Kai grew up idolizing Ginta, the hero of the War Games fought six years earlier in MAR Heaven. Taken in by an ARM smith after his parents died, Kai is attacked by a bandit while out on an errand and stumbles onto Babbo, a living ARM left dormant since the war. His own latent magic wakes Babbo, and Babbo's waking sends the mass-produced fake ARMs across the world out of control. Determined to live up to Ginta's legacy, Kai sets out to find his place among MAR Heaven's warriors.