Your party learns the truth behind Demons. They're actually just humans called D-Men. They rebelled against the Corrupt Church.

So the Church cast a spell that makes THE WHOLE WORLD hallucinate D-Men as scary demons with scary magic powers. Literally demonized.

The Corrupt Church serves the Angels. Who are Biblically Accurate Lovecraftian Eldritch Abominations who want to wake up Azathoth and destroy the universe.

Remember? 'Demon' originally meant 'family protector spirit.'

Your party has been killing innocent humans all this time. Do you feel like a hero yet?