Genos

Genos (ジェノス, Jenosu), is a 19 year old cyborg and the disciple of Saitama. He is always aiming to become stronger and fights for justice. Under the Hero Association, he is given the name Demon Cyborg (鬼サイボーグ, Oni Saibōgu) and is registered as an S-Class hero, at rank 14.

Appearance
Genos has an entirely mechanical body in the model of a handsome young man. His face and ears look like that of a normal human, made of an artificial skin material, and his eyes have black sclera with yellow irises. He has spiky blond hair. His eyebrows are usually portrayed as blond, but in the anime they are brown. He also has pierced ears. Genos wears normal street clothes and sleeveless tops and hoodies in order to allow his arms to transform without hassle. He has been shown to have many different sets of arms, with varying abilities and strengths. Notable examples of his various "arms" are those he used in his sparring match against Saitama and the arms he equipped to combat the meteor. Sometimes the arm sets he uses create a metal framing around his face, like those he used against the meteor and the Sea King.

Personality
Genos is an extremely serious character. He constantly strives to become stronger and pesters Saitama to train him frequently. Since becoming Saitama's disciple, Genos is very reverent and protective towards his "teacher", although he does express annoyance and disbelief at the mundane training regimen Saitama used to gain his powers.

On most occasions, Genos acts as a comic foil to Saitama's clueless antics, using a variety of special techniques, battle tactics and robotic upgrades to combat villains (and sustaining terrible damage in the process), only to be outclassed by Saitama with a single punch. Due to Saitama's incredible strength, Genos is led to believe that there is a secret to Saitama's power.

Despite their disparity in strength, Genos' diligence earns him greater recognition than his mentor. His superior acumen granted him immediate status as an S-Class Superhero within the Hero Association, compared to Saitama's C-Class designation. He also possesses seemingly vast wealth, enough to repair or upgrade his cyborg body and cover Saitama's rent on a regular basis.

He eventually mellows out, and he recognizes that this is due to Saitama's influence. He eventually comes to respect Saitama not just for his power, but also for his character. This was shown when Genos remarks on how similar Handsomely Masked Sweet Mask is to Genos's former self when Sweet Mask brutally dispatches a group of alien prisoners with no mercy.

Early life
At age 15, Genos was still a human being living a happy and peaceful life along with his family. One day, a crazy cyborg attacked their town and destroyed it, killing his family. Genos miraculously survived, but he wouldn't survive long alone in his ruined town if he wasn't found by Dr. Stench who passed the town pursuing the cyborg. Genos begged Dr. Stench to transform him into a cyborg, who complied. Genos was reborn as a cyborg fighting for justice and promised Dr. Stench that one day he would find and destroy the cyborg.

For the next four years, Genos traveled from town to town defeating monsters and evil organizations, but was unable to find the whereabouts of the cyborg.

House of Evolution Arc
While Mosquito Girl is in the middle of her rampage in Z-City, she notices that quite a few of her mosquitoes have died and looking down, she spots a form swarmed by mosquitoes. She sends more bugs at the form, but they are all blasted away, revealing Genos. He has a stern expression on his face and declares that he will eliminate Mosquito Girl. Genos then fires a blast at her, but she easily dodges his attack and dives at him, taking his arm in the process, but in return he takes out both her legs below the knees. Mosquito Girl then flies away and summons all of her mosquitoes to give her their blood. Genos says that her efforts are useless, but is concerned when he sees the amount of bugs gathering around her. As he is about to charge his laser, Saitama comes running out on the street. Genos warns the so-called civilian, but Mosquito Girl's swarm of mosquitoes comes crashing down on them in an instant. Genos releases his heat beam and burns all the bugs, while telling his foe that making them attack in one big chunk makes it far more easier to destroy them. He realizes that Saitama was still in the area, but is shocked to see that he is fine, with only his clothes burned.

Mosquito Girl, now evolved, rushes down and appears behind Genos, cutting him almost completely in half. Genos then spins around to attack her but she dodges and begins to attack him continuously to the point that he was about to blow himself up to kill her as a last resort. Before that can happen, Saitama ungracefully smacks Mosquito Girl in the face, sending her crashing through a building and into the distance, killing her. Genos, greatly surprised by this, asks Saitama his name and for Genos to become Saitama's disciple.

A week later, Genos shows up at Saitama's apartment, having been fully rebuilt, to discuss being Saitama's student. Genos rather long windily begins to tell Saitama about his past, but Saitama tells him to come back when he can sum his story up with a max of ten words. Sometime after, Genos simply asks Saitama to teach him to become strong like him. Saitama warns Genos that it's going to be tough and agrees to train him. But at that moment, Genos turns, saying that he senses a presence moving at high speeds towards them when Kamakyuri smashes through the roof, only to be swiftly killed by Saitama. Genos and Saitama leave the building to find Frog Man and Slugerous on guard. Genos tells his master that he will take care of them, but before he can finish his sentence, Saitama has already smashed both creatures head first into the ground. Then, Saitama unexpectedly gets dragged down underground until only his head is showing. Genos starts to rush to Saitama's aid, but Armored Gorilla suddenly bursts through the wall behind them.

Armored Gorilla then attacks Genos who easily stops the attack. He says that he needs to ask the creature some questions. He then notices Beast King approaching Saitama, who is still buried and goes to help him but gets grabbed by Armored Gorilla who he then blasts away, and starts to run to Saitama again. Armored Gorilla attacks again and Genos is forced to jump away. The cyborg reveals that he is affiliated to the House of Evolution. Genos recognizes the name and asks what they want of his teacher. Armored Gorilla doesn't reply and simply states the he must destroy Genos. Saitama is then shown taking out Beast King and Ground Dragon and approaching Genos who is standing on an incapacitated Armored Gorilla, having defeated him in an off-screen fight. After showing Armored Gorilla that Saitama has killed Beast King, he agrees to tell them whatever they wanted to know.

Armored Gorilla reveals the history of Dr. Genus and the House of Evolution. He summarizes that the doctor has taken interest in Saitama's body and Genus clarifies that he wants to use Saitama's god-like physique to build the new human. As they take off to the House of Evolution's base, Genos asks some last questions. He asks about the House's involvement with cyborgs and Armored Gorilla replies that he's the only cyborg of the organization. Genos is disappointed. Four hours later, Genos and Saitama have arrived at the House of Evolution's base. When they find it, Genos promptly destroys the building and part of a mountain in the distance. Saitama is surprised of Genos' quick actions and notices a hatch on the floor and rips it open before Genos and him head down into the lair.

As they're walking down the hallway, Genos notices several life forms, two of which are coming at them at high speed. Carnage Kabuto appears, carrying Dr. Genus, who then points out Saitama, identifying him as Carnage Kabuto's target. Carnage Kabuto then throws Dr. Genus to the side and smashes Genos against the wall. The creature challenges Saitama to a fight, and he agrees on the grounds that Carnage Kabuto made Genos look like "modern art." Carnage Kabuto then shows Saitama to a rather large room and they are about to fight, but Genos suddenly appears and blasts Carnage Kabuto. Genos then rushes at Carnage Kabuto and hits him with a barrage of punches, but it doesn't affect the monster and he smashes Genos in the face, throwing him into the ground and causing his face to crack and his left eye to fall out. Saitama catches him and says he'll handle the fight, but Genos, stubborn as he is, sends a devastating blast at Carnage Kabuto. However, the opponent uses his breath to blow the attack back and blasts Genos instead, causing Genos' hair to puff up into an afro.

Saitama gets serious and proceed to challenge Carnage Kabuto, but the latter stops his assault when he detects Saitama's abnormally high strength and questions Saitama about the source of that strength. Saitama decides to reveal the secret to his power and Genos is amazed and is eager to finally know, but inwardly questions whether it is wise to divulge the secret to his enemies. Saitama explains that it is simply the result of hard work and training and obviously, Genos doesn't buy it and is skeptical. He tries to persuade Saitama to let him know the real secret, but Saitama simply replies that it's just that. Carnage Kabuto goes berserk and pummels Saitama, but he unexpectedly delivers but one punch to the monster and destroys him. Genos and Saitama return home after this.

In the anime, officers of the Hero Association find the results of Genos' blast that destroyed the top eight floors of the House of Evolution and identify Genos as the perpetrator of that blast.

Paradise Group Arc
Genos only appears briefly at the end of the arc, when he reveals to Saitama that he is not famous because he never registered himself with the Hero Association. He tells the history of the Association to Saitama and they agree in getting them both registered.

National Superhero Registry Arc
Genos and Saitama sign up at the 6th official superhero certification exam center. After he finishes the physical and written exam, he is greeted by Saitama in the changing rooms. They agree on how both tests were super easy and that they'll probably get full points too. A hour later, they receive their scores, revealing that Genos received a perfect 100 and is certified as a S-Class hero, though he wonders what that is. Genos becomes enraged when he hears that his teacher scored 71 points ranking him as a C-Class. They are then told to go to a lecture hall for a seminar of the successful candidates.

As they arrive in hall 6, they are congratulated by A-Class Superhero Snek. He gives them some advice on being a hero and the rankings, though Genos isn't interested in it. As they leave the seminar, Genos is glad that he finally becomes a real disciple of Saitama and counts on his guidance, though Saitama isn't actually glad with it, and they part ways soon after.

The next day, Genos and Saitama appear around a mountain area, with Genos sporting new black mechanical arms. Genos checks his phone, stating they are at the last place of their respective classes and that they didn't receive hero names yet. He puts the matter aside and thanks Saitama for accepting his "unreasonable request". The two prepare for battle, though Saitama believes it to be a sparring match, however Genos will attack with everything he's got. Genos positions in a battle stance and aims his left arm at Saitama, ports of his arm opens revealing several cannons.

He fires a single massive beam at Saitama. As it reaches Saitama, he dodges it, however Genos immediately retaliates by dashing towards Saitama. He takes a hold of Saitama and crashes him to the mountain, punching several times across the wall of the mountain, but he soon realizes that he was attacking Saitama's after-image. Genos immediately detects that Saitama is running away and intercepts him by landing in front of him and firing a massive beam. Genos believes he hit and defeated Saitama, only to have Saitama poke him in the cheek from behind and proclaiming victory.

Genos becomes angry and attacks him, but Saitama jumps away unscathed. Genos then reminds Saitama the rules of the fight, one of which is to continue fighting until he is unable to. They continue the fight, in hoping that he will discover insights of Saitama's power, however Saitama shows impressive fighting prowess and lunges to punch  Genos, but instead flicks him and invites Genos to eat udon. Genos watches Saitama walk away, as he is still flabbergasted of the force of the last punch, that destroyed a mountain behind him, realizing his teacher is on a whole other level.

5 days later, Genos decides that he wants to live with Saitama, which Saitama does not agree to, though he changes his mind when Genos offers to pay him rent. Genos then proceeds to write in his diary on his teachings. Genos then informs him that C-Class heroes will be excluded from the hero registry as they are not deemed worthy by the registry if they do not work. Saitama freaks out and decides to do heroic deeds. Genos wants to accompany him, but Genos is convinced by Saitama to aim towards the top ten ranking of the S-class, as Saitama believes that if Genos were to accompany him, he would inadvertently steal all the credit with his mere presence.

Rumored Monster Arc
While Saitama was cooking kombu, plucked from Kombu Infinity, Genos wonders why there is a pile of kombu outside, which Saitama tells him it was cheaper. Genos asks Saitama if he thought that kombu would let him regrow his hair, that it will actually not, as it was not proven as a genuine medicine, to which Genos receives an angry response from the infuriated Saitama.

Giant Meteor Arc
Saitama and Genos are relaxing and reading the newspaper. Genos states that Saitama went up in the C-Class ranking from 388 rank to 342 and that while he is still last in the S-Class ranking, in popularity he is ranked 6th, by public votes, shocking Saitama. Then, he mentions several comments about him, but is not impressed since they are all only based from one single picture of him. Even though the world does not acknowledge it, he is still astounded by Saitama, which creeps him out.

Genos receives a call to go to the Hero Association for unknown reasons. When he arrives at Z-City branch, with a suitcase, he is greeted by the third-ranked S-Class superhero Bang, who reveals that the Hero Association ordered a mass evacuation and that he and Genos are the only S-Class heroes who showed up to prevent the disaster. He explains that they were given an impossible task: a Dragon-Class Disaster is coming to Z-City in the form of a giant meteor. Genos is advised by Bang to evacuate before the meteor impacts. Genos wonders what Bang is going to do, which he replies that he decided to protect his dojo, but as he turns around to show his fighting style, Genos already left.

Genos is later shown to be leaping from rooftops, observing the panic and prepares himself for an attempt to stop the meteor. Genos activated his "Arms Mode" suitcase and throws it in the air, forming it into a pair of arms and attaches to himself, surging electricity through his body. As he decides to destroy meteor in order to protect his teacher, a large, humanoid, unmanned drone flies above him towards the point of arrival of the meteor.

Genos reveals the large robot to be another S-Class hero called Bofoi, and asks for his help in stopping the meteor. Bofoi refuses and states that he is only there to test a new weapons system. He also advises Genos to call fellow heroes by their nicknames in professional situations, and stating that his is Metal Knight. The meteor looms closer so Genos runs off to a different roof and prepares himself to attack the meteor. Before he can do anything though, Bofoi lets off a massive volley of missiles, which in the end do nothing to stop or slow down the meteor. Genos starts to prepare, but starts to doubt his abilities when Bang shows up and calms him down. Genos thinks of Saitama and comes back to his senses. He opens up his chest to reveal his power core which he attaches directly into the shoulder of his left arm. He tells Bang to get down and then launches a massive attack at the meteor. His attack does nothing to the meteor unfortunately and Genos runs out of power and collapses on the roof. Saitama shows up and destroys the meteor, causing pieces of it to rain on the city. Bang carries Genos to safety.

Genos makes a brief appearance at the end of the arc in his and Saitama's apartment, regretting his inability to stop the meteor. After a short discussion he reveals that his rank has been increased from 17 to 16, Bofoy's from 7 to 6 and that Saitama has been raised from rank 342 of the C-Class to rank 5 of the C-Class. He also explained the Disaster Level System.

Sea Monster Arc
Genos makes a appearance at the beginning of the arc in their apartment discussing Saitama's ranking after he killed a Seafolk from the other day. When he was about to explain the top B-Class hero, he gets a call that J-City is under attack and there was no competent heroes nearby to help. He and Saitama head out despite it being far away from where they are residing. On his way, he met a naked Sonic who had just escaped from the Sea King. He was the first to arrive in the Evacuation Shelter where the Sea King just took down four heroes. He put up a fight and traded blows until he was hit by the Sea King's Acid to save a girl, which ultimately disabled him. However, Saitama arrives and easily defeats the Sea King with a single punch. In the aftermath, the people were thankful but one criticized heroes for being defeated by the villains and the monster, despite their efforts. Annoyed by this, Saitama pretended to take all the credit by himself, with the purpose of giving credit to those who gave their all. Realizing this, Genos's respect towards his teacher grew more.

Alien Conquerors Arc
Genos arrives to the Hero Association meeting with Bang and Saitama; they are greeted by Atomic Samurai. He later goes to the roof of the Hero Association HQ with Child Emperor, Superalloy Darkshine, Tatsumaki, and King. There he asks Tatsumaki if he can help, only to be declined. Afterwards, Genos appears beside Child Emperor and Engine Knight and is told by Engine Knight to not trust Bofoy. Later when Bofoy's robot appears, Genos asks Bofoy what Bofoy's intentions are. Genos is relieved when he sees that Saitama is okay after the crash. However, soon Tatsumaki erupts into a fit of anger for being ignored and begins insulting Saitama. Genos retaliates by calling her a shitty brat. Unfortunately, Tatsumaki did not take that comment nicely and launches Genos at a large chunk of debris.

King Arc
Genos fought and defeated G4. Genos then went to Dr. Stench with the remains of G4 to get repairs. Genos tells Dr.Stench that he wants to become stronger. Dr. Stench replies that Genos's master has given Genos a very reckless goal and asks whether Genos can bring Saitama the next time Genos comes. Their conversation continues with the discussion of the cyborg that took Genos's hometown. Dr. Stench ask Genos whether he found any clues about the cyborg's whereabouts, which Genos replies with no. However, Genos reaffirms that he will destroy the cyborg, once he finds him. Dr. Stench reminds Genos that he is not alone and that the conflict with Mad Cyborg is their conflict and not just Genos's.

Lobster
After being called over to Bang's dojo, Saitama learns that Bang got a whole bunch of lobsters from his brother and needs someone to help him eat them. Genos complains about them being called out for something insignificant, and tells Bang to call someone else if he needs help eating leftovers, at which point Saitama tells him to stop, saying that they're only helping a lonely old man with his food problem. After Charanko arrives with the vegetables, they start preparing the hotpot while talking about a recent dojo hunter that has been attacking other dojo's. Saitama notices that there isn't any cabbage, interrupting the conversation about the dojo hunter, which annoys Charanko. After seeing Saitama look bummed about the fact that there isn't any cabbage, Genos angrily asks Charanko why he planned to make hotpot without cabbage. Saitama tries to say that it's fine, but Genos keeps arguing with Charanko because he does not feel like he even feels sorry for not having bought cabbage. After Charanko challenges Genos to a match, Bang tries to calm down the situation by saying that he will go buy the cabbage, and asks Charanko to get along with the other two.

The Blizzard Group Arc
Genos suddenly sensed something coming towards their place and went to check it out which is revealed to be Sonic who claims himself as Saitama's rival. Not wanting to disturb a busy Saitama, Genos decided to take him down on his own. They are on equal footing, with Sonic too fast for him but he, too durable from his attacks. As he tried to land a blow against Sonic, he accidentally caught Fubuki who is fighting Saitama in the way with it's impact. Saitama asked him what's going on and he replies with an apology for messing up the place. He suddenly recognized Fubuki and misinterpreted her position as a failed attempt of taking down Saitama. Fubuki was surprised that he, an S-Class Hero actually called himself a disciple of a B-Class Saitama. Sonic attacks him again, this time with exploding shurikens but was unharmed. Despite his loss in speed after this, he is durable enough to take all of Sonic's attacks and decided to increase his speed to catch up. Sonic barely evades this attack, but Genos manages to cut off his hair. This angers Sonic severely and he stops taking the fight light. Sonic uses Four Shadows Burial, thus preventing Genos from tracking Sonic. As a last resort Genos decides to try to blow up the general area. However Saitama knocks down Genos before the cyborg can do so. Saitama then brings the fight into his own hands. While watching Sonic fight Saitama, Genos admits that while Sonic is a buffoon, he must have worked hard to gain his abilities. Afterwards, Genos, Fubuki, and Saitama go to Saitama's home and listen to Fubuki discuss her ideology.

Hero Hunt Arc
Genos is briefly seen at the beginning of the arc talking to Charanko. He reveals that Garou has been put on the Hero Association's wanted list of vicious monsters and that Bang has volunteered to get rid of Garou. Genos later tells Saitama that his parts have changed and that his speed and power has been enhanced with the parts of G4. Furthermore, Genos tells Saitama that he has gained hair made of heat and shock proof fiber. Suddenly Genos comes to the conclusion that Saitama wants transplant hair as well. When Saitama comes back with a wig, Genos comes to believe that Saitama is very desperate and calls Dr. Stench to make an appointment to give Saitama a hair transplant. Saitama then explains that it is simply a disguise for the tournament and invites Genos to come to the tournament with him.

The following section contains Webcomic spoilers. You have been warned manga-only readers.

Abilities & Powers
As a S-Class hero, Genos is undoubtedly a powerful fighter. For someone his age, Genos also has significant battle experience, as he claims to have defeated countless evil entities and organizations before meeting Saitama. His youth and impulsiveness still overcome him on occasion and he remains much weaker than Saitama.

Physical Abilities
Immense Strength: Enhanced by his cyborg physiology, Genos possesses incredible physical strength, and is capable of breaking apart the ground with a drop kick, and punching rapidly with enough force to tear apart a cliff face. During his brief fight with the Sea King, he was able to land a full-force punch on the creature that sent it flying through the roof of the safety shelter.

Immense Speed: He can move so fast that he appears to be teleporting.

Immense Endurance: He can continue fighting perfectly well even with only a single arm. However, given the expression on his face after making contact with the Sea King's acid spit, it could be assumed that he feels pain from the direct acidic corrosion of his body. Although, besides this, he virtually never displays any sign of pain or fatigue.

Cyborg Modifications
Full-body Cyborg Enhancement: Genos' entire body has been replaced with combat-ready cybernetics and prostheses, giving him an extreme level of strength and speed, as well as advanced sensors and projectile attacks.


 * Core: Genos' cyborg parts are powered by an orb in his chest labeled "core," presumably designed by Dr. Kuseno. Genos has shown to be able to put his core into the shoulder of his arm, throwing all of his energy into his heat beams.


 * Armor and Replacement Parts: Genos gains not only incredible durability from his armored body, but also benefits from the nature of robotic equipment itself. Genos can lose limbs or have his body torn asunder, only to return to perfect 'health' through replacement parts and repairs (the source of the replacement parts is unclear). As an android, Genos does not seem to feel pain, and can keep fighting even when missing limbs or injured severely. Genos' durability is such that despite taking several powerful blows from Carnage Kabuto, and having one of his own powerful blasts reflected at him, he was still conscious and able to stand and walk.


 * Heat Beams: Genos' palms contain ports which allow him to fire large and powerful blasts of heat or flame significant distances. A blast from his palms was powerful enough to obliterate a multistory building which was the base of House of Evolution. Later, while sparring with Saitama, Genos reveals cannons built into his fists and arms which can produce even stronger blasts. Genos has also been shown to be able to reduce the power of his blasts to a warm breeze, which he uses to dry dishes.


 * Sensors: Genos' android body contains a number of passive and active sensors which allow him to scan the environment for enemies, both during active combat and while scouting from a distance. The sensors are not perfect however, as they can still be fooled by the extreme speed of an opponent like Saitama, and their usefulness is limited by Genos' reaction time.


 * Boosters: Once Genos' engaged, these boosters located in his shoulders enable amazing acceleration. Using his palms for jet propulsion in the opposite direction, Genos is able to perform rapid maneuvers.


 * One_Punch_Man_genos.png Anti-Saitama Tactical Arms: These are a set of replacement arms Genos used during the National Superhero Registry Arc when Genos and Saitama sparred in the quarry. These arms are differentiated from his normal arms by being black, having much larger shoulders, forearms and fists and generating a glow between the plates of metal and having his eyes go white when active. The fists and forearms of these arms open to reveal several guns. The beams generated by the guns are significantly larger that his normal blasts and are characterized by smaller individual beams circling the main beam. If he puts both of his fists together the resulting blast is massive, much larger than that of one arm.


 * One_punch_man_genos_9.png Arms Mode: A prototype weapon system that Genos possesses. When inactive it takes the form of a suitcase. To activate it, Genos pushes a button on the handle and then throws it in front of him. The suitcase splits down the middle and separates, each half then opening revealing the "arms" inside with the container then flipping back to become the attaching mechanism. Genos then throws his arms into the new "arms" and they attach to him causing quite a bit of electrical discharge. When the "arms" fully attach, parts run up his shoulders and neck and his face is framed by pieces of metal. The new arms are much thicker and are all black, with the blaster on his palm having changed shape as well. While using these arms, Genos was shown to be able to move his core to the shoulder of his right arm, directing all of his power into a massive blast.


 * Genos_g4_upgrade.jpg Upgrade: After defeating a battle robot G4 Genos replaces his parts with the parts of G4 which enhanced his speed and power. This enables him to keep up with Sonic one of the fastest characters in the series and even cut off his hair. After this upgrade the design of Genos' arms changes again.

Fighting Style
Cybernetic Combatant: Genos uses the various inbuilt weapons and mechanisms of his cyborg body to either deliver powerful attacks or to distract his opponents.


 * Incinerate (焼却, Shōkyaku): Genos launches concentrated beam to rapidly heat up a target to the point of being able to melt various metals. It was first used against Mosquito Girl.


 * Machine Gun Blow (マシンガンブロー, Mashingan Burō): Genos throws a chain of fast punches. It is strong enough to shatter a cliff face. It was first used against Carnage Kabuto.


 * Boost Attack (ブーストアタツク, Būsuto Atakku): After using his left arm for jet propulsion in the opposite direction, Genos maneuvers towards his opponent and hits them with a strong kick of his left leg. It was first used against the Sea King.


 * Rocket Punch (ロケットパンチ, Roketto Panchi): Genos' lower arm is retractable due to a cable connected to his elbow, which gives this attack a great range. Genos punches at his opponent with extreme force with the aid of boosters inside his lower arm and after the punch, his arm retracts back to its previous state. It was first used against G4.


 * Lightning Eye (来航眼, Raikōgan): (Anime-only) Genos uses his eye to produce a blinding flash of light. It was first used against the Sea King.

Hero Rating
Genos' rating determined by the Hero Association.

Anime and Manga Differences
Episode 1 Episode 2
 * Genos makes his first appearance at the end seeing dead cows sucked dry of their blood, and then walks towards Z-City following a trail of dead animals.


 * Genos is shown detecting Mosquito Girl before he engages her mosquitoes in a fight. When he was being outmatched by Mosquito Girl's improved form, Genos was launched into the air and torn apart midair. He then attempted to self-destruct midair to take down Mosquito Girl.


 * Genos' backstory is longer in the anime. Additionally, Saitama tells him to shorten it to "20 words or less" rather than "10". Genos would later remind Armored Gorilla of that exact same condition.

Episode 3
 * His fight with Carnage Kabuto is much longer as Genos attacks the head with a powerful kick then circling Carnage Kabuto shooting energy blasts at all sides, then jumps high into the air a diving straight into Carnage Kabuto to do Machine Gun Blow.


 * Shortly after Carnage Kabuto's death, Genos shows Dr. Genus that Saitama was upset about being unable to make the supermarket special sale on time and tells Saitama that they will be able to make it if they arrive in four hours.

Episode 4
 * After his fight with Carnage Kabuto, Genos is later shown getting repaired by Dr. Stench, who suggests that his next round of upgrades, the ones Genos uses in his fight with Saitama, would enable him to defeat Saitama.

Episode 5
 * In what was presumably the written portion of the hero exam, Genos was questioned on whether he was the one who destroyed the House of Evolution's building. Genos confirms this and the officials then call Sweet Mask and inform him that they are making an exception and immediately promoting Genos to S-class based on prior experience. Sweet Mask voices his approval on the matter.


 * Genos mistakes Saitama's test results as a larger S before realizing that Saitama placed into class C.


 * Genos's AS tactical arms had built in rocket boosters enabling self propelled flight at incredible speeds, this feature is omitted in the manga.


 * Additionally, when Genos and Saitama get udon, Saitama decides to challenge him to a spicy udon eating contest, which ends with Genos the victor and the two tied in competition results.


 * Sweet Mask then meets with Genos, who assumes that he had come to crush him and tells him to stop wasting his time, but Sweet Mask denies this and simply states that he met with him to welcome him to the Association.


 * Saitama and Genos part at a bridge and walk in opposite directions, initially implying that the two would walk separate paths as heroes. This is later disaffirmed when Genos simply returned to Dr. Stench to pack his belongings to move into Saitama's apartment.

Episode 7
 * Genos is seen looking up comments on the Hero Association website about Saitama destroying the meteor. Then later stopping Saitama from getting all worked up from someone calling him bald by saying they should go home. He also tells Saitama that even though the whole world would go against him, he would continue to follow Saitama.

Episode 8
 * Genos and Saitama running towards J City in the pursuit of the Sea Folk.


 * Genos getting a wave of suspicious readings on his scanner and trying to call Saitama, but doesn't get any reception.

Episode 9
 * Genos uses incinerate on the Sea King right after punching him out of the shelter making an energy beam to shoot out across the city.


 * His fight with the Sea King is much longer as goes from both outside and inside the evacuation shelter.


 * Genos developed a new technique called the Lightning Eye, using it as a a way of blinding the Sea King and bombarding him with his Machine Gun Blow.

Major Battles

 * Genos vs Mosquito Girl
 * Genos vs Armored Gorilla
 * Genos vs Carnage Kabuto
 * Genos vs Saitama
 * Genos vs Meteor
 * Genos vs Sea King
 * Genos vs Speed-o'-Sound Sonic
 * Genos vs Grizzly Nyah

Quotes

 * (To Saitama) "It all started 4 years ago... I was 15 years old and still a normal human being. Even in this harsh world I had a pretty happy and peaceful life with my family until then. But one day, a crazy cyborg attacked our town all of a sudden. He had completely lost his mind... I guess, his brain had been damaged during its transplantation into his cyborg body. He left after destroying everything in the town. The parks, the schools, the buildings, my home... Of course... my family didn't survive. Only I was miraculously spared, but as I was just a meek 15 year-old boy back then, I wouldn't have survived long all alone in the ruins of a town if Dr. Stench hadn't passed town by chance and found me. Dr. Stench is a scientist of justice and was pursuing the cyborg to stop him. I begged Dr. Stench to transform me into a cyborg and was reborn as a cyborg who fights for justice. I made a promise to Dr. Stench to find that cyborg one day and destroy him."


 * "I am willing to do anything to become more powerful. However, I can't picture myself coming even close to attaining teacher's power"


 * (Referring to Sweet Mask) "He reminds me of myself, before I met sensei. There is no mercy in his heart. A strong hatred for everything evil, eager to eliminate them all."


 * "I will eliminate you."

Trivia

 * Genos is ranked 4th in the popularity poll.


 * A running gag is that Genos' cyborg body becomes badly wrecked in every drawn-out battle he engages; indeed, the only exceptions thus far were his battles with Armored Gorilla, Charanko, and Sonic. The first being off-panel, the second ending instantly and the last one being an actual battle that had no actual winners.


 * Genos' seiyuu in the anime is Kaito Ishikawa, known for his voices of Tobio Kageyama (Haikyuu!), Shunshin You (Diamond no Ace), Kohei Izumi (World Trigger) etc.


 * ONE has said that Genos is rather powerful even amongst the S-Class heroes.