Hours passed as the monster tossed and turned on the bathroom floor, its fits tearing gouges in the walls from the fiend's claws and barbed tail. When the glowing red eyes finally opened again, the world shook in fear of the newly manifested demon... Or it would have if the priest hadn't performed a quick blessing on John before he left. Divine intercession, combined with the slain monster's blood carrying actually very little spiritual taint ensured that the world was in no immanent danger from a demonic overlord.
The demon that was once the human named John stood uneasily on his hooves, aware of the new weight swinging between his legs. He looked in the mirror and beheld his hell-spawned visage, the realization of what happened overcame him. John recoiled at his hideous new body, but he also slowly noticed that, while he was indeed a demon, his mind was intact. Unlike the fiend he valiantly fought, John was in complete control, there was no compulsion to consume the souls of unwitting mortals.
Despite his relief, no one fully escapes the corrupting influence of the Pit. John was dimly aware of his increased desires of the flesh. A small part of him, touched by the evil but countered by his own virtue and strength of will, would need to be fulfilled. But where the villain that had been Michelle slew her victims, John would leave them alive. Alive, but likely not completely human.
John knew he had no place in normal society anymore. Night had fallen while he was out. He walked out the front door, spread his wings, and awkwardly took to the sky.