One punch-man Original Webcomic is a webcomic, originally created by ONE about the the adventures of the 'average' hero Saitama. This is the original series of the manga One punch-man thus, is where it gets most of its source at.
After the introduction of Saitama defeating Vaccine Man and Beefcake, Saitama's past is shown, which he trained so hard to achieve his superhuman strength. Along the way, he battles mysterious beings and beats them with a single punch. However, he lost all of his hair, claiming that it's because of his too much training.
After taking up arms against the Paradise Group led by Hammerhead, Saitama meets Speed of Sound Sonic who at that time is working as Mr. Monier's bodyguard. Sonic declares Saitama as his rival after his defeat.
Eventually, the lack of fame despite his efforts started to be a problem for Saitama and Genos suggests that he register as a hero in the Heroes Association. Saitama asks Genos to register with him in exchange of accepting him as his disciple, which Genos agrees. Saitama and Genos join the Heroes Association, with Saitama placing low in the ranking due to his awful score on the written exam. Saitama and Genos begin their lives as registered heroes, with Saitama struggling to maintain his position as a hero due to not reporting any work to the Association. After a run-in with Speed of Sound Sonic, he incapacitates him and reports it to the Association, who lock Sonic in prison.
After defeating Kombu Infinity, Saitama take a break at home while Genos is called to a meeting among S-Class heroes. The top heroes are called to arms to defend against an impending meteor impact. In the end, he, Bang, and Metal Knight are useless against the huge meteor, resulting in Saitama stepping forward to destroy it. Due to him having been in proximity of S-Class heroes, he receives only a portion of the credit, and other heroes begin to dislike him due to thinking that he uses the work of others to ascend in rank.
The Sea monsters emerge, led by the Sea King and wreaked havoc on J-City. Sea King managed to take down Stinger and Lightning Max. Speed of Sound Sonic, with the help of S-Class hero, Pri-Pri-Prisoner, escape prison and head out to fight the Sea King. Everyone that goes against him is defeated, but Sonic managed to escape. Genos and Saitama go despite the long distance from J-City. License-less Rider also go on his own, despite the fact that he stand no chance. Upon arriving at J-City, Genos meets a naked Sonic and asked him who he was. Sonic simply warned him about the Sea King and leaves. Eventually, Genos located the Sea King who just took down four heroes and attempts to stop him from destroying the shelter with civilians inside. He put up a fight and managed to trade blows with the Sea King until he is defeated when he used himself to shield a girl from the Sea King's corrosive saliva. License-less Rider falls in a futile but valiant attempt to stop the Sea King but is caught by Saitama, who proceeds to kill the Sea King with a single punch. The civilians, initially shocked and in awe of Saitama's power, are once again turned against him when he states that he took credit from the real heroes again in order to maintain the heroes' image.
With the consent of Genos and Bang, Saitama joined the S-Class heroes in a meeting when the Dark Matter Thieves attacked and destroyed A-City. Saitama enters the massive ship while the S-Class heroes partake in battle against Melzalgald, one of the three strongest underlings to Lord Boros. Saitama begins tearing the ship apart from the inside, taking down Gloryverse and Geluganshp before reaching Lord Boros and initiate a battle with him. After a long battle, Saitama becomes jaded with the fight and goads Boros into unleashing his strongest attack, which Saitama blows away with his Serious Strike, the force which mortally injures Boros, who states that Saitama is way too strong before dying.
Saitama becomes friends with King shortly after when the former realizes that the latter is not as strong as he is made out to be, but does not mind. During this time, many villains and outlaws are called to the Heroes Association HQ to be asked to join together to protect the Earth from future threats. Among them is Garou, Bang's former top disciple, who claims that he will become the ultimate threat, and proceeds to slay all the villains and heroes present, beginning a hero hunt.
At some point, Blizzard, Eyelashes and Mountain Ape decided to invite Saitama into joining the Blizzard Group. However, his refusal urged them to take him down but Eyelashes and Mountain Ape were easily knocked out. Blizzard attacks Saitama with her psychic powers but doesn't seem to hurt him, and even patronizes her about being a hero. At the same time, Sonic wants to challenge Saitama again, but is confronted by Genos. They begin their own battle and Genos's attack accidentally caught Blizzard with the impact. Genos apologizes for the mess he made and recognizes Blizzard as the #1 in B-Class. He misinterprets her current position as a failed attempt of taking down Saitama and claimed himself as a disciple of the latter.
Sonic continues his attack with an exploding shuriken on Genos but was unharmed. Seeing his disadvantage in speed, he decided to increase it and attacks Sonic, this time cutting off his hair. Blizzard estimates Sonic's abilities as on par with an S-Class Hero. To settle things and prevent more damage to his place, Saitama finally steps up and smacks down Genos to face Sonic. Saitama easily finishes the fight, with Sonic swearing to defeat him again. On the other hand Blizzard was totally speechless for everything that happened and even more shocked to find that Saitama is friends with King. Saitama apologizes for accidentally overwriting King's saved game data. She explained that she wanted to secure her position as 1st in B-Class because it was her first time being on top. She added that she has no chance of being 1st in A-Class because of Handsomely Masked Sweet Mask and expresses her inferiority complex towards her older sister, Tornado.
After a long hunt, Garou is hunted by Bang and his older brother, Bomb, who beat him mercilessly before they are attacked and incapacitated by a group of monsters from the Monsters Association, who take Garou with them. They state to Garou that they will keep him if he kills a human. He failed the test by helping an ugly child that was being bullied. The monsters attack him but failed to kill him, only knocking him unconscious.
The Heroes Association becomes aware of the Monsters Association HQ in Z-City, and began an infiltration, composed of S-Class heroes at the same time as Garou. The battles between heroes and monster began, with many heroes defeated by Dragon level monsters. Tornado reaches the leader and rips the entire base out of the ground. She begins the battle against the Dragon level monsters, but is attacked from behind by their leader, weakening her. On the other hand, Saitama who was disturbed by the noises, goes in his own to see what was happening and meets Lightspeed Flash who had mistaken him as an enemy. Together, they find their way to reach the top and help the others. Genos, King and Blizzard also went their own way to help. Upon reaching the top, Blizzard battles and defeats the leader of the Monster Association who is revealed to be an acquaintance of her and also a psychic. After that, Garou appears, having become immensely powerful from his many battles, and evolved into a borderline monster himself. She was not harmed, but was left in total fear. Garou incapacitates multiple S-Class heroes and monsters, then taunts the heroes who are unable to fight, threatening that he will kill the child he had once saved from being bullied.
At this point, Saitama approaches him with a complaint that he is being a disruptive neighbor. He states that he is going to beat some sense into Garou, who attacks with the thought that Saitama cannot withstand the attack. The result is that he is hit with a punch that sends him skipping across the ground. Garou utilizes his martial arts prowess to briefly appear to be overtaking Saitama, but Saitama grows bored and tells Garou to truly fight all out, demonstrating how serious he himself can be by flipping the entire Monsters Association HQ once again.
In the debris, Garou becomes disoriented and is beaten badly by Saitama. Upon landing on the ground, he becomes frustrated and more desperate, trying to damage Saitama in any way that he can. After failing and takes another powerful hit, he evolves into a complete monster and attacks Saitama, only to be defeated in one punch, resulting in another evolution that is swiftly dispatched as well.
After a long spiel about his philosophy, Garou demands that Saitama explain why he is a hero. Saitama's simple answer irritates him into yelling more, and Saitama shatters the remaining monster mutation left on Garou in frustration. He states that Garou had an ideal image of a hero in his mind the entire time, and suggests that Garou wanted to be a hero all along, but chooes to become a monster that simply had to kill every hero and unite the world against him.
The heroes attempt to kill Garou, but Saitama stalls them and Bang attempts to punish Garou. After the child Garou saved intervenes, Garou becomes filled with a desire to live and flees the scene.
Shortly after, two heroes went on to give their new neighbor a visit to introduce themselves, but ended up being intimidated after King faces them. King wonders where Saitama went.
Main Article: Characters
The Manga adaptation of One Punch-Man is illustrated by Yusuke Murata and follows the adventures of Saitama. While being almost exactly the same series in terms of content there are slight variations and the artwork is a much higher quality. The Manga is published by Sheuisha's Young Jump Next and has several volumes to it's name.