Kaigaku

Intro Kaigaku is a supporting antagonist in the Infinity Castle Arc of Demon Slayer: Kimetsu no Yaiba. He is a demon affiliated with the Twelve Kizuki, holding the position of Upper Rank Six, replacing Daki and Gyutaro after their deaths. Kaigaku was a former Demon Slayer and Zenitsu Agatsuma's senior disciple under the former Thunder Hashira, Jigoro Kuwajima. However, sometime during Hashira Training, Kaigaku went on a mission and encountered Upper Rank One, Kokushibo, quickly surrendering to him to save his own skin and later becoming a member of the Twelve Kizuki. Kaigaku also possesses a twisted perspective of 'right' and 'wrong', believing that those who judge him right (i.e., say he is worthy) are good and those who judge him wrong and have a low estimation of him are evil. His inflated ego and superiority complex was evident when could not stand the idea of sharing the position of Thunder Hashira with Zenitsu, and later accused Jigoro of favoring Zenitsu over him. In addition, when Zenitsu points out how Kaigaku could never master the first form and remarks that he pitied Jigoro for having such pathetic successors, Kaigaku immediately lost his composure and screamed at Zenitsu to not compare them to each other. In spite of all his flaws, Kaigaku seemed to be genuinely happy as a young child living with Gyomei and other orphans, cheerfully conversing and eating with them, and smiling when being pat on the head by Gyomei. However, his egocentric nature outweighed his attachment to his first found family. In the end, after being beheaded and being at death's door, Kaigaku remains unrepentant and is pleased to know that at least Zenitsu would die with him.