One-Punch Man — Chapter 3

One-Punch Man Chapter 3 introduces the disastrous consequences of Fukegao's ambition to create the strongest man through science. After completing his Ultimate Steroid-Biceps King formula, Fukegao convinces his younger brother Marugori to drink it, triggering a violent transformation where Marugori's body swells enormously. What begins as celebration quickly turns to catastrophe when Marugori grows too large for the laboratory, bursting through the ceiling and trapping Fukegao under the rubble. The brothers quickly embrace their new roles, with Fukegao declaring himself the brains and Marugori the brawn, united by a dream to conquer Earth and rule as kings. That dream immediately becomes a nightmare for ordinary people as Marugori rampages through a town, destroying it in a single punch and killing tens of thousands. With Fukegao riding on his shoulder, they move toward the next town, prompting authorities to declare a demonic disaster level emergency evacuation as the giant heads for City B. The panic that follows is palpable, with crowds fleeing, crying out, and fearing the end of the world while Fukegao laughs and urges more destruction. One-Punch Man Chapter 3 is especially effective because it contrasts massive scale violence with a strangely intimate sibling dynamic. Marugori is not simply a monster, but a younger brother who only wanted to be strong, and his grief when Fukegao is killed shifts him from conqueror to avenger. His boast that he is now the strongest man rings hollow when he admits that overwhelming strength feels empty and boring, a confession made to the calm stranger who listens and pats him. The chapter ends bleakly with City B destroyed, leaving the cost of unchecked power and reckless experimentation fully exposed.