Because surprisingly, there wasn't one.
People's names are written only in katakana without surnames, and locations are represented by alphabets like "City A" or "City B." Humanity is constantly plagued by disasters caused by various grotesque creatures collectively called "Monsters." Humans with high combat abilities, such as martial artists, cyborgs, and psychics registered with the private organization "Hero Association," deal with these threats as "Heroes" by saving lives and exterminating monsters.
A massive organization founded by the billionaire Agoni after hearing his grandson's story of being saved by a passing man during a monster attack. Surprisingly, it is a private entity. Three years have passed since its founding at the time Saitama and Genos joined. It primarily serves as a support organization to facilitate hero activities, providing funds for activities and living expenses, and arranging housing. It handles the command and communication for efficient monster extermination, as well as investigations into monsters and evil organizations, and the certification of disaster levels. To join the Association, one must pass a certification exam consisting of physical and written tests (the cutoff is 70 out of 100 points). Upon passing, heroes are given a "Hero Name" (similar to a code name or nickname) based on their characteristics, and they often address each other by these names. Heroes are ranked into S, A, B, or C-Class based on combat ability, social contribution, and influence. Even if weak, a hero can rise in rank with high social contribution; conversely, no matter how strong, a hero remains low-ranked without a track record. However, "S-Class" is an exception, selected purely based on "raw combat power."
A collective term for supernatural beings that harm humans; in other words, a name encompassing villains, monsters, and kaiju. Even if they are not humanoid or are robotic, they are generally referred to as monsters. Since Saitama reached adulthood, the number and ferocity of monsters have surged, which was the catalyst for the founding of the Hero Association. Monster disasters are treated as natural disasters in this world, with danger levels displayed in five stages. Disaster level does not strictly equal strength; defeating a "Demon" level does not guarantee an instant kill against a "Tiger" level.
Level "Below Wolf"
Combat Power: Can be easily driven away even by an unarmed civilian.
Level "Wolf"
Combat Power: Equivalent to 3 C-Class heroes or 1 B-Class hero.
Level "Tiger"
Combat Power: Equivalent to 5 B-Class heroes or 1 A-Class hero.
Level "Demon"
Combat Power: Equivalent to 10 A-Class heroes or 1 S-Class hero.
Level "Dragon"
A threat where the destruction of multiple cities is feared.
Level "Above Dragon"
A realm where only extremely limited individuals can cope; likely a "national-scale crisis."
Level "God"
A threat where the extinction of humanity is feared. While not explicitly stated, it is certain that no one besides Saitama could stand against it.
Level "Unknown"
Assigned to monsters whose disaster level cannot be determined, usually because they have just appeared.
An organization formed by monsters of Disaster Level "Demon" or higher. Based in a massive facility (referred to as a "shabby hideout" by Psykos) beneath the ghost town of City Z, they plot the destruction of the Hero Association and the extinction of all humanity. The members consist of a small, elite group of only 17.
Hero Name: Caped Baldy
Name: Saitama
Gender: Male
Age: 25
Height: 175cm
Occupation: Hero (B-Class, Rank 63)
Likes: Cabbage, seaweed
Genos's master, addressed as "Master" or "Sensei."
Personality: Ordinary and calm in any pinch. He is indifferent and moves at his own pace. He has a sense of justice and never yields to any situation. He seemingly doesn't care at all that his strength is acknowledged by almost no one except Genos. Appearance: Wears a yellow suit with red gloves and a white cape when active as a hero. He is self-conscious about his lack of hair. Combat Ability: Possesses transcendent combat power that surpasses even Disaster Level God. He defeats enemies in a single blow even when unmotivated. Note that he has no psychic powers; it is pure physical strength.
Hero Name: Demon Cyborg Name: Genos Gender: Male Age: 19 Height: 178cm Occupation: Hero (S-Class, Rank 16)
Personality: Cool and serious. While he harbors a desire for revenge from his past, he seems much calmer now. He respects Saitama and Dr. Kuseno, who turned him into a cyborg. Appearance: Characterized by blonde hair, black sclera, and yellow pupils. He is handsome. His body below the neck is covered in inorganic, cyborg armor. Combat Ability: High combat power due to body modifications. He is considered strong even among the S-Class and excels in kinetic vision, reflexes, and various other areas.
Hero Name: Terrible Tornado
Name: Tatsumaki
Gender: Female
Age: 28
Occupation: Hero (S-Class, Rank 2)
Sisters with Fubuki (B-Class) and cares for her deeply.
Personality: High professional consciousness and responsibility, but extremely proud. She prefers to solve things alone and is foul-mouthed. It's not that she doesn't trust others at all; she simply doesn't want to rely on their help. Appearance: Slender with a small, childlike physique and green, naturally curly hair with coiled ends. Wears a black dress with high slits. Combat Ability: Uses psychokinesis (telekinesis) as her primary means of attack. She can manipulate objects to float or fly at will and is often seen levitating herself.
Hero Name: Atomic Samurai
Name: Kamikaze
Gender: Male
Age: 37
Height: 177cm
Occupation: Member of the Council of Swordmasters, Hero (S-Class, Rank 4)
Has several disciples who are A-Class heroes.
Personality: Self-proclaimed hard-boiled humanitarian. He is quite confident and only acknowledges those he has personally seen to be strong. Combat Ability: Master of swordsmanship capable of delivering slashes far exceeding the speed of sound.
Hero Name: Child Emperor Name: Isamu Gender: Boy Age: 10 Height: 135cm Weight: 35kg Occupation: Student, Hero (S-Class, Rank 5)
Personality: A boy genius. He is constantly licking a lollipop to fuel his brilliant brain, but also makes childlike comments like asking if he can go home because it's time for cram school. Appearance: A small boy with brown hair and blue eyes, carrying a black school backpack. Combat Ability: Fights primarily using special inventions and numerous weapons hidden in his backpack, which are generally stationery-themed.
Hero Name: King Name: ? Gender: Male Age: 29 Occupation: Hero (S-Class, Rank 7)
Personality: On the surface, he is silent, calm, and skilled in negotiation. In reality, he is a kind-hearted but extremely cowardly person. Appearance: Muscular with three scars over his left eye. He always has a stern, intimidating expression. Combat Ability: Combat style is completely unknown; all that is known is that he is "strong."
Hero Name: Zombieman Age: Around 30s Height: 174cm Occupation: Hero (S-Class, Rank 8)
Personality: A lone wolf with a nihilistic way of speaking, yet he is one of the more cooperative and sensible members of the S-Class, showing consideration for those around him. He is calm and highly observant. Appearance: Short black hair, red eyes, and greyish skin like a dead person. Wears a coat and has a lean, muscular build. Combat Ability: Can recover from even fatal damage, possessing a body that is virtually immortal. He excels in battles of attrition.
Hero Name: Flashy Flash Name: ? Age: 25 Height: 172cm Occupation: Hero (S-Class, Rank 13)
Personality: Always maintains a cold expression and rarely smiles. He is very proud and takes absolute pride in his speed. Appearance: Handsome with long, light-colored blonde hair and blue eyes. Combat Ability: Uses his beloved sword, Instakill, in a combat style utilizing ultra-high-speed movement and powerful techniques.
Hero Name: Metal Bat Name: Bad Age: 17 Height: 168cm Occupation: Student, Hero (S-Class, Rank 15)
Personality: Rough-mannered and quick to pick a fight, behaving like a delinquent, but he deeply values his younger sister and his pet cat. He has good intuition and is a cool, blunt guy. Appearance: Black pompadour hair, wearing a modified school uniform. He has a sharp gaze but a well-featured face, resembling a Showa-era delinquent. Combat Ability: A straightforward brawling style using a metal bat. He targets weaknesses when facing powerful monsters.
Blast / S-Class Rank 1
Hero Name: Blast. Real Name: ?. Gender: Male. A mysterious hero who performs hero activities of his own free will and cannot be moved even by the Association. A psychic who manipulates space-time.
Silver Fang / S-Class Rank 3
Hero Name: Silver Fang. Real Name: Bang. Gender: Male. Age: 81. Height: 165cm. Weight: 55kg. Despite his appearance, he is a gentle and fun-loving seasoned martial artist. Founder of the Water Stream Rock Smashing Fist and a titan of the martial arts world alongside his brother Bomb.
Metal Knight / S-Class Rank 6
Hero Name: Metal Knight. Name: Bofoi. A mysterious scientist who remotely controls robots equipped with high-firepower weaponry.
Drive Knight / S-Class Rank 9
Hero Name: Drive Knight. Name: Zero. A hero characterized by a monocular mask and black armor. He engages in combat using "Tactical Transformations" that change based on the situation.
Pig God / S-Class Rank 10
Hero Name: Pig God. Gender: Male. A lethargic, obese giant who is always eating snacks. He can swallow monsters whole and has other unique abilities. He is as sensible as Zombieman despite his appearance. If he stops eating or exercises, he becomes a slim, handsome man.
Superalloy Darkshine / S-Class Rank 11
Hero Name: Superalloy Darkshine. Gender: Male. A power-type hero with a steel-like body that shines black from intense muscle training.
Watchdog Man / S-Class Rank 12
Hero Name: Watchdog Man. A man always wearing a dog suit with a silent, expressionless face. He has an excellent sense of smell and high power and speed.
Tanktop Master / Rank 14
Hero Name: Tanktop Master. Gender: Male. A power-type hero who has mastered the art of wearing a tank top. A man of character with a true hero spirit.
Puri-Puri Prisoner / Rank 17
Hero Name: Puri-Puri Prisoner. Name: ?. He breaks out of prison only to perform hero activities. He loves men and captures dangerous criminals to build his own harem.
One-Punch Man
The anime "One-Punch Man"
One-Punch Man Worldline
Regarding the worldline of the anime "One-Punch Man."
One-Punch Man
The story is primarily set in a city resembling modern-day Japan.
One-Punch Man
The world of One-Punch Man
The S-Class heroes have been gathered.

Puri-Puri Prisoner: (I want to use this chance to get closer to Genos-chan! โก)
Release Date 2026.08.13 / Last Updated 2026.09.17