Ao no Exorcist, High School DxD Recommendations
Both are typical highschool shounen shows with supernatural (aka devil/demon) elements, with the main difference being that Ao no Exorcist doesn't have the enormous amount of fan service.
In both shows the loser/outcast/main protagonist gets involved with these supernatural elements and has to fight and train with all his might to win the inevitable battle at the end to safe the ones he loves.
Typical, but very enjoyable.
Both shows have a strong base in the battle taking place between heaven and hell. They each have good action and a simple yet enjoyable story. Don't go in expecting anything to deep, but it will be a fun watch nonetheless.
Both are about a boy who one day finds out about how his world has its secrets and by secrets they find out that demons are real and they're have to fight and kill the rouge ones.In Ao no Exorcist,the MC chooses to fight them because he feels he needs to prove that his bad bloodline doesn't make him a bad person while in Highschool DxD the MC is revived by a demon and has no choice in the matter so he has to learn to fight in order to survive.Ao No Exorcist is more of a Shounen while Highschool DxD is a Ecchi/romance/action