Series in one sentence:
A super-hot and funny guy is somehow considered a loser by everyone.
Series in more sentences:
A boy who skipped more days of school than he attended discovers he is the son of Satan. After his adoptive father gets killed by the demon, he decides to follow the same path he and twin brother took; to become an exorcist, all with the purpose of killing Satan.
It's a strange thing to be rooting for someone who's associated with the devil, but it's hard not to like a funny guy. This series offers cool action scenes, like you would expect in an anime about demons, and does everything it can for you to like the main character. And even the side characters.
I appreciate that no one in this series is "just a bully" put there to be a barricade for the hero.
The only three things that disappointed me were the near-romance scenes that didn't go anywhere, Satan's lack of care for the children he had with the woman he, I think, loved, and the ending in general. After the big climax, there wasn't really a satisfying ending that tied it all together.