Paradise Group Arc

The Paradise Group Arc is the third arc of the series, and the third and final arc of the Introduction Saga.

Plot
The leader of the Paradise Group, Hammerhead gives out a speech about how to work sucks and that only those who want to work should have to. When one of his subordinates mentions that no one is listening to him, Hammerhead gets angry and says to show them how serious they are, they will level the home of the multi-millionaire Zeniru. They get to a skyscraper and level it with one punch using stolen battle suits. One of Hammerhead's henchmen then reveals that they destroyed the wrong building and that Zeniru's mansion is further down the road. The group is about to head on towards Zeniru's mansion when the hero Mumen Rider shows up to stop them. However, he is quickly defeated.

The scene shifts to Saitama waking up rather dramatically from a dream involving snotty fingers. He turns on his television to see a report mentioning Hammerhead and the activities of the Paradise Group and begins to brush his teeth, ignoring the report until they mention that Hammerhead and his group are all bald and that citizens should watch out for bald people on the streets, at which point, Saitama gets very serious and rushes out to stop the group. As Hammerhead and his posse run rampant through the streets to get to Zeniru's mansion, Zeniru prepares to leave his mansion in preparation for the terrorists to arrive when his bodyguard Speed-o'-Sound Sonic appears in the window of his room saying that he will take care of the terrorists. The Paradise Group finally arrives at the grounds of Zeniru's mansion and begins to head through the property when Hammerhead stops them partway up the path. Sonic then appears in front of the group and threatens them all with death. Meanwhile, in his search for the Paradise Group, Saitama is getting mistaken for one of them and is getting rather frustrated.

Hammerhead sends his men to attack Speed-o'-Sound Sonic, and has to watch as they are all decapitated by Sonic, narrowly avoiding being killed himself. He then smashes the ground causing a massive shock wave, which ultimately does nothing to Sonic who then taunts him from a nearby tree. Knowing where Sonic is now, Hammerhead throws a large boulder at Sonic who dodges easily, the boulder continuing on until it smashes the roof of Zeniru's skyscraper. As Sonic lands on the ground after dodging the boulder he narrowly avoids a second boulder aimed at where he was to land. He looks up and sees several more boulders flying at him and dodges them all. Hammerhead then shows up, pushing through several trees, and taunts Sonic. Sonic then notices that all the boulders have "conveniently" made a direct path from Sonic to Hammerhead. Hammerhead lifts another rock and taunts Sonic again, so Sonic gets in an attack stance and rushes forward. Hammerhead drops the rock and picks up and smashes a tree down onto the path he'd made, but is then hit in the back of the head with a kunai by Sonic who'd managed to get behind him. Sonic takes out his phone and calls Zeniru to confirm Hammerheads death, but looks back and sees that Hammerhead is gone. Hammerhead, managing to survive thanks to his thick skull, runs away through the woods until he comes upon Saitama.

Saitama, looking for the Paradise Group had ended up in the woods outside Zeniru's mansion, when he comes upon Hammerhead. Hammerhead stops in front of Saitama, who then challenges him to a fight. Hammerhead throws a punch and smashes Saitama in the face, but it hardly even moved him and only left him with a mildly perplexed look on his face. Saitama expresses his disappointment in Hammerheads strength. This enrages Hammerhead who then puts his suit on full power and uses his "windmill attack," which reminds Saitama of how he used to fight as a child. Saitama then reaches out and easily stops Hammerheads attack and then punches him in the stomach, causing his suit to shatter. Hammerhead then runs off in the nude, promising to not do anything bad anymore.

At that point, Speed-o'-Sound Sonic arrives and asks where Hammerhead went. Sonic then throws a kunai at Saitama who catches it and then attempts to stab Saitama who stops him by grabbing the blade and breaking it. Saitama attempts to explain that he isn't a member of The Paradise Group but is instead a superhero, but Sonic doesn't believe him. Sonic then notes that the problem now isn't who Saitama is, but instead the fact that Saitama had managed to block two of his attacks. Sonic then challenges Saitama, stating that his pride won't allow him to lose, but Saitama then calls him out on the fact that he just wants to try out techniques on him and that he could tell by the childlike smile on his face. The scene then shifts to Hammerhead, who is being beaten up by two robots. The robots berate him for stealing the battle suits from "The Organization" and then leave him for dead.

Speed-o'-Sound Sonic starts the fight with Saitama by showing off his speed, by running and jumping at tremendous speeds around Saitama. He begins to goad Saitama about his speed until Saitama whips his head around to look at Sonic, asking if he could leave. This surprises Sonic who then flips and attempts to kick Saitama, but instead runs his crotch into Saitama's outstretched fist. Several moments later, Sonic stands in front of Saitama, practically crossing his legs in pain, and declares him his rival.

Some time later, Saitama is back in his apartment, talking to Genos about the incident with Saitama expressing his disappointment that Sonic hadn't heard of him, and his general lack of fame. Genos then tells Saitama about The National Super Hero Registry, something that if someone is not a part of, they won't be recognized as a hero. Saitama had never heard of this before, because it was founded after he became a hero, so the two decide to register themselves.

Story Impact

 * Speed-o'-Sound Sonic is introduced and after losing to Saitama, declares himself Saitama's rival.
 * The Organization is introduced.
 * After being defeated by Saitama and Sonic and nearly being killed by members of the Organization, Hammerhead decides to get a job.
 * The Hero Association and heroes are introduced.
 * To receive credit for their work, Genos and Saitama decide to join the Hero Association.