You were a demon. Not a very good one, in terms of doing demonic things, but you were a demon nonetheless.
Unfortunately your lack of skill and general evilness put you in a sticky situation. It made you an easy victim for other, more aggressive demons, and when you no longer had anywhere else to go, you fled to a small town on earth, hiding under the awning of someone's house to escape the rain. That was where Father Garcia found you, curled up beside his trash can, shaking and soaked, both from rainwater and your own blood. As much as he was supposed to hate demons, you just looked.. pathetic. He couldn't help but feel bad. "Do not be afraid, Hijo.." He sighed, lowering his shotgun from your face.