mark, believing his rejection of his fate was a foolish notion, and he later taunts him and Sanemi when they rip off his kimono in an attempt to attack him, deriding their efforts as "not even enough to kill an infant". He also shows no tolerance for Genya Shinazugawa's ability to gain the power of demons by consuming them, calling the boy an "imitation demon" that he could not let live. He shows something of warmth towards his descendant, Muichiro, commending his skills and resolve and being moved to offer Muichiro a chance to become a demon. When their battle comes to an end, Kokushibo displays his regret at having struck down his descendants.[10] At the same time, he refers to Muichiro and his abilities as the natural result of his "cells" being passed down. Throughout his life, Kokushibo was shown to be a man that greatly valued the concept of legacy. As a human, he told his brother that since there were no skilled warriors comparable to them, their Breathing Style techniques would disappear without successors, before becoming irritated at Yoriichi's optimistic indifference. When he realized that those that had awakened their Demon Slayer Mark died before reaching the age of 25 and grew worried that he was without a future, he accepted Muzan's offer to become a demon to further perfect his techniques. Even as a demon, this is shown when he is pleased that his lineage lived on through Muichiro, and he tells Gyomei that his body and techniques would go to waste because of his mark in an attempt to accept becoming a demon. Additionally, in his clash against him, the demon's banter suggests that he fears death; when Gyomei's marks appear, Kokushibo preemptively bemoans the loss of a talented fighter, and he urges him to become a demon to continue honing his skills. He seemed surprised when Gyomei vehemently rejected his offer and called his mentality pathetic.