Saitama (サイタマ, Saitama) is the main protagonist of One-Punch 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 is currently registered with the Hero Association as a B-Class Rank 7 professional hero 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; Viz: Bald Cape).
Saitama is an indifferent person. Even the mightiest foes pose no challenge to him, so he doesn't take his hero work seriously and defeats monsters with no effort. Since his hero work has begun to bore him, he is constantly searching for an opponent that can provide him with a challenge. The lack of any such opponents has led him to suffer from a self-imposed existential crisis, and he claims that his ability to feel any and all emotions has dulled considerably[4]. He stated that he just became a hero because it was his dream and for self-satisfaction and that before becoming one, he used to suffer from anxiety issues. Despite his boredom, Saitama does not ignore crime.
The combination of his attitude, unstoppable strength, and 'unimpressive' appearance often causes his battles to become anticlimactic. Saitama will usually allow his opponents to rant about their motives and power up into their strongest forms, before obliterating them with a single punch. However, if they begin to ramble on too much, then he will either interrupt them or just punch them.
A running gag about Saitama is his inability to remember people's faces and names, as seen when he forgot Speed-o'-Sound Sonic's[5] name and could not remember who Tanktop Tiger was[6]. Because of this, he always ends up pronouncing people's names incorrectly.
Saitama has been shown to be very humble, as he purposefully let the masses turn against him in order for the defeated heroes to be given credit for their efforts, even claiming that they had weakened the Deep Sea King before his arrival.[7] He did the same for the police station, killing a monster while disguised as a police officer, despite potentially gaining much fame had he revealed who he actually was.[8] He also didn't mind that King took credit for all of his achievements.[9]
Another surprising thing about Saitama is that he is very 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[10] 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.[11]
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, with whom Saitama sympathized, due to suffering from similar circumstances. Though in the end, Boros still couldn't draw out Saitama's full power.[12]
Saitama does not actually care if people insult him, and he usually ignores them and says that they need a hobby[13]; the only insult that could get a reaction out of him is when anyone mentions his baldness[14][15]. He has shown dislike towards his officially assigned hero name, Caped Baldy. Thus, even after receiving it, he always refers to himself as Saitama. He also shows a measure of concern when it comes to bargains and deals, as seen when he fought Carnage Kabuto, where 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 beating him around[16]. Despite his general indifference to most things, Saitama was genuinely shocked when he realized that no one actually knew of him, despite his achievements, curious as to why he doesn't have any fans. This reaction shows that while he isn't necessarily into hero work for the fame, he certainly doesn't object to it[17]. Another running joke is Saitama's jealousy of higher rankings, such as when he grew irritated when Genos listed off all of the comments made by fans about how amazing Genos is in their eyes.
Saitama demonstrates impressive restraint with his power, considering that he is easily capable of splitting the sky, or jumping from the moon to earth. 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 only ever uses enough strength to knock them out.
Link Below:
http://onepunchman.wikia.com/wiki/Saitama