Books like Slaying Monsters for the Feeble

I'm bound to a demon.For my entire life, I avoided magic at all costs. Now, I'm responsible for a demon who wields magic more powerful than the toughest mage or sorcerer.Demons are evil.That's what my textbooks say. That's what I see. He's ruthless, he's temperamental, he's cold. But he protects me without fail. I wonder if he's hiding a heart behind his hostility.My demon is a monster.Whether he's heartless or not, my contract with him is illegal and beyond dangerous. Together, we must find a way to return him to his own world before anyone discovers our secret. If that wasn't bad enough, I've come to realize something else:My demon isn't the only monster I should be worried about.