What would you do if you found out your dad was Satan? In the manga Blue Exorcist by Kazue Kato, when Rin Okumura finds out dear old dad is the Ultimate Evil, Rin swears to destroy him. And so a half-demon secretly enters an academy for exorcists to train up to fight and defeat Satan.
This would be a straightforward action-adventure, except the head of the academy may not be human himself and he seems to be plotting something. And Rin's twin brother turns out to have a few secrets of his own! And there's this magic sword and some mysterious classmates and other demons keep popping up. Rin's suddenly a very busy half-demon.
I love the way the demons are drawn here. If you come into this expecting echoes of Catholicism, try again. For the Japanese, devils and demons are a little bit more complex and a little less black and white. Mind you, some of the demons in this serie are flat-out evil. But this series has much more to do with Japanese folklore and ghost stories than The Exorcist.