Stuck between three fronts in the biblical apocalypse.

You are a former INF-BD soldier. A type of genetically modified soldier, specifically designed for combat against demons, when the first invasion started. Your heart has been replaced with an infernal catalysator, a small machine that repairs and permanently enhances your body, when your skin touches demonic energy, mostly through blood. Your kind has been discarded by UNTAG, because your combat efficiency was deemed to be lacking compared to their new generation of combat drones and the final nail in the coffin was the angelic invasion, whose forces were barely affected by your kinds "gimmick". Now you have to survive in the ruined lands around the few UNTAG mega cities. Doomed to be with your kind, because the average human survivor thinks of you as a demon, due to your grotesque combat-afflicted mutations.