Rumored Monster Arc

Fifth in the series and the second arc of the Hero Association Saga, this short chapter holds the distinction of being the first story crafted for the manga rather than adapted from the webcomic. It centers on the Association's staff parceling out territory to its heroes and dispatching two of them to chase down whispers about an abandoned part of the city.

The Hero Association's leadership gathers to review incident reports from across its territories. Acting on rumors surrounding a derelict stretch of Z-City, they send Spring Mustachio and Golden Ball to investigate. The pair run into the monster Kombu Infinity, who overpowers them and clarifies that it is not the being behind the rumors, having simply decided to play the part of a monster for its own amusement.

The creature then crosses paths with Saitama, who strips away its kelp-like hair to use in a bowl of soup. Genos assumes his mentor intends the seaweed as a remedy to regrow his own hair, a suggestion Saitama flatly rejects.

The chapter drops the first hint that a Monster Association exists. It also establishes that the Hero Association assigns individual heroes to guard specific cities, naming which hero watches over each district and noting that some towns are still under repair from an earlier rampage. On the sidelines, Sneck keeps tabs on Hammerhead as the reformed terrorist hunts for a job.