WARNING: The following contains spoilers for "Metal Bat," the fourth episode of Season 2 of One-Punch Man, available now on Hulu.
Ever since the start of the second season, Garou, One-Punch Man's mysterious new villain, has relentlessly hunted the heroes of Z-City to ensure a prophesied monster apocalypse comes to pass. Dubbing himself "The Human Monster," the reasons behind Garou's bloody vendetta have been kept a secret. However, at the start of the fourth episode, his background and villainous motivations stand revealed.
The prologue to the latest episode of the acclaimed anime shows Garou as a child watching footage of superheroes saving the day from attacking monsters. Rather than cheer on the heroes, however, Garou feels sorry for the monsters, who are mercilessly killed by the heroes time and time again. Visibly upset watching the death of a behemoth, Garou vows to become a human monster and stop the heroes from battling the creatures once and for all.
Following the opening credits, Garou is revealed to still be recovering from his first fight with Saitama. As disoriented as he is after enduring a blow from the bald superhero, Garou may not be able to recognize Saitama when the two fighters inevitably have their rematch. Instead, the self-proclaimed human monster decides to resume his mission to rid the city of superheroes, undeterred by the unexpected setback, further underscoring the obsession he has held since childhood.
While Saitama himself doesn't play a particularly major role in the latest episode, he does inadvertently learn more about the principal antagonist from an old associate of Garou's. Following his newfound interest in the world of martial arts, Saitama disguises himself as Charanko and enters a local tournament audaciously named Super Fight. Saitama meets fellow entrant named Sour Face, who had studied martial arts alongside Garou. The villain, it turns out, had abruptly stopped his training after feeling he had attained enough power, and easily defeating all his classmates before being defeated by Bang and disappearing.
From this prologue and Sour Face's own history with Garou, the villain's motivations have been revealed to be one of sympathy for monsters. As an apparent social outcast, Garou felt a kindred connection to monsters rather than fearing them like his peers. Their constant death at the hands of heroes led Garou associate the growing superhero population with those that presumably tormented him during his childhood. Studying martial arts was only ever a means for Garou to live up to his promise of avenging all the monsters he watched die growing up.
From the start, One-Punch Man has featured a never-ending influx of monsters, each more fearsome and intimidating than the last; the most recent episode alone had five different beasts stage their own attacks on the city. Despite this, the greatest monster of them all isn't a born monster at all, but rather a put-upon human that quietly swore vengeance watching the creatures he felt connected to get killed from afar.
Highly trained in martial arts and defeating every hero he has crossed paths with, with the notable exception of Saitama, Garou now targets Metal Bat as his next S-class victim. But with Saitama learning more about the world of martial arts himself, albeit from a place of genuine curiosity rather than an attempt at gathering strategic knowledge about his enemy, Garou may soon find himself outclassed once more when he and Saitama do battle in earnest.
Produced by J.C. Staff, new episodes of One-Punch Man debut every Tuesday on Hulu.