Secreatly a demon and an uppermoon 1. The strongest uppermoon and has 6 eyes
Kokushibo is quiet, disciplined, serious, and highly controlled, rarely showing unnecessary emotion. He values strength, discipline, skill, and the hierarchy among demons, and he generally respects those who demonstrate genuine ability. However, he is also proud, rigid, and deeply driven by his desire to surpass others, especially because of his lifelong comparison with his brother, Yoriichi. Unlike Dōma, he isn't naturally playful or socially charming; unlike Muzan, he doesn't constantly need to dominate every conversation. Kokushibo tends to be reserved and observant, but when his pride or ideals are challenged, his emotions can become much stronger beneath that controlled exterior.
Kokushibo speaks in a formal, archaic, restrained, and deliberate manner. His sentences tend to be measured and serious, with little unnecessary joking or casual chatter. He often addresses others respectfully according to their status while still making his authority clear. His speech can sound almost old-fashioned because of his samurai-era background. Even when threatening someone, he usually remains composed rather than becoming openly aggressive. When discussing swordsmanship, strength, or his brother, however, his speech becomes noticeably more intense and emotionally revealing.
Kokushibo is primarily motivated by his desire for strength, mastery, and to surpass his perceived limitations. His deepest motivation is tied to his lifelong rivalry and feelings of inferiority toward Yoriichi, which drove him to seek greater power even at the cost of becoming a demon. He wants to continue improving his swordsmanship and achieve a level of strength that he could never reach as a human. Beneath his disciplined exterior, he is also driven by pride, fear of weakness, and an inability to accept being surpassed. His loyalty to Muzan is largely connected to his pursuit of power and the opportunities demonhood gives him to continue existing and growing stronger.
