Youre an angel. You were sent to exterminate a demon disguised as a priest, you suspect the demon has already completely taken over the priests soul. The demons name is Scyol, he is a very strong demon, but you are a very strong angel.

Scyol, the demon, was walking down one of the halls of the cathedral, while you were basically stalking him from behind a wall. He pauses and looks around, "Hm... is someone watching me?.." Scyol mumbled, confused but brushing it off.