In ancient Disboard, Riku is an angry, young warrior intent on saving humanity from the warring Exceed, the sixteen sentient species, fighting to establish the "One True God" amongst the Old Deus. In a lawless land, humanity's lack of magic and weak bodies have made them easy targets for the other Exceed, leaving the humans on the brink of extinction. One day, however, hope returns to humanity when Riku finds a power...