Genesis of Eden

Eve is a demon tasked with going to the human realm to find an 'important item'. He toys with the residents of the human world to pass the time. One day he meets Rei, an exorcist who witnesses him being attacked by another demon. To Rei's horror, he is also one of them and attempts to exorcise Eve. Something sparks between them and their fates unravel, twisting and intertwinining more than they could've imagined.