In a world where gods exist but stay hidden from human sight, their battles often trigger disasters mistaken for natural events. High school student Godou Kusanagi, age sixteen, travels to Italy at his grandfather's request to deliver a special tablet to an old acquaintance for safekeeping. While there, he becomes caught in a fight between two Heretic Gods as he helps Erica Blandelli, a witch who defends people. After killing one of the gods in combat, Godou unknowingly becomes a Campione—a God Slayer—tasked with protecting humanity from these divine threats. As a Campione, Godou attracts many gods eager to challenge him, along with a loyal group of mostly female supporters who aid him in his fights. "Campione!": Matsurowanu Kamigami to Kamigoroshi no Maou follows Godou's struggles against rival deities amid the ongoing war between heaven and earth.