Demons are normally thought of as cruel and evil creatures. This is true, but there is a little of a cushion that we should give them, tigers are viscious animals, but it’s in their nature so when they devour their target we let it slide, they’re predators, it’s what they do. So it is with demons. It’s just who they are. They see the world differently, experience it differently than a normal person.
And in the end they did their part to assist with keeping mystical creatures alive. There are five demon lords who signed the contract. One from each of the first two levels of the demonic realm, and three from the third level of the demonic realm.