One-Punch Man is a popular Anime series based on Manga of the same name, which is based on a Web-comic of the same name. The protagonist of this show is Saitama, a normal human who is skinny and bald. All that is a normal thing until he picks up his costume and becomes a hero. As his name says, this character can defeat anyone with just a single punch doesn’t matter if it’s a normal human being or an Alien.
He comes from a place where Monsters are everyday things, and they roam around every street. There also happens to be a Hero Association that handles these monsters with the help of Hero’s registered under it. Saitama starts fighting monsters independently until he runs into Genos and realizes that he can do this job for a living at the Hero Association. As the plot goes forward, we learn that this world is infested with powerful monsters.
So let’s dive in and find out why Saitama is so strong?
The World of One-Punch Man
You may or may not have noticed it but the world of One-Punch Man is very different from a normal world. It has monsters roaming around every corner of the streets. The monsters themselves share a story that is sometimes unique and amusing in a sense. For example, the first monster Saitama encountered, Crablante, turned like that after he ate lots and lots of Crabs. A monster turned into a car type one because he customized himself.
So the main point coming out of this is that if you do something repeatedly, whether being less or more passionate, you get turned into that thing.
What is Saitama?
One of the very basic theories regarding the beginnings of Saitama is that he is certainly not a normal Human by any means. His training has led to a scenario where we see Saitama easily defeating any monster with just a Punch. The fact that why haven’t the Hero association’s principal enemies, the Monster Association (MA), taken any stance on finding out the guy who is taking down every monster in the Ghost town Z-city? He usually finishes the monsters he encounters leading to rumors only. No one knew the true potential of this plain-looking Hero.
Why is Saitama so Strong then?
Well, the main answer is already given by the protagonist himself. As he stated that humans are so special because we can change ourselves. It’s only humans who can fully dedicate themselves to anything if they want to. In one of the Manga chapters, we know the main reason behind this from Dr. Genus, the guy from House Of Evolution. He said that Saitama’s strength was far greater than any human evolution through cybernetics or Practical Evolution.
Saitama removed his Limiter.

A still from One-Punch Man season 1 Episode 3
What is Limiter?
Dr. Genus explains that every being has a limit to how much it can grow. Too much Power brings burdens to the wielder that creates issues, they could become a rampaging and mindless monster, this is why God created every living being with a range of growth that ensures their sanity and survival. This growth restriction is called Limiter. However, Saitama pushed himself so far he surpassed his limitations and removed his Limiter.
Further, he added that Humans become Monsters because of the desire to become something else through their bad habits, a complexity, or a burst of dissatisfied frustration. They begin their transformation due to their environment that causes an anomaly in their cells. At the same time, others are made through the Power of chemicals like with his research. Numerous cases of no-human life-forms becoming monsters due to pollution and the like have also been found. They, however, become completely different beings that have nothing to do with removing his Limiter.
Examples of this would be the seafolk or the alien monsters in a broader sense, but they were such sentient beings to begin with. In the case of heroes, they were born with enough potential, Genius intellect, and Esper Powers. But Saitama is different. He is an accustomed person who opened the way of limits and broke his LIMITER. He is not the only one that has broken the basic limits of human power-limit, but Saitama is seen to be far stronger than any other being seen in the series to date. There is a lot more to explain the origin of Saitama’s powers.
