One-Punch Man Wiki

"The Deep Sea King" is the eighth episode of the One-Punch Man anime series.


A Seafolk messenger announces that the Seafolk are coming to the surface to kill all the humans. Saitama is on his way home from shopping and stops by to punch the messenger. Mumen Rider is late to the scene and sees only the destroyed body of the creature, and hears the crowd talking about Saitama. Mumen Rider looks Saitama up on the internet and sees that he is powerful, but opinions are divided on him.

Deep Sea King defeats Stinger

At the coast, several large Seafolk monsters emerge from the sea, threatening J-City. The A-Class hero Stinger challenges them with his powerful Bamboo Shoot weapon. Meanwhile, Genos is drying dishes with his built-in equipment as Saitama watches a news report about Stinger's battle against the Seafolk. The two decide to head out to confront the threat. Back at the fight, Stinger takes out the last four Sea-Folk with a Gigantic Drill Stinger Quadruple Thrust attack, but is then bested by the Sea King, the leader of the Seafolk. Saitama, Genos, and Mumen Rider all set off to confront the threat. Genos splits off from Saitama to scout ahead. Various other powerful humans confront Sea King to no avail, including Lightning Max, Puri-Puri Prisoner, and Speed-o'-Sound Sonic. Sonic fights the Sea King to a standstill, until the Sea King is moistened by the rain, thus unleashing his true form. Sonic is forced to retreat.

Saitama gets serious

Meanwhile, Saitama and Mumen Rider meet each other on the way to the fight. Saitama goes off to find Sonic who he sees running naked through the rain. Mumen Rider gets a phone call from Hero Association headquarters about the location of the Sea King and decides to go confront the monster, who has just broken into an emergency shelter and has taken down the heroes inside, including Sneck, and is dispatching the heroes there. Saitama returns to where he met Mumen Rider to find a discarded cell phone.

Characters in Order of Appearance[]

Manga and Anime Differences[]

  • Mumen Rider riding to the first Seafolk was not in the manga.
  • The Seafolk did not talk to Saitama in the manga. He simply punched him without warning.
  • Mumen Rider researching Saitama online was not in the manga.
  • In the anime, Genos did not mention how the C-Class Rank 1 hero has not risen into B-Class in over half a year and the B-Class Rank 1 was even worse.
  • Mumen Rider was not shown watching Stinger fighting the Seafolk on TV in the manga.
  • Genos and Saitama did not pass the C-Class heroes riding in a car in the anime.
  • Mumen Rider meeting the C-Class heroes in a car is anime original.
  • In the anime, Lightning Max did not also look at Stinger through his telescope. He is also sitting on a water tank instead of lying on the roof like in the manga.
  • In the anime, after Puri-Puri Prisoner tells Sonic the reason why he is in prison, Sonic does not tell Puri-Puri Prisoner that he needs to be locked up.
  • Puri-Puri Prisoner does not knock the Deep Sea King nearly as high in the anime as he did in the manga. Sea King also did not do a back flip in the manga.
  • Sonic does not comment on how Puri-Puri Prisoner lost his balance from Deep Sea King's punch in the anime.
  • Saitama and Mumen Rider meeting is anime original.
  • All Back-Man thinking to himself before fighting the Deep Sea King isn't shown.
  • Sneck and the others fight against the Deep Sea King wasn't shown in the anime, only their defeat.


  • Stinger and Lightning Max both give the episode monologue at the end of the credits.


Season 1 Episodes 123456789101112
Season 2 Episodes 123456789101112
Sea Monster Arc
Manga Chapters 23242526272829
Manga Volumes
Webcomic Chapters 24 • 25 • 26 • 27 • 28 • 29 • 30 • 31
Fights Stinger vs. SeafolkLightning Max vs. Deep Sea KingPuri-Puri Prisoner vs. Deep Sea KingSpeed-o'-Sound Sonic vs. Deep Sea KingSneck, All Back-Man, Jet Nice Guy and Bunbun Man vs. Deep Sea KingGenos vs. Deep Sea KingMumen Rider vs. Deep Sea KingSaitama vs. Deep Sea King