Supreme Hero Arc

The Supreme Hero Arc is the nineteenth arc of the One-Punch Man series.

Plot
Saitama encounters Rangor, one of the nine warriors of the Dragon Alliance, and defeats him with a single punch. He then comes across a group of people calling themselves the Saints. They explain how by defeating Rangor, Saitama has protected the Cruel Dragon seal and saved the world, and then tell the legend of Cruel Dragon: a creature that descended upon Earth, taking countless lives and scorching the land. They explain that ancient warriors managed to weaken the dragon with costly sacrifices, allowing seal masters to seal away the essence of the dragon in nine seal stones, which are now scattered in temples across the land. This brought rise to two groups: the protectors of the seal stones, the Saints, and a group hoping to resurrect the dragon, Deathbone. The two groups have been in conflict for 800 years, but Deathbone recently increased their activity, taking advantage of the recent frequent monster incidents. One of the Saints hold down a member of Deathbone, who begins to monologue as he loses consciousness, until Saitama throws a bucket of water on his face. Saitama eventually resolves that if the dragon will resurrect at some point, it would be smart to resurrect it promptly to defeat it quicker. Much to the Saints' dismay, Saitama picks up the Deathbone member and flees from the Saint members chasing after him, who help him locate all nine seals. After the Deathbone member conducts the ceremony, the Cruel Dragon resurrects, and Saitama defeats it with a single punch.

Saitama picks out groceries.

Later that night, Saitama meets up with Genos on a street leading towards Former A-City. Genos is visibly damaged and explains that it is from a battle against a powerful demon level monster when Saitama asks, and requests another spar with Saitama. He then mentions that Dr. Kuseno has shown great interest in Saitama's physical abilities and wishes to collect his data. Saitama asks Genos what he bought and Genos lists the items, adding the fact that he got them for cheap. Saitama is impressed by this and compliments him by telling him that he's mastered the trick to buying stuff, even admitting to missing out on some AAA batteries at half price. Suddenly, the two encounter Sweet Mask who offers to meet up for a cup of tea tomorrow noon as he wants to discuss something in person. Genos refuses the offer, believing that Sweet Mask is talking to him, but it is then revealed that he was speaking to Saitama.

The next day, Saitama and Sweet Mask are sat on a table in a cafe. A waiter approaches them and asks what they would like; Saitama orders a coke and Sweet Mask orders a lemonade, but Sweet Mask orders a ginger ale for Saitama instead of the coke, which irks him.

Later, Sweet Mask has lunch with Saitama and tries to teach him how to be a good hero. Saitama ignores most of what Sweet Mask has to say, so Sweet Mask decides to move somewhere else to continue his talk. They walk to a carnival and sit in a Ferris wheel cabin. Now able to speak in secrecy, Sweet Mask reveals his past to Saitama. He explains that he was born an unsightly human, so he adhered to strict moral principles to compensate for his ugliness. He started working as a hero, but his overwhelming loathing for his looks resulted in a transformation that turned him into a monster with a beautiful face. Sweet Mask then tells Saitama that he is the one person he found worthy of carrying on his legacy and becoming the ideal hero. Saitama turns down the offer and jumps out of the cabin to meet Genos.

Suddenly, a commotion on the fairgrounds catches Sweet Mask's attention. The cause of the ruckus is Pesky Clown, who had killed several guards that had attempted to stop him. The monster swings his mallet to hit a civilian, but Sweet Mask shows up and stops the attack. The two engage in combat. Sweet Mask has the upper hand at the start of the battle and destroys three of the monster's life balloons. However, the monster draws power from the attention of the crowd and transforms, becoming powerful enough to overpower the hero. Sweet Mask then decides to unveil his monster side in order to defeat Pesky Clown.

Story Impact

 * Sweet Mask reveals his past to Saitama.