One-Punch Man Wiki

The Saitama Introduction Arc is the first arc of the One-Punch Man series and the first arc in the Introduction Saga.


The story begins with the Dragon-level threat monster Vaccine Man destroying a city, while Saitama watches the event take place on TV, deciding to intervene. As Vaccine Man is about to kill an innocent child, Saitama shows up to save the child and tells Vaccine Man that he is a hero for fun. Vaccine Man transforms, and prepares to fight Saitama, but is easily killed in a single punch. Saitama then gets on the ground proclaiming that he was upset by how easy that was.

We then flashback to when Saitama encountered the monster Crablante, who was after a young child that drew nipples on his shell. Saitama killed Crablante to save the child and afterward started training to become a hero. Back to the present, Saitama is shopping in a grocery store. However, he is interrupted by The Brain and Brawn Brothers rampaging. He swiftly defeats them, but accidentally destroys B-City in the process.

While in his apartment, Saitama is attacked by the Subterraneans who give him his first real fight in 3 years, but as he is about to face off against their leader it is revealed to be just a dream. After the real Subterraneans invade the surface, Saitama instantly kills the Subterranean King, and they retreat.

Story Impact[]

  • This protagonist, Saitama, is introduced along with his frustration at being so overwhelmingly powerful that he almost always wins his fights with a single punch.
  • B-City and D-City are destroyed by Marugori and Saitama.
  • In a later arc, it is revealed that credit for defeating Vaccine Man went to King, who happened to be there at the time.
  • It is revealed that the boy that Saitama saved from Crablante was the grandson of a wealthy man named Agoni, who would later found the Hero Association after the incident.

Battles and Events[]

Site Navigation[]

Story Arcs
Introduction Saga Saitama Introduction Arc House of Evolution ArcParadise Group Arc
Hero Association Saga
Human Monster Saga Garou Introduction ArcThe Blizzard Group ArcHero Hunt ArcMonster Raid ArcSuper Fight ArcMonster Association Arc
Neo Heroes Saga
Saitama Introduction Arc
Manga Chapters 1234
Manga Volumes
Webcomic Chapters 1 • 2 • 3 • 4
Fights Saitama vs. Vaccine ManSaitama vs. MarugoriSaitama vs. Super Custom YO649Z Mk. IISaitama vs. Subterranean King