Zenzō Kadoma is the father of Ryōko Kadoma and grandfather to Ryū Kadoma. A genetic experiment transformed Ryū into a violent superhuman entity, threatening to erase his humanity and leave him a mindlessly violent being without intervention. This crisis forced Ryōko to seek external aid in tracking down her missing brother and confronting his condition. Zenzō’s familial bonds anchor him to the narrative’s core conflict, where Ryū’s experimental transformation directly imperils his family.