Superheroes battling monsters form the foundation of One-Punch Man. Beyond the high-powered action, the series introduces a range of characters whose appeal extends far beyond their combat abilities. While some possess strength, others stand out due to their distinct personalities, quirks, and the roles they play in shaping the story.
Since the show’s premise leans heavily into humor, many heroes are built around eccentric gimmicks that set them apart. Some exist purely for comedic relief, while others have deeper connections to the revealing events, making them essential to the plot.
From comedy to chaos, every hero brings something unique to the story (Photo: One Punch Man/Madhouse)1. Metal Knight
Equipped with an array of Iron Man-style weaponized technology, Metal Knight utilizes remote-controlled drones to annihilate monsters, placing him on par with Genos in terms of raw firepower.
However, an unexpected aspect of this so-called hero is that his true self remains unseen—he operates entirely through drones while keeping his actual location hidden. When interacting with others, he displays the cold demeanor of a scientist who views each encounter as an experiment rather than an act of heroism.
His presence within the Hero Association elicits both admiration and unease, as his detached approach makes it unclear where his true loyalties lie.
2. Terrible Tornado
Among the most formidable heroes in Class-S, Terrible Tornado ranks second within the Hero Association, standing as the elder of the psychic sisters. Her immense esper powers allow her to win battles effortlessly, which results in a detached, almost indifferent attitude toward combat, much like Saitama.
Unlike Saitama, however, her temperament is far less easygoing. During Season 1, as the alien invasion threatens the city, she takes charge with an abrasive and condescending approach, belittling her fellow heroes along the way.
Even in Season 2, when forced to step in to protect her younger sister, she exhibits more irritation than concern, treating the situation as an inconvenience rather than a personal mission.
3. Speed-o-Sound Sonic
Neither hero nor villain, Speed-o’-Sound Sonic operates as a lone force driven by one simple objective—defeating Saitama to avenge his humiliation. Unlike others who seek power for justice, survival, or personal ambition, his motivation is singular and unyielding.
This self-declared rival of Saitama proves to be a formidable opponent, showcasing speed so intense that he appears to be in multiple places at once. His abilities allow him to battle Genos on even footing in Season 2, hinting at the potential for greater feats in the future.
By consuming a monster cell, he attempts to enhance his strength, setting up an uncertain path that leaves fans eager to see what lies ahead.
4. Suiryu
Power serves different purposes for different characters, and for Suiryu, it is merely a means to secure a comfortable, undisturbed life. As the reigning champion of a prestigious martial arts tournament, he exudes a laid-back demeanor that mirrors Saitama’s, though his overconfidence blinds him to his limitations.
His encounter with Saitama provides an entertaining contrast, as his arrogance crumbles when he realizes that his formidable physical abilities have no effect on his opponent.
Even after his defeat, his role remains crucial, particularly in his confrontation with Goketsu, who tempts martial artists with monstrous transformations.
5. Watchdog Man
Dressed in a full-body dog costume, Watchdog Man appears more as a visual gag than a conventional hero. Yet, despite his humorous appearance, his abilities are nothing short of extraordinary. For much of the series, his strength is merely implied, as he is often seen sitting among piles of defeated monsters nonchalantly.
It isn’t until Season 2, when Garou challenges him, that his fighting style is fully revealed. Using a quadrupedal approach, he moves with inhuman agility and remains expressionless throughout the battle.
His prowess proves so overwhelming that Garou is unable to defeat him and later adopts aspects of Watchdog Man’s technique into his combat style.
6. Metal Bat
With his pompadour hairstyle and rebellious attitude, Metal Bat embodies the stereotypical Japanese delinquent. At first glance, his combat method seems straightforward—he wields a metal bat and swings with immense force, powerful enough to earn a Class-S ranking.
Season 2 expands on his character, revealing an ability to grow stronger as he sustains more damage, attributing this resilience to his indomitable “fighting spirit.”
Beneath his tough exterior, however, lies a protective older brother who refuses to fight in the presence of his younger sister, keeping a promise he made to her.
7. Hellish Blizzard
Hellish Blizzard, the younger of the psychic sisters, holds the highest position in B-Class, wielding considerable esper abilities. Despite being a registered hero, her motivations revolve more around maintaining her ranking as a symbol of status rather than a genuine pursuit of justice.
Determined to secure her dominance, she assembles a group of subordinates to prevent lower-ranked heroes from surpassing her. Though her approach is self-serving, she does rise to the occasion in Season 2, stepping in when the Monster Association attacks the city.
However, her intervention falls short, requiring her sister to come to her aid.
8. Silver Fang
An experienced martial artist with a seemingly unremarkable elderly appearance, Bang, known as Silver Fang, ranks among Class-S heroes. While his demeanor and role resemble that of a serious version of Dragon Ball Z’s Master Roshi, his abilities far surpass expectations.
Metal Knight fights from the shadows, but where do his loyalties lie (Photo: One Punch Man/Madhouse)Season 1 presents him as a mentor figure, though his guidance is humorously unnecessary for someone like Saitama. In Season 2, his involvement deepens as he confronts the consequences of training Garou, the main antagonist who once studied under him.
Despite his age, Silver Fang proves that his mastery of combat is enough to rival his former student.
9. King
Hints about King’s status as an elite Class-S hero appear throughout Season 1, but it isn’t until Season 2 that the truth behind his reputation is fully revealed. Contrary to expectations, he has no actual combat skills—his legendary status stems from mistakenly receiving credit for victories achieved by others.
His “King Engine,” rumored to be an ominous battle aura, is nothing more than the sound of his heartbeat racing in fear. Interestingly, the foundation of his fame can be traced back to Saitama, who once saved him from a monster attack, leaving him with the distinctive scar he now bears.
Over time, the two develop a laid-back friendship centered around video games, and despite his lack of strength, King manages to display moments of courage inspired by the stories he’s absorbed from manga and games.
10. Mumen Rider
While Saitama embodies limitless strength, Mumen Rider represents heroism in its purest form. Instead of pursuing strength for the sake of power, his focus remains on helping people in whatever way he can, regardless of his limitations.
Unlike Saitama, who grows frustrated by his unmatched strength and the lack of challenge in his battles, Mumen Rider persists despite knowing he cannot overpower his enemies. One of his most defining moments occurs when he stands against the Deep Sea King, enduring a brutal beating before Saitama steps in to finish the fight.
Even in Season 2, his commitment never wavers—he intervenes to restrain heroes like Tank-Top Master from crossing moral lines and even confronts monsters in a hospital while injured. Though physically weak, Mumen Rider embodies the unshakable resolve of a true hero.