Saitama and the Hero Association of the anime series One-Punch Man have faced many monsters, aliens and robots, but their greatest threat is a human, Garou. Introduced in the final scene of the Season 2 premiere, Garou actively hunted superheroes with surprising efficiency, using his extensive martial arts training to cut a destructive path against the hapless heroes.
Unlike many of Saitama's opponents, Garou survives the events of the season to live to fight another day. Now, we're taking a quick look back at Garou, the self-proclaimed human monster and nefarious hero hunter that singlehandedly put the Hero Association on high alert.
Flashbacks interspersed throughout Season 2 of One-Punch Man revealed that Garou had grown up as a bullied, ostracized young boy. After watching monsters defeated constantly by superheroes on television as a child, Garou sympathized with the behemoths rather than the heroes and swore to dedicate his life to avenge the monsters he identified with by training to hunt heroes.
Garou began training in martial arts with an elite fighting school, developing blindingly fast speed, immense endurance and an impressive amount of strength. The dojo was overseen by Bang, the Hero Association's top martial artist, and Garou quickly became Bang's star pupil. Upon reaching a satisfactory level of power for himself, Garou singlehandedly defeated all of his classmates and most of his teachers before being defeated by Bang and barely escaping. At a gathering of criminals organized by the Hero Association as an impromptu truce, Garou learns of a prophecy that the monsters would overwhelm the heroes and eradicate humanity, which led him to put his lifelong revenge plot into motion.
Garou begins his rampage by completely annihilating all the assembled criminals and heroes, except for the hero Sitch, who was tasked with spreading word of his villainous arrival. Saitama begins targeting C and B-class heroes, including Tank Top Vegetarian and Mumen Rider, before defeating Tank Top Vegetarian's mentor Tank Top Master, his first S-class target. After barely defeating the hero Metal Bat, Garou is approached by the newly revealed Monster Association to join their ranks by transforming into a monster through the consumption of a monster cell but turns them down to go his own way.
While recovering from back-to-back defeats against Watchdog Man and Saitama, Garou is ambushed by eight mid-level superheroes. Initially throttled by the ensemble, Garou begins to goad the group by playing off their insecurities causing them to overreact and grow sloppy. From there, Garou is able to pick off each of the team one-by-one before barely emerging victorious despite being exhausted and wounded before the fight even began.
As with many of his opponents, Saitama is completely underestimated by Garou when the two first meet as Saitama searches the city for a wig to disguise himself and infiltrate a martial arts tournament. Assuming Saitama to be a low-level superhero, Garou karate chops him only for the hero to return the favor after mistaking Garou for a mugger. Immediately rendered unconscious, Garou would awaken sometime later, developing a bout of amnesia to forget the encounter.
After being beaten by Watchdog Man after failing to counter his unpredictable fighting style, Garou spots the world's top-ranked superhero King and attempts to attack him. However, he's dismissively countered by Saitama,. who is unable to recognize Garou as the notorious hero hunter and the man he beat earlier. Later, after enduring brutal beatings by Genos, Bang and his brother Bomb, Garou is rescued at the last second by the Monster Association's Phoenix Man, who brings the hero hunter to the organization's leader.