Webcomic / One-Punch Man

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"I became the hero I had always dreamed of being. But how can it be that, even though I should be satisfied, I feel so empty...?"

A terrible monster suddenly attacks Z-City without warning. Many innocents are killed instantly, and more continue to be wiped out by the terrifying fiend with each passing minute. But when all seems lost, a lone saviour appears and destroys the monster with a single punch. Who is this mysterious protector? He is...

Just someone who's a hero for fun.

One Punch Man is a 2009 Japanese Web Comic created by the artist and writer ONE. The series is largely an Affectionate Parody of Shounen Superhero stories, bringing many tropes standard to the genre to their logical conclusion to ridicule their over the top melodrama or general silliness.

Saitama is an unemployed Salaryman turned part-time Superhero who is so powerful he can defeat any adversary in one hit. He's not very pleased about this, since it means he has no more challenges left in his life. But despite this, Saitama continues to follow his (now utterly mundane) dream, encountering Mutants, Cyborgs, Ninjas, Humanoid Aliens, Supernatural Martial Arts masters, Psychics, corrupt Super Teams, Kaiju, Sea Monsters and just about everything else you can imagine along the way.

The series has been wildly popular, with the ongoing webcomic being adapted into a manga drawn by Yusuke Murata of Eyeshield 21 fame, an English serialization of said manga in Viz Media's Weekly Shonen Jump, a drama CD, a Fall 2015 Anime adaptation, and several OVAs from December 2015 on.

An English dub of the series by Viz Media began airing on Toonami on July 16, 2016.

One Punch Tropes:

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    Tropes A-D 
  • Abandoned Warehouse District: There's an entire region of town which, for some reason, the monsters always attack; so, unsurprisingly, nobody lives there anymore. It's Saitama's neighborhood, and it's implied that powerful monsters attack there so often specifically because they've heard how strong he is and want to fight him. To the point that an entire monster organisation has made their base there.
  • The Ace: Genos is patient, intelligent, self-sacrificing, and a terrifyingly skilled fighter with a strong sense of justice. All this means he's pretty much playing the eternal Straight Man to Saitama's lackadaisical approach to heroism, although ultimately Saitama is still far stronger.
  • Adaptation Expansion: Murata's version compared to One's original webcomic. The anime adds even further scenes that were in neither comic.
    • To give an example: in both the webcomic and the Murata redraw, when Boros' ship arrives and devastates A-City, not a single mention was given to what happened to all the people who used to live there, and in the chapters that follow, it's all-too-easy to assume that its whole population was simply wiped out. The anime however devotes several scenes to show that, yes, there were survivors, and the Hero association spared no expense to make sure they were rescued and secured — it's just that most of the action was centered on the S-class heroes on the ground and Saitama's battle with Boros in the mothership itself.
  • Adaptation Distillation: At the same time, the anime removes some references pertaining to arcs after Boros' arc, save for some cameos for the characters. For example, they removed Genos' reference of the blizzard group's newbie crushing in episode 7. Also they didn't adapt the extra chapters, which caused a little problem as to how Pri-Pri-Prisoner and Sonic escaped from prison.
  • Adaptational Attractiveness: Given the source's artstyle, this is bound to happen to everyone save for a few examples.
  • Aesop Amnesia: Genos has a bad habit of underestimating his enemies and getting taken off guard, usually losing a limb during the process. He even lampshades that no matter how many times it bites him in the ass he keeps doing it.
  • Affectionate Parody: Of superhero comics and shounen manga.
  • Alien Blood: Copious amounts of it in the last episode of the anime when Amai Mask mercilessly slaughters the harmless aliens who survived the destruction of Boros' ship.
  • All Just a Dream: The subterraneans' invasion and Saitama's epic fight against them. The real subterraneans conveniently happen to be invading just as Saitama wakes up, but turn out to be much less impressive opponents.
  • All There in the Stinger: The anime adaptation does this quite frequently. One notable example is in Episode 5, when the stinger shows Genos asking to move in with Saitama and giving him rent money in order to convince him. Anyone who misses this stinger, or who hasn't read the webcomic or manga, will be confused as to why Genos is suddenly living with Saitama in Episode 6.
  • An Arm and a Leg:
    • Mosquito Girl rips off one of Genos' robotic arms in her first attack. Then a few seconds later she realizes that Genos ripped off both her legs at the same time.
    • Iaian loses his left arm to one of Melzagald's attacks.
  • Anime Theme Song: THE HERO!! by JAM Project.
  • Arm Cannon: Genos has blasters built into both his hands.
  • Armor Is Useless: Averted. Boros was able to survive Saitama's first attack because his armour protected him, subsequently shattering to pieces afterwards. Boros declares, however, that the armour was actually a Power Limiter.
  • Art Evolution: ONE's webcomic, while still rough around the edges, has seen a notable improvement in terms of visuals over time. While still not up to the level of the redraw, the more recent chapters look far more professional than the early ones to say the least.
  • Art Shift: In Murata's version, Saitama is usually drawn incredibly half-assed, in stark contrast to the ridiculous level of detail given to almost every other character and background, reflecting his attitude toward everything. Whenever he starts taking things seriously and acts like a badass though, he's drawn in the detailed style. Tornado seems to adopt this tendency of normally being poorly-drawn herself when she's angry/pouting.
  • Artifact Title: As the series progresses, more enemies (such as Boros and Garou) appear that Saitama has to punch more than once to defeat. They still pose no problem to him though as his initial punches are just his "normal" ones and he can still One-Hit KO them with moves from his "Serious Series" (and in the latter's case, he never really intended to kill him anyway).
  • Asshole Victim: Quite a few suffer from this, such as the random thief who goes around looting when the Mosquito Girl shows up, only to be killed by a gigantic swarm of mosquitos literally sucking the lifeblood out of him. And anyone dumb enough to kill, threaten, or attack civilians, or the heroes attempting to defend them when Saitama is around.
  • Atomic F-Bomb: Saitama lets out a frustrated one after he defeats Vaccine Man in the first chapter.
  • Attack of the 50-Foot Whatever: Beefcake is a bodybuilder who grows into a giant monster after his scientist brother makes him special steroids.
  • Autobots, Rock Out!: Whenever you hear this guitar chug, Saitama's about to kick some major ass.
  • Award Bait Song: "Kanashimi Tachi Wo Dakishimete". A perfect way to end the first season of the anime after the epic fight against Boros. Also, considering Madhouse tendencies to not continue an anime series (although the second season is later confirmed)... thank you, goodbye indeed.
  • Badass Gay: Puripuri Prisoner, an okama and the 17th ranked S-class hero.
  • Badass Grandpa: Bang AKA The Silver Fang, the 3rd ranked S-class hero.
  • Badass Longcoat: Zombieman wears one.
  • Badass Moustache: The hero Spring Mustache is apparently named after his, admittedly very stylish, mustache. Bang also has an awesome old man-style mustache.
  • Badass Normal: In the second issue, we get a flashback to the time before Saitama gained his incredible strength, when he fought a crab monster with nothing but normal human speed, strength, agility, and a necktie. He won. Also, a fair amount of high-ranking heroes are simply average-looking people who happen to have Charles Atlas Superpower.
  • Bald of Awesome: Saitama. He used to have Shounen Hair, but it fell out from all the training.
  • Bald of Evil: A gang of bald terrorists eventually appear, making people fear anyone who is bald, including Saitama, who decides to defeat the gang simply to make his life easier.
  • Barehanded Blade Block: Saitama can do this with one hand. Then SNAP THE BLADE. Hell, he doesn't even need to use his hands because he can do the same with his ''TEETH!''
  • Be Careful What You Wish For:
    • Regular guy Saitama wished to become a hero who could defeat any enemy with one punch. After years of training he got what he wanted, which led to an existential crisis.
    • Saitama also promised that if they both successfully registered as superheroes (because he didn't want to go alone), he would make Genos his official disciple. He soon regrets the decision.
    • Boros was an unstoppable alien conquerer who found himself in the same predicament as Saitama, and followed a prophecy that he would find his equal on the distant planet of Earth. In his fight with Saitama, he is forced to use all his powers and trump cards, and he even gets Saitama to use a couple "serious" attacks. However, after his defeat, he can tell that Saitama was still holding back, and dies feeling unsatisfied with the battle.
    "It was as if...throughout the entire battle...not once...did you bare your fangs...heh. Prophecies really can't be trusted. You are too strong."
  • Beauty Equals Goodness: Zigzagged. Genos is probably the most morally sound of the characters considered to be particularly handsome in-universe, whereas, despite being a high ranking hero, Handsome Kamen Amai Mask is a merciless Anti-Hero who kills any monster he can get his hands on regardless of their crimes. Speed of Sound Sonic is essentially neutral, but is antagonistic most of the time. Ugmons invoke this, becoming powerful monsters through their ugliness, whereas Pig God is at first glance a Fat Bastard but can be considered one of the most heroic S-class heroes.
  • Beef Gate: Non videogame example. The Hero system allows the top ranked member of each class the opportunity to move up to the next class.
    • Amai Mask intentionally sits at the top of A-class to keep anyone he considers undeserving from getting into S-class.
    • Top ranked C-class hero License-less Rider is an unintentional one. He refuses to go into B-class for personal reasons (probably because he is severly underpowered even for B class) but his presence still generates a standard that must be surpassed for a hero to rise from C-class; because he has the personality and Heroic Resolve of an Ideal Hero, but no powers, a hero must have some kind of combat ability to surpass him and reach B class.
    • Similarly, Fubuki is top of the B class due to her Inferiority Superiority Complex and desire to command the other B-class heroes instead of just being one A-class hero among others, although Saitama might be slowly talking her out of it.
  • Berserk Button:
    • Saitama doesn't take missing his Saturday special sales very well.
    • Mosquitoes seem to drive him crazy, especially when he can't kill them.
    • Long drawn out exposition sets him off pretty quick.
    • Doing damage to his apartment also counts.
    • And most of all, don't make fun of his baldness.
    • Calling Tatsumaki a brat will guarantee a brutal beatdown from her.
  • Beyond the Impossible: Metal Knight was able to fix and improve City A in seven days what the Hero Association assumed would take a minimum of 10 years. With that he even improved it by reinforcing the Headquarters so it could house A Rank heroes and have roads all over the country. The Association is both amazed and terrified of Metal Knight for pulling this off.
  • Bishounen:
    • Sonic wears makeup, has long hair, and is very pretty and slender. Many readers have mistaken him for a woman.
    • Lightspeed Flash, the S-class hero, is also very pretty and with long white hair.
    • The top A-class hero, Handsome Kamen Amai Mask, is a pretty boy idol.
    • Facially, Genos also fits, but his other features are pretty masculine.
  • Bishounen Line: Once Mosquito Girl absorbs all the blood her mosquitoes have collected, she becomes more human in appearance.
  • Blade on a Stick: A-class hero Stinger's weapon of choice.
  • Blessed with Suck: Saitama wanted to be a superhero who could blow away evil with a single punch... which as it turns out was incredibly boring. Now battling villains and monsters are about as exciting as a trip to the grocery store to pick up a gallon of milk.
  • Blood Knight: Saitama. He first became a hero when he rescued a child from a monster after being fired from his previous job with no hope of getting a new one. He felt such a rush after this first heroic rescue that he dedicated himself to becoming a hero. At one point he has a dream about being attacked by an army of monsters that actually CAN give him a challenge. The next morning, he goes up against enemies similar to those in his dream, but not as strong; he's left horribly disappointed.
  • Bloodless Carnage: When Sonic decapitates the Paradisers in the anime, only the last one who dies partially off-screen is shown bleeding, despite the fact that 20-30 people in front of him lose their heads too - there's literally no blood from them, the heads fall off and they're dead. That's it.
  • Bloody Hilarious: In the anime adaptation, instead of being slapped through a building Mosquito Girl's body splatters on it, releasing all the blood she absorbed beforehand. It's enough to cover the whole side of a building and then some.
  • Body Horror: Mosquito Girl's victims are reduced to mummified husks when her swarm sucks out all their blood.
  • Bookends: Season 1 of the Anime adaptation begins and ends with an extremely threatening Mysterious Being showing up all of a sudden, outlining why all humans have to die, with Saitama one-punching them after their bragging and being very frustrated that was all it took. Especially in the last case, since he had just fought someone who could actually take more. Also, in that same episode wherein he dreamed he fought some worthy foes, dramatic music swelled and Saitama's heart beat, as if he's feeling some challenge once again... only this time it's Boros whose blood is pumping again, with the prospect of facing a truly worthy foe whom he could go all out with.
  • Boxing Lessons for Superman: Bang attempted this with Saitama and Genos. Neither went for it, the former because it would be pointless and the latter because he's of the "best offense is a good defense" mindset.
  • Bratty Half-Pint: Saitama had to deal one in a special chapter.
  • Bubblegum Popping: Saitama annoys the speaker at the hero seminar by chewing gum and then making a bubble so big it covers his whole face when it pops.
  • Bullying a Dragon: On two separate occasions, "Snake Fist" Snek and Tanktops Black Hole and Tiger try to bully or defame Saitama into quitting professional superhero work, only to quickly realize his insane power, which they all wrote off as a trick or joke is completely real.
    • Bang lampshades this as he observes Tiger and Black Hole's attempt. They could have gotten away with the attempt to shame Saitama (not that Saitama gave a damn), but Bang pretty much immediately declared that they were screwed the moment they attempted a newbie crushing.
  • Calling Your Attacks: Most of the heroes and villains have at least one.
    • Saitama sometimes pulls out the "Normal Chain Punch". On the rare occasion that he gets somewhat serious, he also has a lethal "Serious Series" of power moves.
    • Silver Fang teaches the "Water Stream Rock Smashing Fist" to the students at his dojo. His brother is master of the "Whirlwind Iron Cutting Fist". The techniques can be combined into the "Cross Fang Dragon Slayer Fist". After learning these and a dozen other "fists", Garou creates the "Monster Calamity God Slayer Fist".
    • Even Licenseless Rider has moves like "Justice Crash" and "Justice Tackle".
  • Cassandra Truth: When Saitama reveals the secret to his incredible power consisting solely of doing a lot of heavy strength and endurance training, none of the other characters believe it. Genos in fact attempts to claim it's a flat out lie, saying that no one could get as powerful as him just doing that.
  • Casual Danger Dialogue: Saitama regularly engages in small talk with villains or other heroes who happen to show up on the scene, as for him there's literally no threat and no stakes.
  • Challenge Seeker: Satama's driving motivation is to meet and spar with an opponent who will not drop dead from his trademarked One-Hit Kill punches. This inability to find a worthy opponent drives much of his boredom as a superhero.
  • Charles Atlas Super Power: Seems to be almost a law of physics in the setting:
    • Saitama became as strong as Superman through sheer physical training. Namely 100 push-ups, 100 sit-ups, 100 squats and running 10 km every single day!note 
    • Silver Fang Bang, Super Alloy Darkshine and Tanktop Master, and quite a few other heroes also apparently gained their own less extreme superheroic abilities through physical training.
    • Several monsters indicate they gained their powers or mutations by doing one thing obsessively, such as one guy turning into a crab monster from eating huge amounts of crab.
  • Chekhov's Gunman: The boy who Saitama saved in his Origin Story has a grandfather who's a multimillionaire and thus founded the National Superhero Registry. The grandfather founded it exactly three years ago after hearing how Saitama saved his grandchild.
    • Also, the House of Evolution. After the arc with them as the Big Bad, they completely disappear from the story. Until many chapters later, where it is revealed that Zombieman, the 8th ranked S-class hero, was one of their creations.
  • Clothing Damage:
    • In Chapter 6, Saitama has all his clothes blown off by the blast from one of Genos' attacks.
    • Puripuri Prisoner also inflicts this on himself whenever he fights, because his muscles are too huge for his prison uniform.
  • Comically Invincible Hero: Although during the comic's few more contemplative moments, he's also a Tragically Invincible Hero.
  • The Comically Serious: Genos doesn't acknowledge Saitama's weirdness one bit.
  • Constructed World: The whole series takes place on a Pangea-sized continent shaped like Saitama prefecture with city-states named after the alphabet, and that's just the beginning of its differences. See Crapsack World below.
  • Continuity Nod: Chapter 20 has the Hero's Organization investigating Saitama's neighborhood and finding all the damage from his previous fights, with the destruction caused by the giant in the B and D cities also mentioned.
  • Conveniently Empty Building: A lot of buildings in Z-City are abandoned. Letting heroes like Saitama destroy them while fighting there without consequence. Justified by few people living there due to how frequent monster attacks are. The section where Saitama lives and most of the fights take place in particular is completely deserted.
  • Crapsack World: Not noticeable due to resembling modern Japan, but if monsters appear and millions die on a daily basis, it can qualify as this.
  • Crippling Overspecialization: Several S-class heroes have no other abilties outside of smashing things. Metal Bat even seems to take pride in this fact.
  • Curb-Stomp Battle: Saitama's specialty.
    • Stinger did not even get a chance to fight back against the Sea Folk's king.
    • Neither did Licenseless Rider, or against anyone for that matter.
    • Garou gave one to the S-class heroes after becoming a Mysterious Being. Until Saitama appears, that is.
  • Cursed with Awesome: Despite Saitama's existential angst over having near infinite strength, his ability to defeat ANYTHING with a single punch has easily saved the lives of entire cities of people a hundred times over.
  • Cut Lex Luthor a Check / Mundane Utility: After being defeated, the head of the House of Evolution uses his talents at creating regenerating bodies to produce unlimited octopus tentacles... and opens up a takoyaki stand.
  • Cute Monster Girl: Mosquito Girl is pretty creepy looking at first, but it helps that she doesn't wear any clothes.
  • Dark Secret: The S-class "strongest man on earth" King isn't strong at all. He just happened to be saved by Saitama 5 times and received credit for it by accident. He didn't mention it because he didn't want to dishearten anyone and he closed his eyes when he was attacked so he didn't see the real hero take the monsters down. He's just a scared Otaku way over his head with terrifying presence.
  • Decompressed Comic: Very much so. Just read chapter 25, the entire chapter is just Metal Knight arriving and landing near Genos.
  • Decon-Recon Switch: Although there's still a lot of humor and deconstruction going on, many of the later characters (like Zombieman) play their roles entirely straight.
    • The story begins as a Deconstruction of superheroes and Story-Breaker Power, but also works as a traditional superhero story with solid morals.
    • Saitama, when push comes to shove, is heroic. The deconstruction lies in putting heroes through a "system" which has lower-ranking heroes meet quotas to even maintain their status as a hero. S-class heroes might not be sent in to a real trouble spot because the higher ups don't see the situation below for what it really is. The politics one has to go through to maintain your status is also examined. Despite being the strongest man in the planet, people can still manipulate the system to make you look like a jackass. The sheer improbablity of his strength leads people to question if Saitama's the real deal to begin with. The reconstruction lies in Saitama stepping up despite these hurdles, stating that you don't need any of that to be a real hero.
  • Department of Redundancy Department: Speed of Sound Sonic. As Genos puts it, "It's like saying a round circle".
  • Determinator: The main reason Saitama has become so strong is due to his ability to stick to his hellish workout schedule for three years in a row.
    • A later flashback chapter shows this may have always been the case as far back as age 12, where he kept chasing a man-sized mysterious being that stole his money from two bullies that were shaking him down until it knocked him out.
    • Licenseless Rider doesn't seem to have won a single fight in his life and yet he refuses to give up against enemies even he knows he has no chance against.
    • Metal Bat grows stronger as he recieves more damage. He attributes it to "Fighting Spirit!"
  • Disproportionate Retribution: Lampshaded when Saitama calls out a crab monster for trying to kill a little boy who drew nipples on its shell with permanent marker.
  • Dissonant Serenity: Saitama usually approaches his fights with a completely impassive, almost bored expression.
  • Does This Remind You of Anything?: Mosquito Girl loves those "hot, sticky juices" her mosquitoes collect for her.
  • Don't Call Me "Sir": Genos insists on calling Saitama 'teacher', and when Saitama tells him not to, he switches to 'master' instead. So 'teacher' it is.
  • Dude, Where's My Respect?: Invoked. In the aftermath of the Sea King's fight, we see Saitana getting an entire pile of hate mail from the people he saved...then we flash back to him deliberately acting like a glory-stealing, selfish Jerk Ass who did a Kill Steal on the Sea King to prevent a genuine Ungrateful Bastard from ruining the name of the heroes who tried to stand up to the Seafolk invasion-his hate mail is due to the citizens being pissed off at his apparent scheme, with the people who know it was an act genuinely praising him.
  • Dungeon Bypass: Genos attempts this with the House of Evolution by blowing up the entire building with one of his lasers without even bothering to step inside; but it's ultimately subverted, since the actual stronghold was underground.

    Tropes E-H 
  • Early-Bird Cameo:
    • Several monsters Saitama defeated in flashbacks show up as still images in episode 4 of the anime, before any of said flashbacks have been shown.
    • In Murata's version, you can see King among the bystanders while the Paradise group is destroying the golden turd.
      • He appears even earlier in the anime, at the beginning of the first episode, as the passerby who crosses the shot right before Vaccine Man's attack (though he's barely recognizable).
  • Electronic Eyes: Genos of course. They possess some kind of Search & Destroy feature. They also glow when he's fighting.
  • Empowered Badass Normal: There are strong hints that while Saitama thinks he got his power (and lost his hair) due to simple training, some unknown factor might have empowered him. He suffered strange pains when his training routine started to give him powers, implying some sort of transformation, and the end result were powers he imagined that superheroes have. It turns out he just had a stomach ache and tooth ache from eating a huge amount of candy an old lady he helped gave him as a reward for helping her out earlier in the week. Later on its revealed that Saitama did in fact gain his powers from his training. It turns out he broke his limiter by training past the point where he should have died, destroying his own bodies limitations and giving him limitless potential to tap into.
  • Epic Fail: During Fubuki's challenge to Saitama and his "Saitama group" (composed of Genos, Bang, and King) in the hopes of making Saitama join the Blizzard group, the challenge was to beat the opposing group in a video game, with the loser submitting to the winner's commands. While Bang and Genos were eliminated easily due to being novices. Saitama boasts about having played the video game before and would not lose easily. He ends up losing faster than both Bang and Genos.
  • Establishing Series Moment: The series tells you exactly what you're in for right from the start. A monstrous villain goes on a rampage, Saitama steps up, the monster boasts of its strength, Saitama does his thing, and finally Saitama immediately complains about how anti-climactic it was.
  • Event Flag: Lampshaded in the fight with Garou, when Saitama, who had been excited at the prospect of finally getting a decent fight, starts to get angry when Garou keeps hitting obvious "loser flags" with his hokey villain monologue.
  • Everyone Has Standards: Some of the S-class heroes were shocked to see Sweet Mask execute the alien survivors, who were tied up, on the spot because they were evil and did not deserve to live.
  • Exactly What It Says on the Tin:
    • The story of One Punch Man is the story of a man who can defeat anything with one punch.
    • Quite a few superhero names hit the nail on the head. Saitama's in particular is the unflattering "Caped Baldy".
  • Expecting Someone Taller: Standard villain reaction to Saitama.
  • Explosive Overclocking: Boros' Meteoric Burst
  • Facial Markings: Sonic has red/purple stripes under his eyes. Tank Top Tiger has tigerish markings.
  • Fail O Sucky Name: Many members of the Heroes Association. It's what happens when these things get decided by committee.
  • Faux Action Girl: Ring-Ring in the martial arts tournament arc. She's the only female fighter in the tournament, and in her introduction is mentioned as having defeated all other active female martial artists in her area. Once in combat on-panel, she falls easily to a minor male character who didn't even have to use his primary weapon.
  • Fearless Fool: C-class Rank 1 hero Licenseless Rider has tried to face down a horde of power-armored terrorists and a nigh-invincible monster that defeated multiple S-class heroes, despite having no apparent superpowers of his own (one of his named attacks is throwing his bike at them). He barely survives both encounters, but he's also one of the few people who realizes Saitama actually defeated the Sea King on his own.
  • Fighting the Lancer: The "Sparring" two-parter. Genos takes it very seriously.
  • Fish People: Ones calling themselves Sea Folk invade from the sea in Chapter 23. They're tough and numerous enough to warrant a full scale hero counter-attack.
  • A Friend in Need: Despite complaining about the way Genos follows him around, Saitama shows concern for him and even fights Asura Rhino on his behalf when he gets turned into "modern art".
  • From Nobody to Nightmare:
    • Garou, who goes from a nobody to becoming one of the strongest beings in the series capable of fighting against several S-class heroes and defeating them.
    • Saitama is an example of this himself. Going from a melancholic out of work Salaryman to a nigh unstoppable force of nature any supervillain or monster who knew what was good for them would be existentially terrified of.
  • Full-Frontal Assault:
    • Puripuri Prisoner "transforms" into Angel Mode by ripping his clothes off and fighting in the nude.
    • Beefcake rips out of his clothes when he grows to giant size and goes on a rampage.
    Saitama: Put on some pants, will ya?
    • Saitama himself also ends up defeating Mosquito Girl naked after Genos accidentally incinerates his clothes.
  • Fun T-Shirt:
    • Saitama seems to have a liking for them.
    • The redrawn manga has a penchant for these, with bystanders such as a little girl's shirt saying "School Child" or a man whose shirt reads "Ippan Zin"note 
  • Funny Background Event:
    • When our heroes must climb a mountain to get to the House Of Evolution headquarters, we see the path they took and a sign saying 'Beware of the Bears'... with an unconscious, bloodied bear lying right beside it.
    • One random panel in Chapter 19 has a crow with human arms and legs stealing a fishbone from a cat. It's actually shown that a couple of crows mutated after eating the remains of the Beast King.
  • Gaia's Vengeance: The monster that Saitama defeats in Chapter 1 wanted to wipe out humanity as punishment for "poisoning Mother Earth".
  • Gone Horribly Right: After three years of ruthless training, so intense and hellish that it made all his hair fall out at the age of 23, Saitama got what he sought: the ability to defeat any foe with one punch. He didn't realize just how boring that would be.
    • The hellish training aspect is played for laughs. 100 push-ups, squats, and sit-ups are barely afterthoughts to professional athletes (and they typically don't punch out skyscraper sized monsters). Running 10 kilometers every day is more difficult, but certainly not insurmountable depending on the pace.
  • Gonk:
    • Any of the family gifted with unfortunately large cleft chins.
    • Pig God, on account of his obesity.
    • The child Garou saved, mirroring the cleft-chinned kid Saitama saved.
    • Weaponized by the Ugmon, humans turned into monsters by intense feelings of jealousy and inferiority.
  • Gorn: The titular One Punch can reduce even the toughest of being to Ludicrous Gibs. The two times Saitama uses a multi-hit combo (called Consecutive Normal Punches), it liquefies every part of his opponent above the waist. But Boros got better.
  • The Greatest Story Never Told: Saitama eventually realized he isn't famous even though he's been saving the city as a hobby for quite some time. Turns out, he needed to be registered as a superhero to get credit. If you don't, the general public considers a "hero" as just a weirdo in tights.
  • Grievous Harm with a Body: Licenceless Rider ends up on the receiving end when he tries to hold back the Sea King.
  • Groin Attack: Saitama does this (accidentally) to a ninja. The ninja survives, though Saitama held back. He does it again in a special chapter, accidentally elbowing an attacker coming from behind in the groin (coincidentally, the same ninja he'd accidentally groin attacked before).
  • Hard Work Hardly Works: Averted with Saitama's training schedule. It's a brutal training schedule that is of the "Kill You Or Make You Stronger" variety. Said schedule has made him stronger than any other character out there. When he registers to become a full-fledged hero, while he did poorly on the written test, in the physical portion, he set records in every category.
  • Heroes "R" Us: What the so called "Heroes Association" is shaping up to be by most accounts. After the Monsters Association Arc had ended, said corporate business went into a desperate recruitment drive for new blood to refill the ranks. A great many skilled and well known potential recruits flatly turned them down due to how far the organizations standards had plummeted.
  • Heel Realization: Right after Saitama defeats him, Garou asks Saitama what he sees being a hero as and why he became a hero. Saitama replies that, for him, being a hero is just a hobby. Garou immediately flies into a rage ranting that a real hero isn't like that. This leads to Saitama stating that Garou must have had the image of an ideal hero in his mind all along which leads to Saitama's Armor-Piercing Response to Garou:
    "You settled on being a monster but what you really wanted to be was the hero".
    • This causes Garou shock and he sits in stunned silence as Saitama accurately starts to deconstruct his whole mindset and reasons for trying to become a monster with Garou quietly stating at the end:
  • Hero Insurance: Cities get leveled and destroyed all the time during the fights between the villains and heroes. Good thing Saitama doesn't have to pick up the tab to repair the damage caused during the fighting.
  • Hero Killer: Garou, one of Bang's former but still BEST students.
    • Although he never actually killed any heroes
  • Heroic B.S.O.D.: Saitama has a brief one when he realizes he's become too strong and can't enjoy fighting any more. Luckily Genos then turns up to make things interesting. Then he has another one when he realizes he's not famous.
  • Hollywood Cyborg: Genos; it's currently unknown how much, if any, of his body is still organic.
    • A rogue cyborg that destroyed his hometown is who Genos is looking for at the start of the series. Minor characters Armored Gorilla, Jet Nice Guy and Armored Clerk are also cyborgs.
  • Hopeless Boss Fight: Saitama is a inversion; the hero is the one that can't be defeated instead of the villain. He also respects the willingness of others to engage in fights like these to protect others, or from a sense of duty. Notable examples include Licenseless Rider's stand against the Sea King, and Charanko challenging Garou by himself.

    Tropes I-L 
  • I Am Not Left-Handed: Saitama rarely puts any effort into fighting because of how powerful he is; the rare person that can stand up to him (i.e. Boros and Garou) face the "serious style".
  • I Was Having Such a Nice Dream: Saitama's epic and exhilarating battle against the subterraneans is cut short by his alarm clock.
  • Idiosyncratic Difficulty Levels: The Hero Association's disaster levels are a non-video game example:
    • Wolf: Appearance of a being or group that might pose a threat.
    • Tiger: Threat to an unspecified, large number of human lives.
    • Demon: Threat to a whole city or its functionality.
    • Dragon: Threat to multiple cities.
    • God: Threat to humanity.
  • Idiot Hero: He's not so much an idiot, but Saitama is very unperceptive about certain things and while it seems he got through school, he is still a little Book Dumb sometimes. Sometimes, like in a flashback, he beats the monster of the week without even realizing it, he misses some facts or easily inferred pieces of knowledge, he didn't know about the hero ranking system despite people talking about it around him, he forgets people's names a lot even if he's been told them several times, and he often misinterprets information that he hears or gets sidetracked easily. Much of this has to do with how lazy he is. The biggest offense, though, is that he never realized that it's impossible for people to get as strong as he did through strength training. The only thing that he knows is that he did it somehow and he still believes that anyone else can succeed in the same way despite being told how impossible that is.
  • Impossibly Cool Clothes:
  • In the Name of the Moon: "Riding the bicycle of justice, Licenseless Rider enters the scene!"
  • In-Series Nickname: Every hero is given one by the Hero Association. The names usually describe their appearance or powers.
  • Inaction Sequence: Frequently defied and deconstructed, as Saitama doesn't like overly long speeches. And whenever someone tries to pull this off, Saitama tends to put a stop to it either verbally or physically. A non-subtle 'jab' at mangas/animes that love padding.
  • Instant Fanclub: Genos accumulates an off-screen one thanks to a popularity poll which deems him one of the most handsome (and therefore highest ranking) heroes. He was given the nickname "Cyborg Prince" by his fans in-verse.
  • Invincible Hero: Deconstructed. Saitama was quite possibly created as a Take That to these kinds of heroes, showing how after a while Victory Is Boring both for the audience and, in his case, the characters themselves.
  • Jaded Washout: Saitama, before becoming a hero. Even as a kid, he didn't feel his future looking up. And even after becoming a hero, once he reached his current Invincible Hero status, his outlook on life is back to square one.
  • JAM Project: Did the 2015 OP. And it is glorious.
  • Jerkass Has a Point: That Ungrateful Bastard at the end of the Sea Monster Arc may have said some disrespectful things about the heroes but he does have a point when he talks about the heroes' classes not meaning a thing as some heroes, like Fubuki and especially Saitama, are proven stronger than the class they are placed in.
  • Kaiju: Gargantuan humans, bugs, and sea creatures.
  • Killed Mid-Sentence: Kamakyuri (one of monster from the House of Evolution) attempts an ambush by crashing down through the ceiling of Saitama apartment. He begins to introduce himself, but is killed instantly by an irritated Saitama, who demands he pays for the damage.
  • Leave Him to Me: Genos attempts this, but is interrupted when Saitama plants both opponents in the concrete.
  • Let's Get Dangerous: any time Saitama is drawn with actual detail, it's a cue that the fight is basically over.
  • Lightning Bruiser: The Sea King is described as this when he fights against Sonic.
  • Loads and Loads of Characters: New characters have been introduced at a steady pace, but starting with the sea monster invasion arc over a dozen new A and S-class heroes are introduced. Some awesome, some crazy, some Crazy Awesome.
  • Lost in Translation: Some jokes didn't translate that well to the western audiences due to cultural differences. For example, Saitama saying that he won't let the kid get killed due to Japan's declining birth rate might fly over the heads of western people.
  • Lower-Deck Episode:
    • The "Rumor" two-parter, focusing on an outside investigation into rumors about Saitama's neighborhood.
    • One special chapter features a B-class hero who finds himself in over his head.
  • Ludicrous Gibs: The end result of any suitably powerful blow, such as humans being struck by monsters or Saitama punching anything at all. The anime opening features Saitama with fist upraised, casually walking away from the rain of blood-soaked entrails that used to be a monster. He later punches a giant demon so hard in the fist that the demon's flesh vaporises off his body, leaving behind a flailing skeleton.

    Tropes M-P 
  • Made of Iron
    • Whatever training Saitama took didn't just make him insanely strong, but also gifted him with incredible endurance, so much so that hitting him can actually harm his opponent.
    • Hammerhead, the leader of the bald terrorist group, has an unusually thick skull which allows him to survive a lot of head trauma.
    • Super Alloy Darkshine's basically a lower-level Saitama in this regard.
  • Major Injury Underreaction:
    • After Genos' entire arm is ripped off, he only glances at it blankly for a moment before going back to his fight.
    • After his brush with Asura Rhino:
    Genos: That didn't work.
    Saitama: Dude, he cracked your face open!
  • Me's a Crowd: The scientist who founded the House Of Evolution made numerous clones of himself to assist with research. They get turned into a Red Shirt Army.
    • Black Sperm
  • Mistaken for Gay: When Saitama is informed that a scientist has "taken a great interest in your body" (for experiments), he replies that he doesn't swing that way. Genos corrects him.
  • Monstrosity Equals Weakness: Saitama claims that Garou has never been weaker after he changes into an even bigger mysterious being while trying to beat him, As opposed to the smaller more human monster he was before.
  • Mook Horror Show:
    • Asura Rhino's experience when he senses how powerful Saitama is. All the more terrifying because Asura Rhino was indicated to be the most powerful being encountered so far (stronger than even the hundred foot giant from an earlier issue), and has never feared anything in his life, but in seconds, he goes from being a Smug Super to screaming in fear and immediately breaking off his attack.
    All my instincts are screaming at me... Get away from him! He's dangerous!
    • The crew aboard the spaceship that the Dark Matter Thieves arrive on Earth in get to witness this firsthand when Saitama manages to board their ship hovering well above the city. He single-handedly slaughters most of its crew, and damages large portions of their ship. And once he kills several of their elite fighters, it only further terrifies them. Similarly, Melgalzald gets a taste of this as well after the ship's Death from Above attack gets negated completely by Tatsumaki, who then proceeds to turn the shells around, and flings them back onto the alien ship.
  • Mugging the Monster: Anyone that attacks Saitama out of the blue, not realizing that he's so far above them that they're ants by comparison.
  • Mundane Made Awesome:
    • Saitama can defeat anybody with a single punch. This means that should he deign to pull out such simple moves as a combo that anybody can master (The Normal Chain Punch, for example), better start praying for his opponent. Taken Up to Eleven when used in conjuncture with his "Serious Series" moves, such as "Serious Consecutive Side Hops" and "Serious Table Flip".
    • The two tasks which Saitama finds the most daunting? Swatting mosquitoes and finding a lost cat.
    • An entire faction of heroes, reaching all the way to S-class, is dedicated to Tank Tops.
  • Mundane Utility: Genos can use his blasters to dry off dishes.
  • Ninja: "Speed of Sound" Sonic.
  • Noble Demon: Garou to a tee, oddly enough being that he doesn't take to nor condone underhanded tactics, engage in mass slaughter other Mysterious Beings are known for and act more or less as a fair and honorable combatant. Also he didn't take too kindly to a sleazy Hero's Association coordinator using his questionable ties to certain celebrity personnel in order to hit on some groupies as said corporate lowlife can attest.
  • No Challenge Equals No Satisfaction:
    • Despite how many battles he ends up fighting, the fact it only takes a single blow for Saitama to defeat any opponent has left him rather listless.
      Saitama: I became the hero I had always dreamed of being. But how can it be that, even though I should be satisfied, I feel so empty...?
      Saitama:: Having overwhelming power is pretty boring....
      • Boros, leader of a group of space raiders, became bored with galactic conquering due to how easy it became. Saitama, however, finds the idea of rampaging across space just because you're bored moronic.
  • No Sell:
    • Thus far nothing has been able to harm Saitama, he's had bruises from Boros and Garou but that's it. He doesn't bother dodging most attacks because they won't do anything to him anyway.
    • Happens to Genos when he underestimates his enemy.
  • Non-Powered Costumed Hero: Many of the lower-class registered heroes seem to have no superhuman powers at all, Licenseless Rider being the most obvious example (although his powers may have been overshadowed by the supervillains he faced).
  • Non-Standard Character Design: Normally, Saitama looks like he's drawn very simply, in comparison to the detailed designs of everything around him. Sometimes he shifts to a more serious-looking action style.
  • Not So Different:
    • Saitama has a brief moment of this after seeing Hammerhead do the same ridiculous windmill attack (spinning his arms) that he used to do as a kid.
    • During his fight with Boros who, like him, became the most powerful being on his planet and lost interest in life. Saitama would SURELY NOT kill his boredom in the destruction of other planets.
  • Not So Well-Intentioned Extremist: Hammerhead and his followers claim to be going on a rampage against the wealthy and powerful because of the corruption of the wealthy, but in reality most of them, especially Hammerhead, simply don't want to have to really work for a living. Hammerhead changes his ways after most of his followers are killed by the bloodthirsty ninja Sonic, (an encounter that Hammerhead himself barely survives) and he is spared by Saitama.
  • Now That's Using Your Teeth: Can muscle training do this much? Really?
  • Off with His Head!: Sonic's favourite method of attack. "Why is everyone collapsing all of a suddennnnnnnnnnnnn..."
  • Offhand Backhand: To a giant bug that had just mopped the floor with 5 registered heroes.
  • Oh Crap!:
    • Asura Rhino, who is the first villain to be able to accurately gauge Saitama's power. Before doing so, he was supremely confident in his invincibility, but then his survival instinct kicks in.
      • In the same part Saitama suffers a massive one when Asura Rhino enters Carnage Mode for a week, due to the fact of having forgotten that day was Saturday and he was missing grocery deals, thus he one-punched Asura in regret of having forgotten that.
    • Also, anything rated threat level Demon tends to cause a Mass "Oh, Crap!" for everyone in the city.
    • The previously smug superhero candidates suffer a collective one when they realise just how powerful Saitama is.
  • One Dialogue, Two Conversations: While the Blizzard Group was out earning money to get a decent car, Blizzard returns with one third of the amount in a short amount of time while the rest of the group were scraping by with their part time work. After they questioned how she was able to do such a thing her dialogue makes it sound like she prostituted herself, until she explains she was capturing criminals for their bounties. Then It is revealed this is what she originally ordered her group to do in the first place, but mistook her order as to get part time work.
  • One-Hit Kill: This is the premise of the story and basically Saitama's super power. He's so ridiculously strong that he can kill anything in one punch, even when he's holding back.
  • Overshadowed by Awesome: Most professional heroes get this treatment given just how ineffectual they can be against monsters that the higher ranks or Saitama can obliterate without breaking a sweat.
  • Parody Sue:
    • Saitama, especially early on, is a parody of the God-Mode Sue, being too powerful in comparison to those he faces. However, it's shown that he's incredibly disillusioned by his immense power and values finding a Worthy Opponent over really being heroic. As the story moves on, he starts to lose his Sue status thanks to being forced to fight seriously on a couple occasions, although even that is described in-universe as him barely trying and depending on the reader he may gain more traditional Sue attributes due to becoming more like the Ideal Hero.
    • Most other traditional Sue elements get handed to Genos. He's handsome, rich, popular, talented, makes his hero debut as class S at age 19, broods and talks at length about his Dark and Troubled Past, and gets away with causing a lot of damage to his surroundings. What puts him on the parody spectrum is that for everything he has going for him, he's usually the one getting his ass kicked, primarily due to his own recklessness.
    • invoked Garo is a parody of Villain Sue, being an unstoppable force that keeps getting more powerful with no real explanation and trounces everyone until Saitama comes along. However, his status as the most powerful antagonist faced yet is effectively neutered due to how he's never killed anyone besides monsters and was never planning on it. Garo was never an actual threat and halfassed trying to be a villain.
  • Person of Mass Destruction: Any individual rated threat level Demon or above qualifies for this; Demon-level threats threaten an entire city, Dragon-level threats threaten multiple cities, and God-level threats threaten all of mankind.
    • Genos is sometimes this, blowing up large buildings with his Arm Cannon early on at the drop of a hat. Tornado of Terror also manages this by way of her namesake Psychic Powers. She's even destroyed Saitama's house just lifting the Monster Association out from under the ground.
    • Saitama. His punches completely destroy monsters, leave massive holes in buildings, and are strong enough to destroy meteorites that a Macross Missile Massacre and Genos' Wave Motion Gun failed to damage.
  • Petting Zoo People: The members of House Of Evolution are all these, including a mosquito, a lion, a slug, a frog, a mole, and a cyborg gorilla.
  • The Pirates Who Don't Do Anything: The amount of heroes who actually behave like superheroes is very low. Silverfang at one point bemoans how many of the S-class heroes are Power Level obsessed and don't act at all heroic after Tornado ends up scrapping Genos over a petty insult, and Licenseless Rider ends up holding top rank in the C-class heroes despite being an unpowered Muggle because he's actually willing to act superheroic.
  • Police Are Useless: Zigzagged and Discussed. In a side chapter in the redraw, Saitama is brought into a police station by officers suspicious of him (e.g. out wandering around during a working day, blood on his hands, living alone in an abandoned area) and because he vaguely resembles an image of a criminal in the area. Despite this the officers are shown to be Reasonable Authority Figures who remain professional despite their clear suspicion, and during their questioning the chief laments how the police are now effectively seen as this due to the flashier and cooler Hero Association overshadowing them in the publicís eye despite all the legitimate work they do for society. Itís later shown that while the police are in fact no match for threats at Demon level and above, their criticisms of the Hero Association as corrupt Glory Seekers arenít unfounded and the chief later admits that Saitama was a true hero after he defeated the monster and let the police have the credit to prevent them from being humiliated in the public eye.
  • Power at a Price: Played with; when he reappears later on, the head of the House of Evolution says that Saitama's power came at a great price... he became bald. Immediately afterwards, though, he plays it straight, indicating that as he sees it the real price of Saitama's power is the way it has alienated him from the rest of humanity.
  • Power Levels: Of a sort, for both heroes and villains. Registered heroes rank in four groups (C-class, B-class, A-class and S-class), and have numerical ranks within those. These are of course not accurate measures of their strengths as, after registering, Saitama starts out at a low point in C-class despite having set records in every physical test. Most human villains seem to be ranked similarly, at least as far as the class system goes. Monsters meanwhile are measured with "Disaster Levels", which denote their power in terms of scope of possible destructive capacity (Wolf, for unknown; Tiger, threat to an unspecified large number of human lives; Demon, threat to a whole city or its functionality; Dragon, threat to multiple cities; God, threat to humanity).
    • A special chapter has Child Emperor create a device that can calculate a person's physical strength numerically. As a benchmark, the average C-class such as Red Muffler was 100. B-classes like Darkness Blade were several hundred, A-classes like Stinger and Great Philosopher were over 1000, a regular human was 22, a bear was 905 and a Demon-level monster was 6999. The device can't give readings for people who are weaker than an average person. It also can't read Genos since he's mostly mechanical and when it tries to read Saitama it breaks and can't give a reading, leading Child Emperor to assume he's out of shape (while assuming the same result from King means his power exceeds 9999). Fubuki's psychic powers also can't be quantified (she comes in at 19 physically, regular human level), Child Emperor concluding that the device is pointless.
  • Power Makes Your Hair Grow: Inverted. Saitama's training made all his hair fall out.
    • Boros plays this straight however with his hair getting longer and longer until his hair is identical to a Super Saiyan 3's hair.
  • Punch Clock Hero: Saitama mentions that he doesn't really believe his heroics will have much of an effect upon the world and he only does them because they bring him excitement; or at least they used to.
  • Pursue the Dream Job: Saitama quit being a run-of-the-mill salaryman and trained for three years so he could take up superheroism as a hobby.

    Tropes Q-T 
  • Reality Ensues
    • Being a hero doesn't mean you can neglect daily necessities, such as buying groceries and taking a piss.
    • Cracking a giant meteor with a single punch? Awesome. Its falling debris destroying the city? Not so much.
    • When Mumen Rider takes on the Deep Sea King, Rider has a sudden burst of Heroic Second Wind, complete with a "World of Cardboard" Speech that drips of Heroic Resolve, and even gets a crowd cheering him on. Deep Sea King still flattens Rider with one hit.
    • The series as a whole showcases just how much damage a superpowered being could really cause when he's not following a comic code.
    • The anime adaptation of Boros' ship destroying A-City includes a scene of a memorial for those who weren't lucky enough to survive the attack.
  • Real Place Background: Apparently, Saitama's apartment does exist somewhere within Saitama Prefecture. City Z is in fact based on locations within the Saitama Prefecture. Even the whole continent is the shape of Saitama Prefecture!
  • "The Reason You Suck" Speech: Garou delivers these to the S-class heroes after curbstomping them.
  • Relax-o-Vision: Used in Chapter 15 after a particularly... painful attack, the scene cutting to the words "Please wait a moment" over a picture of Ghibli Hills.
  • Resurrective Immortality: Zombieman, whose power is that he can't die at all and will regenerate no matter how many wounds he gets.
  • Ridiculously Average Guy: Were it not for Saitama's baldness, he'd have no distinguishing features whatsoever, but at the same time, his baldness makes him even more nondescript.
  • Robo Speak: Armoured Gorilla originally talks like this, but drops it after he's defeated and admits he was only trying to sound cool.
  • Running Gag:
    • Genos mistakenly thinking Saitama would desperately want his hair back or being generally tactless about the subject of his baldness.
    • Genos losing at least one limb in a fight.
    • Kids calling Saitama (who's 25) "uncle", which he bitterly denies.
    • Saitama and Sonic having a duel? It's somehow gonna end with Sonic on the receiving end of a Groin Attack.
  • Scene Transition: Several of the manga chapters are just one scene drawn out over a dozen or so pages, with scenes flowing into each other so fluidly that you could make an animation out of them.
  • Scenery Gorn
  • Screw This, I'm Outta Here!: Sonic's reaction to Puri-Puri Prisoner's Angel Mode.
    Sonic: "...He's naked. And he's definitely no angel. Nor is he human. Nor do I want to watch. I'm out."
    Puri-Puri Prisoner: "No one has ever seen my Angel Mode and lived to tell about it."
    Sonic: "All the more reason to leave."
  • Serial Escalation: Saitama's fight with Boros. It starts with the latter surviving one of Saitama's punches, followed by Boros getting his arm punched off, healing it back, going into his Super Form, kicking Saitama to the moon, Saitama jumping back, the two of them exchanging combo attacks, Boros regenerating from a splatter of pulp, and finally firing a massive Kamehame Hadouken which Saitama deflects with his first "Serious Punch".
  • Shoot the Shaggy Dog: This is the fate of almost every villain in the story.
  • Shout-Out:
    • To the Shounen and Tokusatsu stories it mocks.
    • Several to Anpanman: in Japanese the titles are similar (Onepanman/Wanpanman), Saitama's costume is based on Anpanman's, and the name of the series' first villain, Vaccine Man, riffs on Baikinman ("Germ Man"), Anpanman's main villain.
    • Vaccine Man also looks a lot like Piccolo.
    • Smile Man has a uncanny resemblance to El ChapulŪn Colorado, of all things. He even has a hammer as a weapon and similar costume.
    • The cover page to chapter 3 features a suspiciously Godzilla-like kaiju.
    • Genos' backstory is similar to several Kamen Riders, especially those of the Showa Era. There's also the Licenseless Rider, who rides a bicycle to battle. His hero name in Japanese - Mumen Rider - is another pun on Kamen Riders.
    • The Anime adds one by showing that Asura Rhino's Asura Mode transformation is colored purple with green lines, much like Eva-01. For bonus points, it's also an out of control berserker mode.
    • One monster is a ginormous insect with a human face in the middle of its insect head, and one of the heroes who shows up to fight it is a scarred swordsman clothed all in black. Unlike Guts, he gets his ass handed to him.
    • In the anime rendition of Puri-Puri Prisoner's fight with Sea King, the sequence when initiating Angel Style bears a very strong resemblance to Sailor Moon's Transformation Sequence. Minus the part where a battle suit appears... but not minus the part where his original clothes disappear.
    • The title pages of several manga chapters contain Shout Outs. Chapter 6's has "I'm gonna change" (Cutey Honey's Catch Phrase) while Chapter 13's has "Aku Soku Zan" (Hajime Saito's motto).
    • Episode 10 of the anime sees Tatsumaki fighting another suspiciously Godzilla-like kaiju.
    • The entire sixth special (where the plot is about the murder of Zombieman) to Detective Conan with Child Emperor act like Conan Edogawa (well, both have the same seiyu).
    • During the Martial Arts Tournament arc, while Saitama is inspecting the contestant roster you may notice a contestant by the name of Rossie who fights under the "psycho-analysis style".
  • Shut Up, Hannibal!: After landing a hit on Saitama, Boros takes a break to gloat about his superior regenerative power that should eventually grant him victory. Saitama interrupts him, clearly showing that he's neither fazed by the blow nor impressed by the talk.
  • Slasher Smile: Sonic is often sporting one, which he refers to as a bad habit.
    You just want to try your techniques on me. I can tell by that child-like smile on your face.
  • Sliding Scale of Villain Threat: Referenced in the show itself with the "Disaster levels". Wolf level is only a potential threat. Tiger is Personal, Demon is City, Dragon is everything above City until Global, which is designated as God level. The series itself plays with this, though, as the first monster encountered in the manga, Vaccine Man, is a dragon level threat, the second highest. Another one of these doesn't appear until 10 chapters later.
  • The Social Darwinist: The House Of Evolution was made for the purpose of evolving humans beyond their current limits, since the genius creator found everyone he met to be inferior to him. He gives up when he meets Saitama, an ordinary man who surpassed his limits with sheer determination alone.
  • Sorting Algorithm of Evil: Played with like most typical Shonen tropes. The day to day monster and villain attacks vary greatly in threat level, but the monsters fought at the end of their respective sagas seem to legitimately increase in power as time goes by:
    • The Subterranean King, failing to live up to the one in Saitama's dream, comes across as rather weak and is unceremoniously dealt a One-Hit KO (though since he didn't get a chance to do anything it's possible he was stronger than he looked).
    • Asura Rhino gets a greater build up, being talked up as the House of Evolution's best fighter and defeating Genos without going One-Winged Angel, but is still killed with one punch.
    • The Deep Sea King tears through a number of heroes, including S-classes Puri-Puri-Prisoner and Genos, before being killed with one punch.
    • Boros is the first to survive one of Saitama's normal punches, and even his Consecutive Normal Punches, and is also the first opponent to get Saitama to use a "Serious Series" attack. The next monster of course gets killed in a single punch
    • Garou basically beat all of the heroes he faced during his "Hero Hunt" besides Saitama, including most of S-class, and several Demon/Dragon level monsters before becoming a perfect monster. It's ambiguous as to whether he was actually stronger than Boros in the end though.
  • Soundtrack Dissonance: The ending song. It's a cheery romantic song in contrast to the heavy metal opening and rock soundtrack.
  • Spotlight-Stealing Squad:
    • Done deliberately in group artwork, where Saitama is often pushed to the side and cooler-looking characters like Genos are made the most immediately noticeable.
    • A good example is the Volume 2 cover, which consists of Genos looking good in the foreground and Saitama crammed into the corner, looking stupid.
    • Invoked in universe where people tend to attribute Saitama's victories to the other, more appealing, heroes around him, leading to situations like King having all the fame Saitama should have while everyone thinks Saitama is a fraud
  • Status Quo Is God: Saitama is actually disappointed that his hair fell out. However, whenever Genos points out that Dr. Stench can easily replace it for him, he refuses... for some reason. It's never explained.
  • Stealth Hi/Bye: In the Boros attack, itís revealed by Mr. Exposition that the building is made of the strongest stuff there is. The next time Genos turns to Saitama, Saitama has already left the building BY JUMPING THROUGH THE CEILING to go fight the aliens. The anime adaptation shows that this made no detectable sound.
  • Stylistic Suck: The crude art of the original webcomic is deliberate. ONE can draw very well when he wants to.
    • In both the webcomic and the manga, Saitama in particular is generally drawn in a much more simplistic, lower-quality style than everyone else.
  • Superhero Prevalence Stages: The prologue of the story starts in the Early stages of superheroes, when there's not that many and they're disorganized. The leap forward into the actual story shows a world in the Late stage where there's dozens of superheroes, a governing body controlling them, and villains whose sole goals are to challenge the heroes' authority.
  • Super Registration Act: The National Superhero Registry. Only registered members receive fame and fortune for what they do; those that don't sign up are pretty much just costumed lunatics in the public eye.
  • Taking You with Me: Subverted. Genos primes his self destruct as Mosquito Girl is about to kill him, hoping to take her out in the blast. Saitama splatters her across the wall right before, removing the need.
  • Teach Me How To Fight: The already ridiculously strong cyborg Genos starts following Saitama around calling him 'sensei' and asking to become stronger. When Saitama tells him how he achieved his current strength, however, Genos is kinda disappointed.
  • Theme Music Power-Up: The anime has an uplifting battle theme that is played not just for the heroes, but also for some villains' hopeless but determined struggles against Saitama. Licenseless Rider gets a solemn Dark Reprise of this theme when he challenges the Sea King.
  • There Is No Kill Like Overkill: Just one punch leads to death and dismemberment, which is often accompanied by a look of mind numbing boredom from Saitama.
  • Too Dumb to Live: Snek hears that the new C-class hero he had been berating was only C-class due to an appalling written test score and that he had gotten a perfect score in the physical exam by a ludicrous margin. Snek decides to "Rookie Crush" this newbie to keep him from getting cocky. Saitama promptly destroys him. He's not the only one dumb enough to try such half baked stupidity where the jerks in question realized too late that was a really, really, really dumb idea.
  • Training from Hell: Parodied. Saitama does 100 push-ups, 100 sit-ups, 100 squats, and 10 kilometers of running every single day with no breaks. Said training was what caused him to go completely bald. Note: This doesn't even begin to approach the level special forces soldiers or professional athletes train at.
  • Tournament Arc: Saitama joins a martial arts tournament disguised as Chanranko using a wig.
  • A Twinkle in the Sky: Mosquito Girl is slapped aside by Saitama and dies from it, most likely because she was knocked through at least one building in the process.

    Tropes U-W 
  • Underestimating Badassery: Any time Saitama gets in a fight, he's dismissed as a weakling, either due to his rank or his unassuming appearance. Most don't live to regret that, and the few that do know not to mess with him from then on (except "Speed-O'-Sound" Sonic, who just won't let it go).
  • Ungrateful Bastard: Despite Saitama's heroic efforts of destroying the gigantic meteor and dividing it into smaller pieces just so the city would still be intact, a lot of the Z-City citizens are pissed, at first because they think he was just taking credit from the S-class heroes who couldn't destroy it, and then when it's established that he did destroy the meteor, they're mad because of the damage its debris caused. He does however counter with his very own awesome "World of Cardboard" Speech.
  • Unlikely Hero: Though the decision to become a hero was Saitama's own, his main motivation seems to be boredom and he often gets frustrated by the ridiculous situations he finds himself in. Consider how most heroes start their stories. Most of them were for revenge or to get acceptance.
  • Unskilled, but Strong:
    • Genos. His answer to most problems is overwhelming firepower and force; luckily he's got a lot.
    • Saitama might appear to be this but he's not. Sure, he wins most of his fights through brute strength and speed, but he's got enough control to destroy a mountain behind his opponent without moving them, and enough precision to jump back to Earth from the moon. It's not that Saitama lacks finesse—he just doesn't need it.
  • Unusually Uninteresting Sight:
    • Saitama wears a bright jumpsuit and a cape would attract the attention of many people while Genos is a cyborg with black sclerae and robotic arms yet no one bats an eye to them. In fact Genos can mingle with a crowd without being found out. Justified, as the Hero Association exists and there are costume wearing heroes so people are used to seeing these heroes.
    • Deconstructed with Saitama. He barely even acknowledges a monster before or after he kills it and most of the time, even forgets about it completely. Because of this, he doesn't report in his heroism to the Hero Association, leading to one of the main reasons he is still at such a low rank.
  • Unwitting Pawn: During the Hero Killer arc, the eponymous Hero Killer Garou meets a kid who loves heroes and pretends to be a fellow fan in order to get information on where he can find certain heroes.
  • Up to Eleven: Saitama's strength training is absurdly simplistic and played for laughs, but it prepared him to defeat skyscraper-sized monsters with less effort than Superman does...somehow. The other characters who have heard his explanation comment on how flat-out impossible his strength is when compared to what he claims to have done.
    • Not simply his strength, but his speed is so far beyond super-human, it is ridiculous. During the first confrontation with "Speed of Sound" Sonic, Sonic spends half a chapter trying to intimidate Saitama by ricocheting randomly off the trees around him at superhuman speed. When Sonic asks if he can even see him, Saitama instantly turns his head towards him (with a disturbingly motion-blurred face) to ask if he can go home now.
    • Equally Saitama is lazy beyond anything seen in a shonen, to the point where half the time, the artist can't even be bothered with shading him in.
    • Happens literally in the fight against the Sea King. Ten fighters- Stinger, Lightning Max, Puri-Puri Prisoner, Speed of Sound Sonic, Jet Nice Guy, All Back-man, Buzz-Buzz Man, "Snake Fist" Sneck, Genos, and License-less Rider- are all beaten until the 11th fighter, Saitama, comes by and one-shots the beast.
  • Vagueness Is Coming: "The Earth is in trouble!!!", according to a fortune teller with a 100% track record for accuracy. Essentially, the greatest disaster of the age is due to strike before the year is out. However, since Shibabawa died before she could elaborate on said "trouble", nobody actually knows what it is or when exactly it'll happen.
  • Villainous B.S.O.D.: Garou seems to have one of these after being defeated by Saitama
  • Wall of Text: Genos' backstory is delivered this way as a joke. Ever wonder what an origin story sounds like without a flashback? Now you know.
    Saitama: YOU IDIOT!!! TELL IT AGAIN IN 20 WORDS OR LESS!!!
    • We get another one explaining the National Superhero Registry, presumably also provided by Genos for Saitama's benefit.
  • Wham Episode: In Chapter 107 of the webcomic, on the downside, after the Garou incident, the Hero Association has lost faith from the public, Saitama unintentionally damaged the reputation of Metal Knight (by destroying his defenses he built for the Hero Association) and Tatsumaki (his fight with her did serious damage to the cities they fought in causing complaints about her) so now the Hero Association will increase their surveillance on them, several heroes are retiring, including Bang, and Child Emperor gained a distrust for the adults in the Hero Association. On the upside, Fubuki finally decides to move up to A-Class and Zombieman wants Dr. Genus' help to remove his limiter.
  • What Measure Is a Non-Human?: Saitama never hesitates to kill monsters—even one that was running away—regardless of intelligence, yet he lets human criminals live, including a guy who killed a whole building full of people for no reason. This later becomes a major element of the Garou plot arc, as he's a human who thinks it's unfair that the heroes always win and the monsters always lose. He ends up following the trope to a T anyway, which is why both the monsters and Saitama refuse to consider him an actual monster.
    • It should be noted that one major element of the series is that many monsters start off human and then become monsters usually due to some sort of obsession. The idea seems to be that these kinds of monsters are Always Chaotic Evil but if the monstrous form can be shed, such as with Psykos or Garou, then they were just "playing monster" and can be redeemed.
    • It should also be noted that Saitama doesn't kill anything that hasn't seemed to kill anyone or if they are like him in a way that he deems them redeemable. For example, he let the kelp monster escape perhaps because he didn't actually kill the two A-class heroes that he fought and was simply looking for a good fight. He also didn't kill Hammerhead despite him having his men punch down a skyscraper note , but he may not have known about that. We do know that Saitama spared him because he saw Hammerhead as the type of person he could have been if he took the wrong path. He was also going to let the Beast King and his buddies live if they apologized, but the Beast King murdered two of his allies and the Demon Mole retreated without saying sorry so he took both of them down. He ended up sparing their ally, the cyborg gorilla, because he apologized and answered his questions.
    • Played for drama with Handsome Kamen Amai Mask, who feels no remorse for anything that either resembles a monster or identifies as a monster, ruthlessly executing unarmed aliens and a rampaging caveman the association wanted him to bring back alive, as well as demanding that Garou not be left alive even after he'd reverted back to human, claiming them all to be "evil" and describing his own actions as "justice" because of this.
  • When All You Have Is a Hammer: Most of the S-class heroes are only really good at cutting/bludgeoning/punching stuff, so even when some of them encounter a Blob Monster, they're stuck futilely doing their thing because the literally only other option would be to stop fighting it. At least until Metal Bat discovers its weak point, allowing them to eventually harm it in a meaningful way. Saitama also falls into this category, of course, though the fact his metaphorical hammer would make the Goldion Crusher look like a rubber mallet tends to make up for it.
  • Whole Episode Flashback: Several of these, exploring Saitama's life before the story began.
  • Worf Barrage:
    • Several heroes do this against the current Monster of the Week, only for it to either do no damage, or the bad guy has a Healing Factor which negates everything they just dished out.
    • The bad guys are also subjected to this when fighting Saitama, only for their own attacks to barely do anything to him. For example, attacks from the Sea King that seriously injured several heroes earlier barely moves his head.
    • Hilariously parodied when Saitama is unable to kill a single mosquito despite slapping and hitting it several times. He then manages to kill their queen with a simple slap when she was about to finish off Genos.
  • The Worf Effect
    • Virtually every hero and villain gets Worfed. A is beat by B, who is beat by C, etc etc in a continually escalating battle of badassitude, and whoever is the mightiest gets to be one-punched.
    • Genos, despite being considered very powerful by a lot of characters, tends to be defeated quite easily by named villains. While normally this would serve the purpose of demonstrating how strong said villain is, and thus a potential worthy opponent for The Hero, Saitama knows better.
    • The Sky King attacks the Heroes' Association headquarters, referencing the Underground King (18 pages) and the Sea King (200 pages), implying that this is the beginning of an arc. Total time until he's Worfed? 7 pages.
  • World of Badass: Superheroes are incredibly common here, so much so that no one acts surprised when insanely strong guys in silly costumes turn up day after day to battle the forces of evil. However, while there are a lot of 'heroes' in this country, most of them are not at 'heroic' level. C to B-class heroes handle threats that most soldiers/policemen can handle. Most of the threats that currently come into the world are usually impossible to handle unless it's by an A or S-class hero and even they are sometimes not enough.
  • "World of Cardboard" Speech: A very effective example is done by Licenseless Rider, when he's in a hopeless fight against the Sea King.
    Licenseless Rider: No one expects much from me... They think a C-class hero won't be much help. I know that better than anyone. I'm not good enough for Class B. I'm weak. I know that much. No one has to tell me I have no chance of beating you. I already... know that! And yet, I must try. It's not about winning or losing! It's about me taking you on right here, right now!

    Tropes X-Z 

Alternative Title(s): One Punch Man

http://tvtropes.org/pmwiki/pmwiki.php/Webcomic/OnePunchMan