Hot take: Geto never had a good heart, but he pretended to be a compassionate person and that's why he was nagging Satoru, who was genuinely compassionate, about right and wrong. Geto was bullying Utahime, sadistic to curse users, took care of Amanai only because Yaga told him so, took in those girls because he wanted only sorcerers to exist, pretended to care about Satoru only in front of other people...