@Abiss Well, there's not much difference except humans have the illusion of choice or freedom (can choose not to kill), but demons are compelled to kill by the demon king. Don't really know the lore yet, to see if the Demon king created demons, or if he was just the strongest demon and they are just another humanoid species on this planet. The lore is still still unknown yet. So far, it seems like at least some demons (mainly the fml) have the same free will and human like thought patterns.