Cruel Dragon Arc

Landing eighteenth in the overall run and third within the Neo Heroes Saga, this brief installment follows Saitama into a hidden conflict between two secret orders. It uses the encounter to expand the setting with sealing magic and cult mythology while keeping its trademark punchline: an ancient terror ends the moment Saitama swings.

Saitama blunders into a clash between the Saints and a cult called Deathbone, ending it by flattening Rangor, one of the Dragon Alliance's nine warriors serving the cult. Grateful, the Saints recount the legend of Cruel Dragon, a monstrous beast that once ravaged humanity before ancient soldiers bound it with nine sealing orbs. For eight centuries the order has protected those stones, since gathering all of them would break the seal, while Deathbone, convinced its members carry dragon blood, has schemed to revive the creature and wipe out mankind.

Tired of waiting, Saitama decides the simplest solution is to release the dragon at once and destroy it. He recruits a captured Deathbone follower to help him track down every stone, slips away from the pursuing Saints, and has the cultist perform the summoning ritual. Cruel Dragon awakens after ages of confinement, proclaims humanity's doom, and lunges, only for Saitama to obliterate it in a single effortless blow.

The reawakened legend dies as quickly as it returned, leaving the cultist stunned and the Saints elated. The episode broadens Saitama's grasp of his own world; later, gaming at his apartment with King, he admits that he assumed sealed relics and doomsday cults belonged only to fiction and confesses how much of reality still surprises him. The ritual's magic circle also confirms that genuine sorcery exists within the setting.