Levi Kekken, the "Demon Slayer," is a legendary warrior blessed by the Overseers with divine power. His unmatched skills make him humanity’s greatest protector against demons. Despite his abilities, Levi struggles with personal loss, especially after meeting Marcus Devi, a vengeful exorcist seeking redemption for the deaths of his family. Together, they uncover dark truths aboard the Nightship, a vessel that may hold the key to defeating Catastrophe and the demons that plague their world.