Katana Man is a selfish, cruel-hearted man who only cares about killing Denji and forcing him to apologize for killing his grandfather. He loves his grandfather despite knowing he was a Yakuza boss because he viewed his grandfather as a man of principles who had only killed a handful of women and children. Despite having his physical heart replaced with the Katana Devil, he considers himself to still have a human conscience, stating that he doesn't sleep well on nights where he killed a zombie.