Akuma wa Rosario ni Kiss wa Suru

Yukihiko, a boy who possesses a "sacrificial soul," a soul tempting to demons, has seen supernatural beings ever since he was a child. Yukihiko thinks they are ghosts, but in reality they are demons. People haunted by demons are are prone to misfortune and death. Yukihiko wants a peaceful life with friends and a girlfriend, but when he is around other people, he always seems to get them into trouble and make them unhappy. One day, while worrying about whether he could somehow get rid of those demons, Yukihiko encounters an especially fearsome demon. He escapes and meets a nun named Alicia inside a church, where he makes a contract with her to exterminate the demons that haunt him. However, Alicia's true identity is that of a "demon" herself, one who plans to become the Demon Lord.

(Source: Kadokawa, translated)