Saitama

Saitama (サイタマ, Saitama) is the main protagonist of OnePunch-Man and the most powerful hero alive. Saitama faces a self-imposed existential crisis, as he is now too powerful to gain any thrill from his deeds.

He registered with the Hero Association as a C-Class and eventually made a big leap to become a B-Class Superhero and is tasked to defend Z-City against Mysterious Beings. Under the Hero Association, he is given the name Caped Baldy (ハゲマント, Hagemanto).

Appearance
Saitama is a bald, ordinary looking man with a thin, but well-built physique and of average height and weight. He claims to have lost all of his hair suddenly and prematurely as a result of the toll taken on his body by his intense hero training. Three years before the story line, Saitama had spiky, black hair and brown eyes that are usually represented by dots.

Saitama is usually deliberately drawn in a simpler style than all the other characters, with an elliptical shaped head and only a simple mouth and eyes. When drawn in a more serious style with more detail, Saitama is revealed to have sharp features, dangerous looking eyes, and a chiseled musculature. Even his posture undergoes a metamorphosis, with a slack posture and sloping elbows when lax, while possessing a straightened posture and squared shoulders when serious. His costume is a plain yellow jumpsuit with a short zipper at the collar and a belt. The costume is finished out by a red ensemble of boots, gloves and a white or red cape.

Personality
For a superhero, Saitama is thought to be quite indifferent. Even the mightiest foes pose no challenge to him, so he doesn't take his hero work very seriously and beats monsters like swatting insects. Since his superhero work has begun to bore him, he is constantly searching for an opponent that can challenge him. The lack of any such opponents has led him to suffer from an existential crisis, and he claims that his ability to feel any and all emotions has dulled considerably. He stated that he just became a hero because it was his dream and for self-satisfaction and before becoming one, used to suffer from anxiety issues. Despite his boredom, Saitama does not ignore crime, as in his own words (having displayed a lack of understanding at the disaster level system), "If the heroes run and hide, who will stay and fight?".

The combination of his attitude, unstoppable strength, and distinctively simple and 'unimpressive' appearance often cause his battles to become anticlimactic. Saitama will usually allow his opponents rant about their motives and power up into their strongest forms before obliterating them with a single punch. However if they talk too much he will either interrupt them or just punch them.

A running gag about Saitama is his inability to remember people's faces and names, seen when he forgot Sonic's name and could not remember who Tanktop Tiger was. Because of this, he always ends up pronouncing their names incorrectly.

As of some special chapter during his time participating a costume contest, appearance doesn't matter to him, the only thing matters to him are his abilities and his desire to be a the super hero he's been training for. That being said, he does care about his cleanliness, as the only thing he ever really complains about is how he gets dirt on his clothes or blood on his gloves. Though he doesn't care about appearances, he has shown dislike towards his hero name, Caped Baldy. Thus even after receiving it, he always refers to himself as Saitama.

Saitama has been shown to be very humble, as he purposefully let the masses turn against him, for the sake of the defeated heroes to be given credit for their efforts; claiming that they had weakened the Sea King before his arrival. He did the same for the police in the Special Chapter, dressing as one of them and killed a monster, though he would had gain much fame had he revealed who he actually was. He also didn't mind that King took credit for all of his achievements.

Another surprising thing about Saitama is that he is surprisingly tactful and insightful, being well able to discern situations and character traits from the people and environment around him fairly easily. Having picked up a number of hints to Sonic's own persona on their first meeting and when two tank top heroes jealously plotted to ruin him after the meteor event that there were irate and self-serving hero types like them, as well as discerning Fubuki's forced offer of submission or destruction just before his crackdown on how the hero world really works than how it is currently run.

Saitama has been shown to show remorse to his enemies before, particularly ones who can give him an actual fight and don't go down in one hit. One such example of this being Boros, to whom, in order to give an exciting fight to (seeing as he could relate to having similar amounts of power), though in the end, still couldn't draw out Saitama's full power.

Saitama does not actually care if people insult him and he usually ignores them and says that they need a hobby; the only insult that could at the very least get a what could be called reaction out of him is when someone mentions his bald head. He also shows a measure of concern when it comes to bargains, as seen when he fought Carnage Kabuto, when he was more shocked upon the realization that he was going to miss a bargain sale, rather than his opponent, who had undergone a transformation and was whacking him around. Despite his general indifference to most things, Saitama was genuinely shocked to when he realized that no one actually knew of him, despite his achievements (although this could be attributed to the fact that he never stuck around after saving the day).

Saitama shows impressive restrain with his power, considering that with his physical ability, he is capable of splitting the sky, or jumping from the moon to earth easily. He manages to beat nearly all of his opponents with a single punch, though occasionally causes more devastation than necessary. While he has no problem killing monsters, Saitama has yet to be seen killing another human, and uses only enough strength to knock them out.

History
Little is known about Saitama's past, but it is known that he lives in his apartment by himself. As a child, according to Saitama, he used to watch superhero shows many times, and wishes that he wants to be like those heroes too someday.

Middle School Year
In his second school day of his freshman year in middle school, Saitama is seen reading a health and PE manual, but did not hear from the other students about what happened to the freshman who called himself "The Bicycle Commuter" yesterday, after two third-year bullies beat him up pretty badly.

After school on a rainy day at 4 o'clock, Saitama is watching a news about the ongoing monster incident in Z-City, news of which happened nine months ago. Saitama drifted off to sleep but forgot to do his homework. As a result, he is called by his homeroom teacher to the teacher's room, despite suggesting that he could do both days' homework that night.

While going to the teacher's room, he is interrupted by the same two third year bullies from yesterday, and threatened to hand over his wallet, but Saitama told them he doesn't have one and prepares to fight them instead. However, Saitama is still too weak to defend himself from the bullies and his 200 yen was stolen by them. Shortly after, Piggy Bancon attacks the bullies and takes Saitama's stolen money from them, Saitama soon heard that one bully's reason in threatening the freshmen to steal their money was to feed his little brother his lunches and Saitama goes chasing after the pig monster to get his money back, but due to his lack of strength, is unable to retrieve his 200 yen. After the monster is destroyed by the police and special unit forces, Saitama decides to return to school and see his homeroom teacher.

Saitama is then scolded by his homeroom teacher, while trying to tell what happened to himself back before going to the teacher's room, though the teacher thinks Saitama is bluffing. While going home, Saitama becomes very disappointed in himself for being weak and losing many times, and starts to think about himself and his future.

Adult Year, First Hero Act
More than three years prior to the start of the story line, Saitama was an unemployed man on a job hunt. One day, after yet another failed interview, a nihilistic-feeling Saitama was wandering the streets and encountered Crabrante. Saitama's total apathy toward the situation impresses Crabrante, who claims to share a similar outlook, prompting him to spare Saitama and move on. Crabrante tells him that his real prey is a child with a cleft chin anyway.

Walking on, Saitama spots the child Crabrante was talking about. He decides that he doesn't want anything to do with the matter but after Crabrante suddenly arrives, Saitama impulsively saves the child from Crabrante's attack. He urges the child to run away and demands to know why Crabrante wants the boy dead. While Crabrante explains the prank the boy pulled on him, Saitama chuckles and notes aloud how the monster resembles one from an anime Saitama watched in his youth. This enrages Crabrante, who pummels Saitama even after the latter resolves to live out his childhood dream of being a superhero by fighting back. As Crabrante turns from the apparently defeated Saitama to finish the cleft-chinned boy, Saitama lassos one of his eye stalks with the loop of his removed tie and tears it out. The monster is defeated and the child saved. Unknown to him, the child confronted his grandfather for the creation of the Hero Association in Saitama's honor for saving his grandchild from the monster's crime.

Resolving after this encounter to become a mighty superhero, Saitama started a daily training schedule which consisted of 100 push-ups, 100 sit-ups and 100 squats along with running 10 km every single day. He ate three meals a day, but only a banana as breakfast and also didn't use the AC, to strengthen his mental resistance. These daily activities were extremely tough and caused his body excruciating pain; muscle aches and internal bleeding. However, Saitama didn't give up and continued his training day after day.

Personification of a Light Pull Cord Attack
On Saitama's 300th day of training, his body had already felt the effect of working out too much. However But still, Saitama has shown signs of improvement, such as wrecking a car after saving a boy from an accident. At that time, the Personification Of A Light Pull Cord attacked the streets, looking for an opponent that would satisfy him.

The Personification punches cars and buildings as he keeps searching. To test the fruits of his labor, Saitama challenged the monster but was sent flying after a single punch. Filled with determination to overcome his limits, the monster punches Saitama again and is knocked down. However, Saitama quickly got up, spat out a tooth that had been bothering him because of a cavity.

Saitama then defeated the monster with a single punch before moving on with his workout.

King's Beginning
At some point in the first year and a half of Saitama's training, the Octopus Claw Man attacked an unspecified group of people. Saitama arrived and defeated the Octopus Claw Man, though sustained multiple injuries from the fight. After the fight, he consoled one flailing civilian who had suffered three scratches above his left eye from the mysterious being. When questioned about his injuries, Saitama shrugged it off, simply smiling at the thought that there was a special sale that day.

Magicicada Larva Attack
Some time between when Saitama started training and started to lose his hair, Z-City experienced a Mysterious Being attack by the 170,000-Year Magicicada Larva, prompting the citizenry to evacuate to the state-of-the-art Shelter Nr. 7. The three low-ranking heroes sent to defeat the Magicicada were defeated, but survived and managed to find some straggling evacuees on their way back to the shelter, among them being Saitama.

When Saitama discovers that he has been led to a shelter, he became upset, stating that he thought that following the heroes would lead him to the Mysterious Being. Saitama attempts to leave so he can find the Mysterious Being, but is restrained by the citizens, thinking he's become suicidal. The guards attempt to explain that the doors can't be opened while the disaster is still ongoing, but reassure the public that the shelter is able to withstand any sort of attack. While she praises the structure's perfection, Saitama confronts one guard again to ask where the bathroom is, only for her to reply that the 'perfect' shelter was nevertheless designed and built without bathrooms.

Saitama slowly becomes more and more distressed, as he doesn't know if his bladder can hold until the situation ends. After overhearing that two A-Class heroes were defeated by the beast, and that it will take three hours for a Hero Association squadron to arrive, Saitama can't take it anymore. He walks to a wall of the shelter and breaks a hole in it with a single punch before the stunned onlookers, and runs off stating that he's going to the convenience store. Just as he is about to reach the store to use the bathroom, the 170,000 Year Magicicada Larva appears in front of him, which he promptly kills.

One and a half years after he started training, he had lost his hair and become strong. He continued his training for another year and a half before starting his (initially amateur) superhero career.

Saitama Introduction Arc
Saitama first appears watching a news report on Vaccine Man attacking Z-City. Seeing the destruction, he remarks that he should be leaving.

Saitama appears at the scene just in time to save a young girl from being killed. The monster is angered and asks who Saitama is, and he replies that he is "just an average guy who serves as an average hero". After reluctantly listening to the monster's angry monologue and watching its transformation, Saitama kills it with an effortless punch. After this, he screams out in frustration at another easy victory; a pattern which will be repeated in future battles.

Some time after, Saitama hears about a Demon-level disaster emergency, stemming from the Brain and Brawn Brothers destruction of D-City. After finding the duo, Saitama leaps onto the monstrous Marugori's shoulder and tells him to put some pants on. Hukegao, Marugori's brother who is on his other shoulder, is shocked by Saitama's sudden appearance and orders his brother to swat him. However, Marugori absentmindedly swats at the wrong shoulder, instantly killing his brother. Enraged, Marugori grabs Saitama and throws him into the ground. Saitama is unaffected, but Marugori continues with a frenzied assault of massive stomps and punches, creating a large crater. Believing he has killed Saitama, Marugori moves away, only for the completely unfazed  Saitama to dash out of the crater and crumple the giant's face with a single punch. Saitama states that having an overwhelming power is boring as hell, as the dying Marugori topples over. Unfortunately, Saitama's blow causes him to fall on top of B-City and the town is destroyed.

House of Evolution Arc
Saitama later is shown lamenting his lot in life: how every fight ends with a single punch and goes on to compare all his battles to swatting insects. As if to illustrate the point to himself, he delivers a mighty swat to a mosquito that has landed on his hand, but when he lifts up his hand the mosquito flies away unharmed. After unsuccessfully swatting at it several more times, it flies off and Saitama is left in a rage. The mosquito is then shown to fly off to Mosquito Girl. Before this event, Saitama saw a news story about a mass mosquito outbreak that is headed towards Z-City, and plainly says; "Aww man, City Z's in their way.

When Mosquito Girl raids the city, Genos makes his first appearance and starts to fight her and performs well for a while, but then she begins absorbing all the blood gathered by her mosquitoes. Saitama suddenly comes running around a corner on to the battlefield, in pursuit of the mosquito he'd been trying to kill. At that moment, Mosquito Girl finishes her blood-fueled evolution and sends her mosquitoes crashing down on Saitama and Genos, the latter of whom obliterates them all with a gout of flame. When the smoke clears Saitama is standing there naked and only slightly singed, thanking Genos for killing the mosquitoes.

The newly empowered Mosquito Girl starts attacking Genos and tearing him apart with her claws. Just as the heavily damaged Genos is about to resort to self-destructing, Saitama suddenly slaps Mosquito Girl, sending her flying through a nearby building and into the sky. Dusting off his hands, Saitama states that he hates mosquitoes.

After witnessing Saitama's incredible power, Genos begs Saitama to make him his apprentice. At Saitama's house, Genos gives a long explanation of his past and motives, but Saitama is completely uninterested. Saitama agrees to take Genos on when he explains that he simply wants to be taught to become as strong as Saitama.

Meanwhile, the House of Evolution, having become interested in Saitama after he defeated their warrior Mosquito Girl, sends more of its creations to attempt to capture him. Kamakyuri arrives at Saitama's house first, crashing through the ceiling and immediately has his head punched off for the trouble. Saitama and Genos then go outside to meet the threat where they are confronted with Frog Man and Slugerous. Saitama promptly buries their heads in the ground complaining about how they made a hole in his ceiling. Suddenly, a hand emerges from the ground by Saitama's foot, grabbing his leg and dragging him underground, until only his head protrudes from the sidewalk. Genos begins to rush to Saitama's aid but is intercepted by Armored Gorilla. While Genos is fighting Armored Gorilla, Saitama is approached by Beast King.

Beast King congratulates Ground Dragon on incapacitating Saitama but notices that the distinctly un-terrified hero is falling asleep due to how pleasantly temperate he found it underground. Beast King starts to get angry and threatens to scratch Saitama's eyes out, at which point Saitama simply steps free out of the ground. Beast King then attacks Saitama, who easily avoids his claws and slicing air currents, one of which kills Frog Man and Slugerous. Beast King is enraged that none of his attacks are hitting and goes berserk, sending a flurry of attacks at Saitama, who dodges them all before striking back with a short combo of punches. The attack obliterates Beast King's entire upper body, prompting a terrified Ground Dragon to run away by digging underground, but Saitama appears in front of him through a hole of his own making and punches Ground Dragon through the earth and up into the sky. When Saitama gets back to the surface, he finds that Genos has defeated Armored Gorilla and is questioning him. After Saitama shows Armored Gorilla the remains of Beast King he tells them all they want to know.

Roughly four hours later, Saitama and Genos have climbed a forest path to arrive at the House of Evolution's base. Wasting no time, Genos destroys the above-ground portion of the base with an energy blast, surprising Saitama slightly with his ruthlessness. In the rubble they nonetheless find a metal door which leads to the basement. As they enter the subterranean portion of the lair, they are attacked by Carnage Kabuto, who discards his former 'master' Dr. Genus before embedding Genos into a wall and incapacitating him with a single, thunderous blow. Saitama is angered because Carnage Kabuto turned Genos into "modern art" and agrees to Carnage Kabuto's request for a fight.

The fight is about to start when Genos re-appears and attempts to fight Carnage Kabuto, but is beaten down again causing Saitama to step in to fight. Carnage Kabuto comments on how he can feel that Saitama is really strong, while Saitama tells him not to disappoint him, as he expects Carnage Kabuto to be the strongest being from the House.

Suddenly moving with tremendous speed, Carnage Kabuto appears behind Saitama and is about to strike him, but suddenly becomes extremely intimidated and leaps back, thinking to himself that if he had attacked at that moment he would have been killed. He explodes with rage and fear and orders Saitama to tell him how he got so strong. Saitama agrees to tell them and explains his method of 100 sit-ups, push-ups and squats and 10km of running every single day. Genos is outraged, stating that Saitama's strength would be totally impossible to achieve with that kind of routine strength training, while Carnage Kabuto is angered, thinking Saitama is mocking him.

Enraged, Carnage Kabuto enters "Carnage Mode" and states that he'll stay in this form and go on an uncontrolled rampage for a week, "until next Saturday". Carnage Kabuto then begins to pummel Saitama, sending him flying around the room. While this is going on, Saitama comes to the horrifying realization that if "Carnage Mode" lasts for a whole week ending on a Saturday, then it is in fact Saturday that day and thus he missed the "special sale day". Overcome with despair, he cries out and obliterates Carnage Kabuto with one punch.

Paradise Group Arc
Saitama is first seen waking up frantically from a dream involving someone pointing a snotty finger at him. Realizing it was just a dream, he then turns on the news and finds out that the criminal Hammerhead and his terrorist organization known as the Paradise Group, consisting entirely of bald, dangerous looking men have arrived and started wreaking havoc. The news warns everyone to avoid any bald men with a dangerous aura. This angers Saitama who states that this group will ruin his image as everyone will mistake him for a villain. He resolves to  destroy the Paradise Group to protect his image. Saitama heads out to search for the villains, and on his way many people end up mistaking him for members of the Paradise Group.

On his search for the Paradise Group, Saitama finds himself lost in a forest. Trying to find a path out, he is halted when Hammerhead, recently defeated by the powerful ninja Sonic, appears rushing towards him. Hammerhead mistakes Saitama for someone wanting to join up with the Paradise Group, and Saitama tells him that he actually came to destroy them. Hammerhead swiftly attacks Saitama with a vicious punch but Saitama is unfazed and unimpressed. Enraged, Hammerhead charges up to full power and executes his windmill attack. Upon seeing this Saitama notices it looks much like an 'attack' he used to perform as a kid and wonders if Hammerhead is similar to him. He then stops the attack with little effort and shatters Hammerhead's battle suit with a quick punch.

After making him promise to never do bad things again, Saitama allows Hammerhead to flee. Shortly after, Sonic arrives demanding to know where Hammerhead has gone. Saitama points in the direction that Hammerhead fled and says, "He went that way. Naked." Sonic then attacks Saitama, mistaking him for a member of the Paradise Group, with a shuriken thrown at lightning fast speeds. However Saitama effortlessly catches both the shuriken and Sonic's subsequent attack with a sword and then proceeds to break the sword in half. Saitama then frantically explains that he is not a member of the Paradise Group and asks Sonic whether or not he recognizes him as the man who has saved the world many times. When Sonic says, "Nope, don't know you" Saitama becomes severely disheartened. Sonic then proceeds to attack Saitama, stating that the real problem here is that Saitama was able to see two of Sonic's attacks and that his pride cannot allow for Saitama to live. Upon hearing this, Saitama accuses Sonic of being a liar stating that Sonic just wants to test his attacks on him, indicated by the childish (crazy) smile on Sonic's face.



After Sonic jumps around for quite some time, Saitama intercepts him and asks if he can go home now. Surprised, Sonic retaliates with a lightning fast kick, but Saitama attempts to interrupt his attack by placing his fist directly in the path of Sonic's genitals. However he accidentally moves his fist too far and taps Sonic's groin. Clearly in pain, Sonic swears that he will train day and night for their rematch and then flees. Later, Saitama is seen at his house going over the day's events with Genos. Saitama asks Genos to leave, stating that he is in shock due to a certain event that occurred that day. Genos, worried about anything that might shock Saitama, asks what it was and Saitama explains that he can't believe that Sonic had no idea who he was despite all his previous exploits. Genos then asks if Saitama was a registered superhero, which Saitama replies that he's not. Genos goes on to explain that anyone who hasn't registered with the Hero Association will never be recognized for their feats. Saitama resolves to become a licensed hero so he can achieve the fame he deserves. He asks Genos to register with him in exchange for formally accepting the latter as his disciple.

National Superhero Registry Arc


Saitama arrives at the 6th Official Superhero Certification Exam Center and begins a series of physical tests. Saitama does so well on physical tests that he awes the examiners and disheartens the up and coming superheroes from taking the tests altogether. Later in the waiting room, Saitama meets with Genos and the two discuss the easiness of the superhero qualification tests and state that there is no way they didn't pass. When the results of the tests arrive it is revealed that Saitama barely passed, having achieved a score of 71 when the passing is 70, and receives the C-class hero designation. Despite this, Saitama achieved a perfect score in all the physical tests and broke every record of the Superhero Association and the only reason his score was so low was because he did poorly on the written test.

Later, during a lecture from an A-Class hero, Sneck, Saitama is seen chewing bubble gum, seemingly bored. This angers Sneck and, along with hearing the news that Saitama could quickly surpass him, causes Sneck to ambush Saitama but is quickly defeated though non-lethally.

Sometime, Genos apparently requests a sparring match with Saitama. Saitama having earlier agreed to take Genos as his disciple officially, under the condition that Genos register as a superhero as well, accepts his challenge. The battle begins with Genos firing a massive energy attack which Saitama dodges with ease. Genos proceeds to to attack Saitama physically, but eventually discovers he was chasing an afterimage the whole time. After an extremely close-range energy attack in which Genos believe he finally landed a blow on Saitama. Saitama, having dodged the attack and poking Genos' face, declares himself the victor, but Genos reminds him that the match cannot end until one of them is unable to continue. Upon hearing this Saitama appears in front of Genos and delivers a devastating blow that stops inches before hitting Genos' face. Though unharmed, the landscape behind him is obliterated. Saitama and Genos then return home.

Five days later Saitama is seen lounging around his house reading a magazine. He notices Genos, carrying a huge backpack full of contents unknown, then requests to live with him. At first he declines, but after Genos tells him that he will pay him the rent Saitama allows Genos to stay with him.

Rumored Monster Arc
Genos later informs Saitama that all C-Class heroes who are inactive for a week are removed from the official registry. Saitama, realizing he only has two days remaining, sets out to find a villain, only to discover that Z-City is completely peaceful. Saitama decides he will check again the next day and returns home. Upon discovering that Z-City is peaceful for the second day in a row, he becomes greatly distressed. All of a sudden, a shuriken is thrown at Saitama, who catches it, and discovers that his would-be assailant is none other than Sonic.

Saitama tells Sonic that he is busy and begins to walk away but Sonic rushes to intercept him. Frustrated, Saitama bites Sonic's sword, shattering it in the blink of an eye. He explains again that he is busy and threatens that, if Sonic gets in his way again, he will punch him. At this time a woman from the crowd observes Saitama and states that he is a 'suspicious person'. Saitama, thinking that the woman was referring to Sonic, begins to lecture Sonic for being so violent. Then a C-Class hero, named Tanktop Tiger, explains that the woman was referring to him. Saitama explains that he is also a registered hero but Tiger states that he has no idea who Saitama is and thinks that he should leave as he is ruining the reputation of other heroes. Saitama becomes increasingly annoyed but, before he has a chance to attack, Sonic launches a surprise assault on Tiger, who is defeated instantly.

Sonic begins to wreak havoc on the surrounding civilians. During this chaos, Saitama saves a small boy's life by effortlessly moving a tree in place to intercept a falling car that would have killed the boy. Saitama, angered both by the fact that he can't find a bad guy to fight and that civilians are in danger, realizes that Sonic is now considered a bad guy and decides to retaliate. Saitama appears behind Sonic and dispatches him with a single swift chop. By defeating Sonic, he has saved himself from being removed as a registered superhero.Saitama, apparently returning home from shopping, happens upon a scene where a monster had just defeated two A-Class heroes in battle. Upon seeing the monster, Saitama remembers that he forgot to get kombu and notices that the monster appears to be made of it. Later, Saitama is seen cooking kombu that was apparently taken directly from the monster's body, leaving it totally naked. Genos states that Saitama wanted to eat kombu to see if it could make his hair grow back.

A New Wind Blows
After Tatsumaki leaves the fight against the Demonic Fan with Fubuki, Saitama shows up and notices that the Demonic Fan is not dead, but instead reforming itself. The young member of The Blizzard Group attempts to stop Saitama from going to attack the Mysterious Being, but Saitama goes anyways and easily destroys the Demonic Fan. He patronizes the coward hero and his words reached the latter. Inspired by Saitama, the hero left the group and started to train himself in order to get stronger.

Giant Meteor Arc


Saitama and Genos are relaxing in their apartment, and Genos tells Saitama that he's been promoted from C-Class, Rank 388 to Rank 342, and while he hasn't been raised from S-Class Rank 17, he's been ranked 6th in popularity. Genos then gets a call from The Hero Association and heads out.

Later, after Genos fails to destroy the Meteor, Saitama shows up and asks Bang to take care of Genos. He then launches himself at the Meteor and punches through it, causing it to break apart. Unfortunately the pieces of the Meteor then rain down on Z-City. Saitama then lands, looks around and says "Well, I guess that takes care of it," and walks off.

Three days later, Saitama and Genos are relaxing in their apartment again, watching a news report on how the Meteor fragments destroyed many buildings and businesses in the city. After learning that his rank had jumped up from C-Class, Rank 342 to Rank 5, Saitama gets excited and decides to go out for a walk around town. During his walk he gets called out by Tanktop Tiger, but Saitama doesn't remember who he is. Tanktop Tiger then declares that Saitama is a liar: that there is no way he would be able to destroy a Meteor on his own and that he merely took credit of the S-Class Heroes work. Saitama starts to defend himself but is cut-off by Tiger who calls out for his big brother, who then jumps in and introduces himself as Tanktop Black Hole.

Black Hole claims that he has a perfect punishment for a "lying cheater" like Saitama. He then, in a rather loud voice, starts accusing Saitama of destroying the town. The commotion starts to attract citizens who begin to gather around the scene. Black Hole continues to accuse Saitama of destroying the town on purpose and slowly, the crowd begins to turn on Saitama, shouting out threats and accusations along with Black Hole. Black Hole then accuses Saitama of wanting to destroy the citizens, just as he "destroyed" the town, and then challenges him to a fight. Tanktop Tiger then rushes forward to attack Saitama, but gets easily knocked away into a pile of rubble, much to Tanktop Black Hole's surprise. Tanktop Black Hole then jumps in and tries to crush Saitama with his grip. Saitama intercepts him and locks hands with Black Hole and squeezes, causing Black Hole to fall to his knees in pain and apologize for lying. Saitama then shouts to all the citizens that he did destroy the Meteor and that if anyone has a problem with him they should say it to his face. Some citizens move to accuse him of damage done to their property, but Saitama quickly shouts them down, telling them to blame it on the meteor, that he's not doing hero work because he wants to be admired by them but because it is something he wants to do, leaving his accusers stunned in silence.

Sea Monster Arc
On his way home, Saitama comes across a Seafolk about to attack a city, so he defeats it quickly. Some time later, Saitama is relaxing as Genos does dishes and explains that Saitama has advanced to the second rank of C-Class. He goes on to explain that once Saitama becomes rank 1, he can go up to B-Class. Genos then starts talking about how the top ranking C-Class hero hasn't left his position for around half a year,

which apparently is no match for the top ranking B-Class hero. Before Genos can finish talking about that though, he gets a call about an attack on J-City by more Seafolk. They turn on the news and watch part of a news report on the incident and decide to head out to help.

Some time between their leaving and their getting there, Saitama and Genos get separated. During his search for the Sea King, Saitama finds License-less Rider's cell phone lying in the street. Upon picking it up, the man on the other end of the line requests to know who he is speaking to and, despite Saitama only being listed as a C-Class hero, decides to disclose the location of the Sea King, apparently to finally determine just how strong Saitama is. Later, Saitama arrives at the shelter just in time to witness License-less Rider's defeat at the hands of the Sea King. He catches License-less Rider's unconscious body and tells him he fought well. He then observes the scene and is surprised to find that Genos is alive despite his grievous wounds. After remarking that he will quickly dispatch the Sea King, Saitama is attacked by the monster but he is noticeably unscathed. The Sea King declares his surprise that Saitama did not fall from his punch, but Saitama remarks that the Sea King's punch was simply too weak to hurt him. Meanwhile the spectators talk among themselves, telling each other that their situation has not changed at all with only a C-Class Rank 2 hero arriving. Sea King starts to tell Saitama that he, as the ruler of mother sea, stands at the very top of the pyramid of all living organisms on Earth. Saitama, however, interrupts him and tells him to hurry up and fight. The Sea King then quickly attempts to punch Saitama, only for Saitama to punch a hole in his body and destroy most of the street. As the Sea King falls, Genos is seen smiling (since only he knows of Saitama's true power), and all the spectators stare on in disbelief. Standing triumphant over the body of the Sea King, Saitama overhears the crowd of onlookers start to question the usefulness of the rest of the heroes who battled the Sea King. Not wanting the heroes' good reputation to be tarnished, Saitama remarks loudly that he got off lucky and that, if the other heroes hadn't weakened Sea King before he arrived on the scene, he wouldn't have stood a chance. To further the credibility of his ploy, Saitama plays on the rumors of his underhanded nature by stating that, because he's the one who dealt the finishing blow, he'll get all of the credit for the victory regardless of the other heroes valiant efforts. Saitama's plan proves successful and the people's faith in the other heroes that participated in the battle is restored, while Saitama, on the other hand, grows more hated in the eyes of the citizens. Internally, Saitama reflects on how dull the battle with the Sea King turned out to be.

Sometime after the battle with Sea King, Saitama and Genos receive a box via airdrop from the Hero Association, containing several letters addressed to the heroes themselves. Upon opening the five letters that were addressed to him, Saitama discovers that the first three contain nothing but hateful words accusing him of cowardice and cheating which angered Genos greatly but were disregarded by Saitama. The fourth letter contains a simple thank you message from an anonymous sender. The fifth letter turns out to be a letter directly from the Hero Association itself, notifying Saitama of his promotion to C-Class rank 1, and inviting him to Hero Association HQ in Z-City.

Upon arrival at the HQ, Saitama requests to know why he was summoned to the headquarters and suspects that they called him there to reprimand him for his actions. His hosts, however, insist that the circumstances for which he was invited are quite the contrary and they congratulate him on reaching C-Class Rank 1. They then go on to inquire as to whether or not Saitama will move up to B-Class or remain in C-Class. Saitama expresses his apathy on the subject but then goes on to state that he'd rather be B-Class due to the fact that he would no longer have to report his weekly activities to the Association. He also reflects internally that he can't remain in C-Class forever, especially considering that Genos is already an S-Class. Other officials of the Association watching from a separate room question even the legitimacy of his exam results, to which one suggests that they allow him into B-Class to test that legitimacy: should he hold his own his power would be unmistakable, otherwise he will be broken by the factions in B-Class, in particular the Blizzard Group. Finally, they consult Sweet Mask for the verdict; Sweet Mask, finding neither significance in promotions from C-Class to B-Class nor anything noteworthy in Saitama's impression, allows it.

Later on, Saitama is walking home from headquarters, examining the official document declaring him a B-Class Hero, when a delightful smell from a small oden shop draws him inside. Upon entering, Saitama orders an assorted oden and takes a seat at the counter where he is asked by another patron in the shop if he will have anything to drink with his oden. The patron then states that, if Saitama won't order a drink, then he will treat him to one. Upon observing this stranger, Saitama discovers it is none other than a bruised and battered License-less Rider. Saitama questions why License-less Rider would want to buy him a drink, to which License-less Rider states that, if for nothing else, it would be to celebrate Saitama's promotion to B-Class and also reveals himself to be the sender of the "Thank You" letter that Saitama received. Upon finally recognizing the man as License-less Rider, who he saved from the Sea King, Saitama accepts his offer and orders a mozuku.

Alien Conquerors Arc
At a later date, Saitama and Genos are watching as Silver Fang demonstrates one of his techniques to the duo. Upon being asked to attempt the technique, the pair express their disinterest in a non-destructive technique, eliciting an outburst from Silver Fang's only disciple. After being questioned on the whereabouts of the rest of his students, Silver Fang explains that a long time ago one of his students went out of control and defeated a good handful of the others causing most of them to leave the dojo; subsequently forcing Silver Fang to take it upon himself to take him down. After hearing this story, Saitama remarks that Silver Fang must be quite strong evoking yet another outburst from Silver Fang's student.

Shortly thereafter, a member of the Hero Association arrives and declares that all S-Class heroes are to report to HQ immediately to address a major crisis. Genos states that, since all S-Class are being convened, they might have need of Saitama's power and Saitama accompanies them to HQ where all but two of the S-Class have already arrived. The first S-Class hero to interact with Saitama is S-Class rank 4 Atomic Samurai who, even after hearing the praise of Saitama from Silver Fang, refuses to shake Saitama's hand; stating that he will only acknowledge those in the S-Class category. Saitama then hears a flurry of disapproving remarks at his presence at the meeting and looks over to discover the culprit is a very young girl who, to his surprise, happens to be the S-Class Rank 2 Tornado of Terror. Thinking she's just some cheeky kid Saitama blatantly ignores her and goes to sit down with the rest of the heroes, angering Tornado, who is unable to do anything about it other than complain. As most of the S-class heroes are conspiring with their own thoughts, Silver Fang asks what they been called here for. Tornado replies angrily that she doesn't know and they've kept her waiting for two hours. Saitama casually asks for some tea. Some time would pass before Saitama would rank up from 101 to 63.

After having heard of the great calamity foretold by Lady Shibabawa (who recently died due to choking on her own cough drops) Saitama found the opening to ask Puri-Puri Prisoner who she was. The astounded S-class hero enlightened him that this particular seer could predict a slew of 100% accurate and more than likely to occur disasters at exactly when and where they would and have most likely been to strike around the world, all in order for the Hero Association to prevent them from coming to pass. After hearing Shicchi's panicked elaboration on how heavily the impact of the most recent prediction she'd made before her death would be come in half a years time, Saitama could not help but simply muse that this disaster that has the Association coordinator so on edge could just as well occur today or tomorrow for that matter. After having been asked who he was by the former, Saitama simply states how glad he is to have come along for the meeting.

Just then as he was finished bemusing over the emergency meeting, the entire building complex shook with thunderous turbulence as though it had been hit by a massive tremor, while outside the complex numerous Tengu like creatures led by the Sky King could be seen gathering around for an all out assault on the surface world. However, the would be incursion was soon dispatch by a UFO like albatross the size of a major metropolitan area. Having already picked up on what had happened to the obliterated A-City outside the Hero's Association HQ Saitama quickly leaped into action even before Genos could erect a response out of him, having already jumped all the way to the rooftop through every single floor of the super reinforced building to get a better view of the enemy at hand.

Initiating his final measure the dreaded Boros struck out at his worthy opponent with his planet killing trump card intending to decimate Saitama and the earths surface layer in one gigantic blast. However,  Saitama, unfazed by this apocalyptic announcement, simply said he would counter with his own winning trump card; his serious series, which not only deflected the genocide wave, which obliterated Boros on the spot, but also parted the cloud cover for several thousand miles across the globe. While he lay dying, admitting he found the excitement he long sought after while making his way across the cosmos, Boros commented that he and Saitama fought to the bitter end with neither giving an inch with the former nodding in compliance. Even though Boros knew full well that Saitama was still holding back the entire time they fought disparaging at how powerful his better truly was with his last breaths, leaving Saitama to solemnly walk away from his fallen enemy in the collapsing fortress.

After finally making his way out of the ruined flagship Saitama met with many other S-Class heroes such as Superalloy Darkshine, Tatsumaki and Atomic Samurai. After being asked how and why he was on the enemy ship, Genos came rushing to the scene concerned for his well being. After a brief conversation over who Saitama was fighting against and how prophesies could have come to pass without his help, which Saitama writes off as bupkis due to prophecies being untrustworthy, Tasumaki bursts into a fit of anger interrupting them both acting as a spoiled brat as she denounces Saitama for what she perceives as interference in her battle and calling him mean names. With some coaxing from Saitama, Genos steps up and tells Tatsumaki to shut up or burn up... seconds before being telekinetically thrown into some debris by her in outrage of being called a shitty brat only to be stopped seconds away from attacking Saitama by Bang who admonishes her for her callous behavior as an S-Class hero.

Pork Cutlet Bowl
As Saitama is out on a walk he's pulled over by two police men looking over for any suspicious activity while on patrol, the curious hero asks why he's being inspected only to find his questions rebuffed due to said local law enforcement's "need to know" basis answer as they take him in for questioning. Through further investigation into his background the two lawmen come to the conclusion that Saitama may be the culprit behind a string of grisly gumshoe assaults that have been occurring around their precinct. Judging from his being jobless, living in a rural abandoned area with blood on his hands makes him only more so apprehensive looking up close. While admitting that an unpopular hero is no different than a part-timer Saitama wonders what the police force's bone to pick with the Hero Association was before enjoying some katsudon offered by the inspector. But as they were still conversing the real culprit behind the string of officer affrontry; a demon level monster threat named Raid Plum began attacking their establishment after shedding his delivery man disguise stating his hatred and assault on the Law was out of revenge for busting him earlier in his life, with the disaster at hand Chief Kuma had to be dragged away from the questioning room to observe the threat. Left without options the head officer made a call of desperation to the same association who he detested knowing full well what it would mean to the dignity of the police, but when the derogatory second chief of operations for the Hero Association; McCoy desired his apposing heckler to cast aside his and the face of the police, Saitama quickly snatched away Kuma's cellphone crushing it before he could voice his dejecting humility clarifying that neither heroes nor cops do their job because people say "I beg you" and that the man on the other end of Kuma's phone wasn't any kind of hero.

Looking to pay the good police chief back for the free food, Saitama offered to handle things on behalf of the men and women of the force and single-handedly took out the monster as the rest of them looked on, goading the creature into attack as he stated he was neither with the police nor a simple civilian. Outside the police station, where countless bystanders, the local news and a horde of heroes from Z City Hero Association HQ sent by the duplicitous operator McCoy who leaked the information to the media and sent out every available upper rank hero in order to further disgrace the organized gendarme garnering public support for the heroes than the long arm of the law. McCoy's plan backfires when a lone police officer steps out of the building carrying out the downed creature on his back much to everyone's shock and awe as well as McCoy's chagrin. All the news channel sponsors present at the scene bustle their way into a police blockade, desperate to know who the mystery officer was that took out the monster attacking them at their office. Before anybody could thank him Saitama had already left the scene, content with having helped the police save face. When asked by another dependent about him Kuma simply stated initially he was thought to be an unemployed man with no valid address but later rescinded his opening statement, simply calling him a hero.

King Arc
Saitama is informed about King's presence thanks to Genos, who gave a short description about him. Genos wonders why King was there. While they talked, a sudden commotion occurred, where the source is the robot G4, whose primary goal is to eliminate King in the order of the "organization". Though Saitama offered on helping, Genos declined in the hopes of making it to the top 10, making Saitama to leave the matter to the cyborg. While King struggled to choose a name in a video game, Saitama entered King's residence. At first, King didn't notice and told Saitama he'd die of shame when his hero name is used to refer to as "Onii-chan". Once King notices Saitama, Saitama states that the window was open, despite it being in the 22nd floor. Eventually, King remembered Saitama from the S-class meeting and quickly changes the video game to an action game, claiming he got the wrong game by mistake. As Genos fought G4, King played video games, which earned the praise from Saitama himself. However, Saitama suddenly addressed King's escape from a fight against the robot. Such questioning was garnered for Saitama wanted to relate to King's strength. As Saitama was going to exit, a bird-like monster appeared, flying directly towards King's room. Lucky for King, Saitama stopped the monster by holding its beak. Saitama gave King a chance to fight the monster. Saitama then wondered if King attracted monsters, making king to reminisce his past. It is then shown that King really was attracting monsters before, only to be stopped by a mysterious figure from time to time. Because of his appearance in the scene, people began to treat him as the hero, giving him the hero name KING. As King was driven to the point where he teared up, silence entered the room, making him think the monster ate Saitama instead. However, Saitama began to notice that all rumors about King were mere lies, though that didn't make him angry. King concluded that Saitama beat the monster and he also learned that it was Saitama who saved King countless of times, albeit Saitama was still young at the time. King began to apologize to Saitama and confessed that he stole the glory from Saitama's accomplishments. Still, Saitama urged King not to quit and just be strong. Saitama went away, holding no grudges against King, and he still wanted to play games with King.

Lobster
After being called over to Bang's dojo, Saitama learns that Bang got a whole bunch of lobsters from his brother and needs someone to help him eat them. Genos complains about them being called out for something insignificant, and tells Bang to call someone else if he needs help eating leftovers, at which point Saitama tells him to stop, saying that they're only helping a lonely old man with his food problem. After Charanko arrives with the vegetables, they start preparing the hotpot while talking about a recent dojo hunter that has been attacking other dojo's. Saitama notices that there isn't any cabbage, interrupting the conversation about the dojo hunter, which annoys Charanko. After seeing Saitama look bummed about the fact that there isn't any cabbage, Genos angrily asks Charanko why he planned to make hotpot without cabbage. Saitama tries to say that it's fine, but Genos keeps arguing with Charanko because he does not feel like he even feels sorry for not having bought cabbage. After Charanko challenges Genos to a match, Bang tries to calm down the situation by saying that he will go buy the cabbage, and asks Charanko to get along with the other two.

After preparing the hotpot (except the cabbage), they hear a loud voice calling a challenge. Looking towards the door, they see a large amount of martial artists coming in, claiming to be from the "Harsh Path Style" and asking for Bang, master of the "Flowing Water, Rock Smashing Fist", so that they may crush the dojo. After Charanko chastises them, saying that this dojo does not tolerate dojo hunting, the martial artists challenge him instead, and start attacking him. Charanko tries to call for help, but Saitama and Genos are still cooking the hotpot and don't notice. After Charanko is kicked back and almost lands on the hotpot, Saitama grabs his gi using his chopsticks, holding him up. One of the martial artists sees the lobster, and moves to crush it saying that it is a luxury not fitting of a martial artist, at which point Genos launches across the room, saving it. When the group tries to attack, Genos knocks one of them threw the wall with a single push, leaving a hole in the wall. Saitama praises Genos, saying that while it might not be their job to subdue dojo hunters, these ones had crossed the line, at which point they try to attack him. Saitama quickly grabs and throws all of them using his chopsticks, leaving several more holes in the wall.

After Bang arrives, he seems rather upset about the condition of the dojo, and asks the last remaining member of the group if they had done it. When the guy tries to say it was Saitama and Genos, Bang angrily says that they are the ones picking a fight here. After the group leaves, Saitama is seen enthusiastically enjoying the hotpot.

The Blizzard Group Arc
Blizzard, along with Eyelashes and Mountain Ape, goes to Saitama's place to convince him into joining their group. However, the latter's casual refusal urged them to take him down, but backfired as Saitama easily knocked out Eyelashes and Mountain Ape. She expresses her will to secure her position as the # 1 in B-Class and attacked Saitama with a psychic barrage, but Saitama is not surprised by her ability. Saitama withstood all of her attacks and even patronizes her about being a hero. She asserts her will and continued to attack, this time with a box cutter, but was caught up by the impact of Genos's attack on Sonic, who evaded it. Saitama quickly got between Blizzard and Geno's attack, which would have probably killed her.

Wondering about Genos's presence, she is more surprised that the S-Class Hero actually called himself the disciple of the B-Class Saitama. Genos recognizes her, but misinterprets her position as being due to a failed attempt at taking down Saitama, when in actuality she was caught in his attack. Sonic then proceeds to attack Genos with exploding shurikens, but they did no damage. The two are on equal footing and eventually Saitama tries to stop them.

Upon observing Saitama's ability while battling Sonic, she found that Saitama is too strong, which is far from the norm for his class ranking. It is revealed that she has an inferiority complex due to her sister's own power. Due to this, she founded the Blizzard group in order to surpass her sister, who is a lone wolf. Still, she reveals that she does not want to advance to A-class due to the A-class heroes being overwhelmingly powerful, such as the disciples of Atomic Samurai and Handsomely Masked Sweet Mask. However, she acknowledges that she can get to upper ranks of A-Class.

In a final attempt to persuade Saitama in joining her faction, Fubuki belittled Saitama, saying he won't advance alone and that there are several other heroes out there that are stronger than he is. However, when King appears demanding Saitama return the video game he borrowed, Fubuki decides to follow him and be a part of his group, noting that the strong are attracted to Saitama, who does not discriminate on strength. Saitama is shortly after given the hero moniker "Caped Baldy" by the members of the Association.

Hero Hunt Arc
Saitama was seen playing video game with King, along with Blizzard and Genos, while being visited by Charanko, who wants know why his master, Bang, expelled him all the sudden. Genos tells Charanko that Bang expelled him because Garou was actively hunting heroes. Saitama does not remember who Charanko is and has to be reminded by Genos that Charanko is Bang's one and only disciple. On the next day, Charanko ignores his master's secret order not to approach Garou and decides to fight Garou, at the same time that Licenseless Rider and the Tanktop brothers also decided to fight, but all are beaten by the rogue disciple.

Saitama visits the heroes, particularly Licenseless Rider, Tanktop Master and Charanko, to give them some bananas as treats and to know more about Garou. He first visits Licenseless Rider and Tanktop Master, where he wants to know about who exactly Garou is, instead of just being Bang's former disciple. Now knowing that Garou is a strong villain, he wishes to meet and battle him someday in person. Saitama later visits Charanko to learn more about martial arts and who he could fight to learn more about it. He is soon offered by Charanko to observe marial arts at the tournament that he was originally supposed to participate in but couldn't due to his injuries. Saitama accepts the offer, however, Charanko advises him not to do something like disguise himself to cover his identity in the tournament. Enticed by the 3 million prize for 1st place, Saitama intends to do exactly that.

After Saitama finds a wig shop, he is attacked by Garou. Garou, thinking that Saitama is after him, tries to attack him with a swift karate chop to the shoulder. However, Saitama is not only unaffected, but also fails to recognize his attacker. Annoyed at Garou for attacking him, Saitama counters Garou's attack by using a karate chop of his own which knocks out Garou almost instantly and then carries on buying a wig for his disguise. On the following day, Saitama prepares himself for the tournament by preparing the wig. Genos sees what Saitama is doing and, believing that Saitama is trying to make up for his lack of hair, decides to help his master by calling Dr. Stench and asking him to transplant the hair fibers that he has onto Saitama. After getting the doctor to agree, he asks Saitama if he is free that day, at which point Saitama is finally able to explain that it is a disguise for the tournament, used to make himself look like Charanko. He then asks Genos to join him in paying them a visit, and to learn what martial arts is really about.

Sense
Saitama is looking for a monster in the K-City Nature Park when he bumps into a fisherman. Saitama and the fisherman have a short conversation about the fisherman's philosophy, allowing an opponent to grow and have another matchup. The fisherman then manages to catch the "King of the Lake", but it is eaten by Lord Great White, the last survivor of the Seafolk invasion. Afterwards, Saitama quickly takes care of Lord Great White and parts ways with the fisherman. On his way, Saitama thinks about the fisherman's statements and tries applying it to his hero career, remarking that unlike the fisherman, he does not have a good competitor. Suddenly, Speed-o'-Sound Sonic appears before Saitama and challenges Saiitama into a fight. He uses his new weapons against Saitama, but it useless and Sonic must leave the match defeated once again.

Numbers
As part of her ongoing efforts to recruit Saitama into her group, Fubuki challenges Saitama and his group to another match with the losers having to do whatever the winner says. The next day Saitama alongside "his group" consisting of Genos, Bang and King all arrive at the Blizzard groups hideout and Saitama signs their contract without even reading it.

Quickly caught in a video game contest, Saitama, Genos and Bang all lose in rapid succession to the Blizzard group. However when it's King's turn he dominates the games and quickly beats all thirty present Blizzard group members. Later the group encounters Child Emperor with his new invention Okame-Chan and Jumping Spider who was rampaging in the area.

King and Saitama both get ratings of "unknown" from the device, according to Child emperor the device has a certain limit if person is too strong or weak. When Fubuki gets rated by the device however it registers her as 20 when the average C-Class is 100. After Fubuki falls into a depression Saitama snaps her out of it by telling her to stop caring so much about what others think of her.

With Fubuki snapped out of her depression she easily destroys the Parasites produced by Jumping Spider after he died. With the battle over Saitama reminds her that she owes him a favor, ultimately treating Saitama's group to a dinner at Restaurant Mammoth.

Monster Raid Arc
Saitama is in Charanko's waiting room looking over a list of the contestants of the tournament. He is then greeted by Sour Face, and Sour Face discusses a tournament incident that happened in the past and his reasons for joining the tournament. Lastly, he talks about the day when Garou rampaged through the dojo. Saitama implicitly states that what Sour Face is doing is pitiful and claims that he will be the one to put Garou down in the end, unaware that he had already beaten Garou before the tournament, which aggravates Sour Face.

After the tournament introductions, Saitama converses with Sour Face when Zakos appears and starts questioning Saitama. Sour Face ends up answering some of Zakos questions. Zakos then reveals that Bang was supposed to be one of the judges and starts mocking the martial arts master. Sour Face starts to feel very insulted, but felt even angrier when "Charanko" did not seem angry at Zakos's comments. Saitama replies that he was not invested in the conversation and is only looking forward to fighting Zakos, but notes that Zakos doesn't seem strong.

The following section contains Webcomic spoilers. You have been warned manga-only readers.

Psychic Sisters Arc
The next day, after encountering Saitama, Black Sperm and Overgrown Rover follow him home as pets. The two formerly dangerous monsters are currently entrusted to Butterfly DX and Chain'n'toad due to Forte losing a bet with Saitama.

Abilities & Powers
Saitama is the titular OnePunch-Man and the strongest character in the series. No enemy has been able to injure him in any way, or even survive from a single earnest punch. A few enemies have survived punches from him, such as any human he has struck, and Boros, whom Saitama empathized with and held back against so as to give him a satisfying fight. Saitama's power is that his body is far beyond human limits, allowing him to achieve astounding physical feats. His strength is so great that it vastly eclipses even artificial beings designed or bred specifically for superhuman combat, such as mechanical beings or the mutated warriors from the House of Evolution. Since no enemies have posed any real challenge to Saitama yet, the upper bound of his strength is likely even higher than it appears. While his power is only limited to heightened human traits - Saitama cannot fly or fire energy blasts - his superhuman abilities more than makes up for the lack of variety in his powers.

The origin of Saitama's immense strength is mysterious and unclear. Although he tells everyone he got his incredible power through mere strength training, no one believes him at all. According to Saitama, after a year and half of 100 daily push-ups, sit-ups, and squats, plus 10 km daily running, he had achieved some level of superhuman strength. This training was apparently so intense for Saitama that he at times felt he might die, and claims that it is what caused all of his hair to suddenly and eventually fall out. He apparently continued his training for another year and half before beginning his hero career. Genos believes that Saitama doesn't actually know or understand how he gained his power, and hopes to learn the secret by sparring with and observing him. It should be noted, that Saitama would complete all parts of the training one after the other without breaks and was battling mysterious beings that appeared during that time, which would have made completing the training more intense than would normally be expected.

Physical Abilities
Immeasurable Strength: Saitama possesses seemingly limitless physical strength and is capable of effortlessly defeating powerful monsters and villains, with a single, nonchalant punch (although this strength is not limited to punches). Saitama's punch is so powerful that many enemies simply explode when struck. He is also shown to effortlessly destroy walls and buildings. An example of this casual, yet overwhelming offensive power occurs when Saitama launches himself from the top of a building, and blasts right through a city-sized meteor. When launched from the earth to the moon by a strike from Boros, he used his jumping power to return to the earth in mere moments, causing a huge shock wave and immense tremors. A "normal" punch from him is shown to be very fatal to someone as durable as Boros. A single "serious" punch is able to somehow counter Boros's destructive energy beam attack, and split the sky in half along the whole planet. Saitama has shown to be able to control the strength of his attacks, but still tends to go overboard, occasionally causing mass devastation in the aftermath.
 * Enhanced Leap: His inability to fly is somewhat compensated by his ability to use his strength to leap tremendous heights and distances. This can be shown when smashed his head through the ceiling of a gymnasium during the hero tryouts. He was also able to smash a building into its foundation just by leaping off from its roof. His greatest feat in this regard, however, was when he leap from the surface of the moon and ended up back on Earth at a specified point.

Immeasurable Speed & Reflexes: Saitama was able to complete a 1500 meter dash in an instant during his hero tryouts. He has proven able to effortlessly keep up with Sonic, who is able to move at above hypersonic speeds. Even Genos' computerized targeting systems have difficulty tracking him. Saitama has also shown the ability to run-down a building to save a piece of salmon he was having for lunch and leap back up said building without on-lookers noticing he had even done so. His speed is so impressive he can outpace even the likes of Lightspeed Flash easily dodging his sword swings. Ironically, despite his incredible reflexes and speed, he still has problems squashing a simple mosquito.
 * Afterimages: He is so fast that he leaves afterimages when moving at high speeds, and is agile enough to dodge Beast King's rapid-fire Limb cutter attacks while moving in for the kill. After assaulting Saitama with a flurry of punches in his practice fight, Genos realized that he was fighting his afterimages.

Extraordinary Senses: Saitama's senses are far beyond the human norm, being able to keep track of extremely fast opponents, such as Sonic easily. He also seems to have developed a sixth sense; being able to dodge danger even though he hasn't seen it. Nevertheless, Saitama's senses do not have the same degree of 'resolution' as some of Genos' sensors, which can detect and distinguish foes at a greater distance. In spite of it however he does possess impressively sharp hearing, being able to pick up on various chatter from bystanders a good distance away even while fighting monsters and the like. He is also able to see in the dark as he was able to spot a kid a great distance away during the night.



Invulnerability: Saitama can withstand blows from extremely powerful beings such as Carnage Kabuto without taking a scratch or feeling any pain. When Genos created a huge, spherical blast of flame to kill Mosquito Girl's mosquitoes, Saitama remains standing right next to him totally unharmed and unperturbed. He also survived being kicked to the moon by Boros in his fully powered state, and going from the Earth to the moon and back with little to no damage from leaving and entering the Earth's atmosphere (only his clothes were burnt). Blunt strikes aside, Saitama was able to casually stand near Genos' incineration blast without taking damage. Saitama also prefers to dodge or block attacks using edged weapons rather than take them head on, as he sometimes does with strikes from fists or blunt objects. It has been shown that, despite the dangers of holding ones breath in space, Saitama is able to do so with no negative effects on his body. However, it is worth noting that Saitama does not see mosquitoes as a potential weakness, preferring to hide from the mosquito swarm heading his way rather than confront it, although he did not know that a monster was responsible for the swarm in the first place.
 * Psychic Resistance: Fubuki has noticed that due to Saitama's astonishing will power he is immune to psychic attacks. However, it is still noteworthy, that his muscles "twitched" when Tatsumaki used her powers on him.

Fighting Styles
Saitama's fighting styles usually consists of basic techniques in fighting, such as punching. However, these basic techniques are increased infinitely in terms of strength and impact on the opponents because of Saitama's strength. Garou noted, that most of Saitama's moves are wasted and that he is actually a total amateur in fighting with no particular skill.

Normal Series: Saitama's Normal Series consists of techniques in which he puts little to no effort into attacking. Even though his attacks are loose in this style, most opponents tend to be finished off easily due to Saitama's extreme strength and speed.
 * Normalpunch.gifConsecutive Normal Punches (連続普通のパンチ, Renzoku Futsuu no Panchi): Saitama launches a volley of quick, single handed punches from his right. These blows have been shown to be powerful enough to blow strong or large body types apart. Depending on the power of the attack, this technique can occur in an instant. It was first used against the Beast King.
 * Two Handed Consecutive Normal Punches (両手・連続普通のパンチ, Ryōte Renzoku Futsū no Panchi): Saitama launches a volley of quick punches from both hands. This attack is much like Consecutive Normal Punches, but the rate at which the punches are being thrown is essentially twice as fast. It was first used against the Garou.

Serious Series (必殺マジシリーズ, Hissatsu Majishirīzu): Saitama's Serious Series consists of techniques in which he puts effort into attacking. While he normally punches without putting in much effort, when Saitama gets serious in a fight, his techniques become tremendously powerful.


 * SeriousPunch.gifSerious Punch (マジ殴り, Maji Naguri): Saitama throws an extremely powerful punch. The full extent of this attack is unknown, as it never directly hit an opponent, however, it was able to completely negate and destroy Boros' Collapsing Star Roaring Cannon, a beam capable of wiping out a planet's surface. The shockwave alone from the punch was powerful enough to part clouds on a global scale and defeat Boros.


 * Serious Side Hops (マジ反復横とび, Maji Hanpukuyokotobi): Saitama hops from side to side rapidly. Doing so allows him to create a multitude of afterimages. He has been shown to be able to walk forward while doing so and the shock wave caused by it was enough to break Sonic's Ten Shadows Burial.
 * Serious Table Flip (マジちゃぶ台返し, Maji Chabudai-Gaeshi): Saitama digs his fingers into the ground and flips a large amount of landmass thousands of meters into the air.
 * Serious Headbutt (マジ頭突き, Maji Zudzuki): Saitama confronts an attack with his head and uses enough force to double the force returned.

Hero Rating
Saitama's rating determined by the Hero Association. Saitama's rating determined by Genos.

Anime and Manga Differences
Episode 1 Episode 2 Episode 3 Episode 4 Episode 5 Episode 6 Episode 7 Episode 8 Episode 9 Episode 10 Episode 11 Episode 12
 * Saitama walks home at night after going to the market and sees a cat, the cats runs off only to be scared off by Super Custom YO649Z Mk. II which sees Saitama and monologues his origins. But is quickly defeated after trying to threaten Saitama while talking about his bald head. Saitama then goes home, washes his clothes, eats his supper and goes to bed.
 * Before and during Super Custom YO649Z Mk. II's monologue, Saitama talks about how he lost his ability to feel emotion due to his training which was before his dream fight while in the manga it was right before he tried to kill the mosquito later on.
 * Saitama's dream fight was much longer in the anime, including the fact he fought subterranean people both his size, and above to the point of being giants.
 * He feels the thrill of battle as we are shown a heartbeat.
 * He hears the news report about the mosquito infestation before trying to swat the mosquito.
 * Saitama went at super speed trying to kill the mosquito that flew to his house.
 * Swatting Mosquito Girl into the side of a building splattering her blood and continues on afterwards. Saitama actually splits the earth and the clouds after swatting her.
 * His fight with Carnage Kabuto is much longer as he is pummeled around the training room. While thinking of what day it was.
 * Saitama is writing up an resume to be a hero for the Heroes Association.
 * Saitama talks about how if he took a wrong step, he might have become part of the Paradise Group since they were that much alike writing up his resume to be a hero.
 * Saitama and Genos walk to the Heroes Association Sign up building in the end of the episode.
 * We see Saitama do more parts of the Physical Exam like One Shot, Whack-A-Mole, and Punching Machine.
 * His sparring match with Genos is much longer.
 * Saitama's fist of death that ended his sparring with Genos annihilated the canyon behind Genos and reformed the clouds.
 * Saitama saves a small boy about to be hit by a vehicle that was in the air during Sonic's assault by blocking it with his arm. While in the manga he used a tree to block the car from hitting the boy.
 * Saitama karate chops Sonic while in the air instead of on the ground.
 * Genos explained to Saitama that there are four types of threat level, but in the manga there are five types of threat level; Wolf being the lowest.
 * Saitama heads home with Genos complaining about how he remember the guy that called him bald, as well as listening to Genos when he says he will follow him even if the world is against him.
 * Saitama and Genos are running to J-City
 * Meets up with License-less Rider
 * He and License-less Rider go off to where the monsters in J-City should be, only to see Sonic speed by them, thinking he was a citizen that took a shower but lost his way to the shelter. He leaves License-less Rider to go search for him.
 * Saitama punches the Sea King with enough force that it stopped raining.
 * In the anime, Saitama and Genos mail is dropped off by a drone, in the manga it is parachuted.
 * We have a flashback of Saitama riding with License-less Rider as they search for the monsters, and he doesn't laugh at License-less Rider when he says he is C-Class. Saying that it is a difficult job to keep up with the weekly quote.
 * Saitama is seen getting his tea from a small robot during the S-Class meeting.
 * Saitama reaches the Control Room instead of the Throne/Power Core Room to face Geyunganshoop.
 * His fight with Boros is much longer.
 * Instead of hearing Saitama's thought, we hear only the vacuum of space as Saitama is picking up a moon rock and plays with it to see the gravity. When he understands how it works he tosses it aside before he makes his jump back to Earth.
 * His Consecutive Normal Punches destroyed Boros' body instead of tearing it apart, while the shockwave of his punches obliterated parts of the ship in the background.
 * Saitama helps Genos out after he was slammed into a piece of rubble by Tatsumaki, only to break off his left arm.
 * Saitama appears jumping to Pluton and destroying him in one punch. Later he once again curses to the heavens about how the fight ended in One Punch the same way when he defeated Vaccine Man.

Quotes

 * (To Vaccine Man) "Just an average guy who serves as an average hero"


 * (To Marugori) "Having an overwhelming power is boring as hell."


 * (To Genos) "If the Heroes run and hide, who will stay and fight?"


 * (To Genos & Carnage Kabuto) "The true power of us human beings is that we can change ourselves on our own."


 * (To an opposing crowd) "Let me make one thing clear! I'm not working as a hero because I want you morons to admire me! I do it 'cause I want to! "


 * (To King) "Is it true? All the rumors about your strength and fight history were a lie?" "Did you seriously piss yourself because of that bird?"


 * (To Fubuki after closing in on her) "You won't survive. You don't get what hero means. There's a lot of incredibly strong bad guys in the world. Those who oppose them are called heroes. Even if they are alone. You, who gathers weaker subordinates to feel strong, won't make it. At this rate, you are gonna cry sooner or later. When a monster stronger than you shows up, none of your subordinates will save you. Factions? Newbie crushing? Keeping your ranks? They have nothing to do with anything! Do not look down on heroes, you moron!"


 * (To Glasses) "Do you honestly think you won't get any stronger for the rest of your life? Instead of sitting around frustrated, it's better to keep on moving forward. I'm going now. Today's a special day in case you didn't know. The market's selling veggies at 30% off."


 * (To Boros) "OK."


 * (To Boros) "You are still conscious? You really are strong."

Trivia

 * Saitama is ranked 1st in the character popularity poll.
 * In the other hand, young Saitama is ranked 10th in the character popularity poll.


 * Arataka Reigen of Mob Psycho 100 has Saitama as a background on his cellphone in chapter 9.5.


 * Young Saitama is also seen wearing a Mob Psycho 1000000 shirt in 200 Yen.


 * Saitama has a Mob Psycho 100 manga on the floor near his futon in Paradise Group.


 * Near the beginning of the Manga the color of Saitama's cape was red (House of Evolution Arc) but later was changed to white (Meteor Arc).


 * Saitama has a cameo appearance in a dream sequence in chapter 80.5 of Mob Psycho 100.


 * Saitama is always late during the times that other (registered) heroes would be defeated, after which he easily defeats the enemy.


 * Despite being the strongest in the series, few know his true strength, such as Carnage Kabuto, Boros, Genos, Bang, Sonic, King, License-less Rider and Fubuki.


 * He finally got most of many fans whom admire his strength and his own pure heroic will during his participation in a costume contest.


 * According to Genos, Saitama's true potential does not lie within his appearance, but in the way he did his best on training himself to become a true superhero caused him to receive his own super strength after three years of training.


 * Due to his unimpressive appearance many enemies and allies tend to think that he is weak at first glance; only Boros and Carnage Kabuto could sense his immeasurable strength at first glance.


 * Saitama is indirectly responsible for the Heroes Association's creation, having saved the grandchild of multi-millionaire Chinner from Crabrante three years prior to the story-line; Chinner would then found the Association to protect humanity from the mysterious beings.


 * Saitama's seiyuu is Makoto Furukawa, known for the voices of Shigou Kakei (Aldnoah.Zero), Yutaro Kindaichi (Haikyuu!) etc.


 * One came up with Saitama's rather simplistic design when thinking about how many "cool looking superheroes there were." As Onepunch-Man was a pun on Anpanman, Saitama's appearance could be said to be based off of Anpanman's. His hero costume is the same as Anpanman's costume with the colors reversed (Anpanman had a red jumpsuit with yellow gloves and boots).


 * Near the end of the opening of the anime, Saitama actually performs a Serious Strike from his "Super Move Serious Series" but a bit differently. He actually places his left hand over his right hand while preparing to use his Serious Strike. This is actually a parody of Gon Freecss from Hunter x Hunter while performing his signature "Rock".


 * Saitama's name is mostly likely derived after the city of Saitama, located in Japan, where ONE currently lives and first started drawing the series.