Saitama

Saitama (サイタマ Saitama) is the main protagonist of OnePunch-Man, and the most powerful hero alive. Having supposedly trained himself to superhuman condition, Saitama faces an existential crisis as he is now too powerful to gain any thrill from his heroic deeds.

Appearance
Saitama is a bald man of thin, but well-built physique and 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 intense hero training. Three years before the storyline, Saitama has black spiky hair. Saitama's eye color is unclear, as his eyes are usually represented by dots.

Saitama is usually deliberately drawn in a simpler style than other characters, with a very rounded head and only a simple mouth and eyes. When drawn in a more 'action-oriented' style with more detail, Saitama is revealed to have sharp features, dangerous looking eyes, and chiseled musculature. 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 cape.

Personality
For a superhero, Saitama is rather laid back. Because even the mightiest foes pose no challenge to him, he doesn't take his hero work very seriously. In spite of this, he is constantly searching for an opponent that can challenge him, since his superhero work is beginning to bore him because it's too easy. The combination of his attitude, unstoppable strength, and distinctively simple and 'unimpresive' appearance often render his battles into anticlimaxes. Saitama will usually allow his opponents to rant about their motives and power up into their strongest forms before suddenly and nonchalantly obliterating them with one punch.

Plot
Saitama first appeared watching a news report on Vaccine Man attacking the city. Seeing the destruction, he remarks, "I should go...". He then appears on the scene, saving a little girl from being killed. After listening to the monster's monologue, he simply kills it with a mere punch. After this, he screams out in frustration at another easy victory; a pattern which will be repeated in future battles.

Saitama later gains a 'disciple' of sorts in Genos, a teenage cyborg who admires Saitama's overwhelming strength. Genos's dramatic and 'cool' abilites and personality make him a foil to Saitama, as he resembles a traditional superhero or anime protagonist far more so than Saitama.

Abilities
Saitama is by far the strongest character introduced so far. No enemy has so far been able to injure him in any way, or to survive even one of his punches. 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 especially for superhuman combat, such as the android Genos or the warriors of the House of Evolution. Notably, since no enemies have yet posed any challenge to Saitama, the upper bound of his strength is likely even higher than it appears. However, his power is notably limited to heightened human traits; Saitama cannot fly or fire energy blasts, for example.

The origin of Saitama's unbelieveable strength is mysterious and unclear. Although he tells everyone he got his incredible power through mere strength training, no one believes him. According to Saitama, after a year and a half of 100 daily push-ups, sit-ups, and squats, plus ten kilometres daily running, he had achieved some level of superhuman strength. This training was apparently so intense for Saitama that he at times felt as if he might die, and claims it is what caused all of his hair to suddenly and prematurely fall out. He apparently continued 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 to it by sparring with and observing him.

Super Strength: Saitama is capable of effortlessly defeating any enemy, even ones many times his size, with a single, nonchalant punch (although this strength does not extend only to punches). Saitama's punch is so powerful that many enemies simply explode when struck by it. He has also been known to effortlessly destroy walls and buildings with his attacks. An example of this casual, yet overwhelming offensive power occurs when Saitama uses an inelegant smacking motion to smash Mosquito Girl through a nearby building and into the sky, killing her. His dialogue implicitly likens the attack to swatting a mosquito. His inability to fly is somewhat compensated for by his ability to use his strength to leap tremendoes heights and distances.

Super Speed: Saitama was able to complete a 1500 metre dash in an instant during his hero tryouts. He has proven able to effortlessly keep up with Sonic, whose main ability is super speed. Even Genos's computerized targeting systems have difficulty tracking him. He is so fast that he leaves afterimages when moving at speed, and is agile enough to dodge the Beast King's rapid-fire Limbcutter attacks while moving in for the kill.

Extreme 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's sensors, which can detect and distinguish foes at a greater distance.

Invulnerability:  Saitama can withstand blows from extremely powerful beings such as Asura Rhino without taking a scratch or apparently feeling any pain. Indeed Saitama has only been seen to bleed from a blow during a dream in which he imagined facing opponents close to his level. When Genos created a huge, spherical blast of flame to kill Mosquito Girl's mosquitoes with Saitama standing right next to him, Saitama was totally unharmed and unperturbed, although his civilian clothes were incinerated. It is worth noting that mosquitoes seem to be able to penetrate his skin, and that Saitama seems to prefer 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.