Diablo, the former Demon King, unexpectedly finds himself mistaken for a deity after meeting High Priest Lumachina Weselia. Together with his companions, Diablo embarks on a mission to purify the corrupted Church. Lumachina's belief in him as God leads Diablo to protect her as they search for the revered paladin, Batutta. Joined by Horn the grasswalker and Rose the Magmatic Maid, Diablo, Rem, Shera, and Lumachina face the challenge of fulfilling Lumachina's desires. Can Diablo, a Demon Lord from a different realm, truly embody the divine role thrust upon him?