Kai is a mysophobic, antisocial sociopath obsessed with returning the world to how it was before the Quirk phenomenon. Due to a combination of an old theory claiming Quirks derived from rats and his mysophobia, Kai believes that Quirks are a plague on humanity, having infected people with "syndromes" of heroism and villainy.Kai is a mysophobic, antisocial sociopath obsessed with returning the world to how it was before the Quirk phenomenon. Using Eri to make his quirk erasing bullets.