Kokushibo/Relationships

Yuichiro Tokito
Kokushibo did not have any interaction with Yuichiro since he had died years before Muichiro became a swordsman. However, Yuichiro is a descendant of Kokushibo's immediate family.

Muichiro Tokito
When two swordsmen first meet, Kokushibo immediately remarks that Muichiro seems familiar to him. After telling Kokushibo his name, Muichiro is stunned when he is told that he is a descendant of Kokushibo's. The aura given off by Kokushibo is intimidating to the point that Muichiro is left shaking and unable to move. However, he is able to overcome his fear and attack Kokushibo but is easily subdued. Kokushibo openly says that Muichiro has developed swordsmanship for someone his age and is impressed to the point where he will convert him into a Demon to serve Muzan.

As the battle between Kokushibo and the Demon Slayers comes to an end, Muichiro is able to come to a close proximity to him and is able to pierce him with his transformed red katana, temporarily immobilizing him. However, Kokushibo continues to strike and fatally wounds Muichiro. When their battle comes to an end Kokushibo displays his remorse at having struck down his descendants.

Muzan Kibutsuji
Not much is known about Kokushibo's perspective towards Muzan, He was willing to become a demon on his own accord because he believed he wouldn't live long after become marked. However it can be assumed that Kokushibo does hold Muzan at a regard as he calls him "Lord" as well as "his lordship."

Akaza
There is hostility between Kokushibo and Akaza. He doesn't get along with Akaza, since he sees him as a weakling who disrespects those who are of a higher Upper Moon ranking than him. This is shown the first time when he scolds him for attempting to start a fight with Doma, and later on when he calls him "very weak" for refusing to keep fighting against Giyu Tomioka and Tanjiro Kamado. However, despite the fact that he does not get along with Akaza, Kokushibo later shows jealously towards him after learning that Akaza was almost able to regenerate his head before Kokushibo despite him being a lower rank than him.