Paradise Group Arc

Third in the series and the final leg of the Introduction Saga, this arc introduces three lasting elements at once. It brings in the ninja Speed-o'-Sound Sonic, first hints at the covert group known as the Organization, and sets up the wider hero establishment that Saitama and Genos will soon join. The plot spins out of a militant cell whose members happen to share Saitama's bald look.

Hammerhead rallies his followers around the notion that labor should belong only to those who enjoy it, and they resolve to make their statement by wrecking the mansion of the wealthy Zeniru. Mumen Rider tries to block their advance and comes up short. Watching the news, Saitama notices that every terrorist is shaved smooth like himself, and he sets out to end the matter so nobody confuses him with the group.

Zeniru's hired shinobi, Speed-o'-Sound Sonic, cuts through the cell and leaves only Hammerhead alive after a short exchange, though the leader manages to slip away. Deeper in the woods, Hammerhead runs headlong into Saitama, whose counterpunch shatters his armor. Saitama simply tells him to behave and lets him go. Moments later a pair from the Organization knock the fleeing terrorist down and ridicule him for having stolen the suits.

Sonic catches up and demands to know where Hammerhead went, then strikes at Saitama twice, both blows stopped cold. Saitama insists he is a hero rather than one of the bald militants, but the ninja stays unconvinced and shows off his blinding speed. Saitama keeps pace with every movement, and Sonic's own momentum drives his groin straight onto Saitama's fist. Humiliated, he retreats while declaring Saitama his eternal rival. Back home, Genos tells Saitama about the National Super Hero Registry, and the two decide to sign up.

Speed-o'-Sound Sonic makes his debut and, stung by his loss, appoints himself Saitama's rival. The Organization steps into view for the first time. Beaten by both Saitama and Sonic and nearly finished off by the Organization's agents, Hammerhead resolves to find honest work. The Hero Association and its ranks of heroes also enter the picture, and to earn recognition for what they do, Genos and Saitama choose to enroll.