10 Best Episodes of ‘One Punch Man’

There is a reason people still talk about ‘One Punch Man’ long after its debut. The series builds a world of cities labeled by letters, a formal Hero Association, and a revolving door of monsters that seem unstoppable until a certain caped baldy strolls in. Episodes mix sprawling battles with small character beats, and the result is a string of stories that are easy to revisit and remember.

This list gathers ten standout chapters from across the show that map Saitama’s path from anonymous citizen of City Z to a name known throughout the Association. You will find early showdowns, big turning points, and the invasion that pushes every S-Class hero to act. Each entry includes concrete details to help you jump back to the right episode or catch up on the arcs that tie the series together.

‘The Strongest Man’

Saitama’s routine in City Z takes shape here, from grocery runs to monster interruptions that end in a single punch. The episode opens with Crablante and later introduces Vaccine Man, setting the tone for how threats appear without warning and how quickly Saitama resolves them when he finally steps in.

A dream sequence shows Saitama imagining a hard fight against subterraneans before he wakes to an ordinary day, which highlights the gap between his power and the challenges around him. By the end, you know where he lives, what he looks like under the cape, and why the Hero Association has not identified him yet.

‘The Lone Cyborg’

Genos enters the story while chasing Mosquito Girl, and his clash with her reveals the scale difference between an S-Class level cyborg and the series lead. After Saitama ends the battle, Genos asks to study under him, which starts the mentor and disciple thread that runs through the season.

The episode also seeds Genos’s past with the House of Evolution and his connection to Dr. Kuseno. These details set up later investigations, upgrades, and the loyalty that keeps Genos close to Saitama even when missions scatter heroes across multiple cities.

‘The Obsessive Scientist’

The House of Evolution abducts Saitama for research, which pulls him and Genos into Dr. Genus’s underground facility. The lab’s clone workforce and the record of accelerated evolution explain how the organization produces enemies at a speed that alarms the Association.

Carnage Kabuto’s release turns the base into an arena, and his Asura Mode demonstrates a monster ceiling that still falls short in front of Saitama. The fight ends fast, and the aftermath shows Dr. Genus abandoning his experiment after seeing how far outside his model Saitama really is.

‘The Modern Ninja’

The Paradisers march on a construction magnate while wearing impact suits, which introduces a civilian faction with destructive tech rather than monster biology. Saitama gets pulled in after he loses the one thing he wants to protect that day, his favorite outfit, which places him on a collision course with a new rival.

Speed-o’-Sound Sonic arrives as a freelance bodyguard and meets Saitama during the pursuit. Their first encounter sets up a personal feud that pops up throughout the series, and it also shows how hired talent, criminal crews, and lone operators complicate the Association’s ability to keep order.

‘The Ultimate Master’

The Hero Association entrance exam splits into physical and written tests, and Saitama’s perfect physical results contrast with his weak written score. The placement that follows assigns him to Class C, while Genos lands in Class S, which explains their very different mission alerts and expectations.

Registration makes Saitama an official hero, gives him a public ranking, and requires him to complete quotas to avoid expulsion. This structure drives the next few episodes as he clears petty incidents between larger threats, and it explains how citizens track and judge heroes in real time.

‘Unparalleled Peril’

An emergency summons brings S-Class heroes to Association headquarters after the seer Shibabawa predicts a planet level disaster. Her warning and sudden death put everyone on edge, which leads the Association to raise alert levels across the cities and prepare for a coordinated response.

The crisis arrives with a massive ship appearing over a metropolitan center and firing without warning. The episode lays out how communications, evacuation routes, and hero deployments work under pressure, and it shows which S-Class heroes respond first when the attack begins.

‘The Deep Sea King’

Heavy rain signals the arrival of the Seafolk, and the Deep Sea King begins clearing out defenders in J-City and its shelters. A-Class and below step in to slow him down, and their attempts show how acid spit, regeneration, and weather shifts stack the fight in the enemy’s favor.

Genos engages the king near a shelter to protect civilians who cannot evacuate, and the damage to his chassis shows the cost of holding the line. The episode ends with the city still under threat, which sets up the confrontation that follows inside the shelter itself.

‘Unyielding Justice’

Mumen Rider confronts the Deep Sea King at the shelter after seeing injured heroes and frightened families. His stand buys minutes that matter for evacuations and medical care even though the outcome is never in doubt, and the crowd inside the shelter becomes a witness to how different heroes approach the same job.

Saitama arrives and ends the crisis in one punch, then redirects credit toward the heroes who fought before him to steady public opinion. The fallout shows how citizens debate accountability after disasters, how the Association communicates results, and how hero reputations can rise or fall based on a few details.

‘The Dominator of the Universe’

While S-Class heroes battle outside against Melzargard’s regenerating forms, Saitama infiltrates the alien ship through a hole he makes in the hull. Inside, he eliminates Groribas and Geryuganshoop with ease, which demonstrates the gap between the invaders’ elite guard and the show’s main character.

The path through the vessel maps its layout and command structure, from corridors filled with lesser troops to the throne room where Boros waits. By the last moments, both forces have revealed their trump cards, and the stage is set for a duel that pushes the setting to its limits.

‘The Strongest Hero’

Saitama and Boros fight across the alien flagship, through bulkheads, and briefly into the upper atmosphere before returning to the ship. Boros’s ultimate beam and Saitama’s Serious Punch collide, and the result ends the invasion and leaves the city facing reconstruction on a scale that the Association has not handled before.

The closing scenes explain how the ship’s destruction affects urban districts and how the Association plans to rebuild and reorganize after the attack. Surviving heroes take stock of injuries and resources, and new rumors begin to spread about what might be waiting beyond the next emergency call.

Share your own favorite episodes of ‘One Punch Man’ in the comments so everyone can compare notes and fill in any must-watch moments we missed.