Demonika
Clover has wanted to learn magic since he was a little boy, but his father absolutely forbids it. Then a chance meeting with a young girl gives Clover an opportunity to learn, and he takes it with little care for the consequences. It's only years later that he learns the young girl is a demon, and being her apprentice isn't all fancy spells and neat tricks.
Oblivion
Hell is at war, and the demon Belial has been tasked with retrieving several precious artifacts stolen by human hunters. To get them back, he must pose as a hunter and earn the trust of Ian Oakley, the son of one of the most famous demon hunters there is. The plan works well enough, but Belial begins to have second thoughts when he realizes just how powerful- and useful- the hunters could be.