"Both this sham-filled society... and the criminals who wield their power in the name of petty mischief... are targets of my purge... All for the sake of a better society... "
Chizome Akaguro (赤黒血染 Akaguro Chizome?), best known by his villain name Hero Killer: Stain (ヒーロー
Chizome is an intimidating, muscular man who walks with a distinct hunch. He has black hair and wears it in a messy fashion that would drape over his face if not for his headband and mask. Chizome's face is mostly flat because he doesn't appear to have a nose, and he has blood red eyes. His unique tongue is unusually long and tainted with many small bumps.
The Hero Killer sports a dark colored sleeveless combat suit, plated with metal armor across his body to holster his weapons. The torso is sleeveless, Chizome instead wraps his arms in bandages.
He also wears long black wristbands, and a watch on his left wrist. His knees are protected with metal pads and the costume is completed with black, steel boots. Chizome always dons his signature blood red scarf and matching headband. As well as the tattered cloth he wears round his face as a mask.
Chizome is a cold, unforgiving man with a sense of duty to cleanse society of false heroes. He believes that those who work as Heroes to collect income are unworthy of being called the name and only All Might is a true hero. Due to his strong ideology, Chizome took it upon himself to become the Hero Killer: Stain to stain his own hands with blood to purge fake heroes and change the current society.
Chizome does not wish to kill those who are not targets for his own cause. He dislikes needless bloodshed and came to blows with Tomura Shigaraki because of it. He was reluctant to attack Tenya Iida before the hero in training provoked him. He even told Tenya the true traits of a hero in contrast of those who desire to use their Quirks in selfish ways. Chizome spared Izuku Midoriya because he showed characteristics of a true hero. He believes heavily in creeds and convictions, stating that they are needed in order to accomplish anything and that without them people are weak and will eventually die.
In spite of his extremist views and beliefs, Chizome does have genuine ideals about Heroism which he stands by firmly. He does not hesitate to save people he deems worthy of being called Heroes, does not like killing without reason, and will even give advice to his enemies. He seems to acknowledge that what he is doing is morally wrong, but believes that in order for society to be put on the right path, someone must be what he is, indicating he sees himself as somewhat of a martyr.
The Hero Killer's conviction gives him an incredibly murderous aura and bloodlust that paralyzed several heroes in fear. It gives him enough confidence to willingly challenge several pro heroes at once, even after sustaining major injuries.
All Might's debut as a Hero deeply inspired Chizome. Since then, Chizome aimed to become a Hero like All Might. Chizome entered a private Hero course high school to train to become a Hero. However, Chizome became hopeless and despaired after seeing the school's "fundamental decay"; that the students there were becoming Heroes for the money and personal gain. Disillusioned by the reality of Heroics, Chizome dropped out during the summer of his freshman year.
After dropping out of high school, the teenage Chizome preached an ideology which he called the "Revival of Heroics" through street oratory speeches and soapbox speeches. However, no one listened to him.
Over the following decade, Chizome realized that only action will create his ideal world and change Heroics for the better. Chizome researched and disciplined himself in the training of the killing arts through self-study. He did this in order to achieve his duty of "Revival of Heroics". During this decade, Chizome's parents died (it is unknown what led to their deaths but it is believed that Chizome was not involved).
After completing his training in the killing arts, Chizome had a brief stint as a vigilante, going by the name of Stendhal, hunting villains to make up for the heroes mistakes. During this time he had worked with the Vigilantes, such as Knuckleduster, The Crawler, and Pop Step. During this time he had became more and more disillusioned with hero society to the point where he began to work with a villain who was supplying the quirk enhancing drug Trigger to several small time criminals.
Sometime later, after his face got disfigured, he took up the mantle of Hero Killer Stain and begun advocating the "Revival of Heroics". In this ideology of "Revival of Heroics", Chizome (now known as Stain) stated the guidelines of being a Hero: that Heroes must not desire rewards or compensation, and that people can only have the title of Hero when they commit the ultimate acts of self-sacrifice. The ideology stated that the "Heroes" of the modern world are fakes who pretend to be Heroes.
Stain then began implementing his "Revival of Heroics" by killing Pro Heroes, deciding that he would not stop his purge of the Pro Heroes until the world realized the flaw in the Heroics system. Stain's end goal with implementing his ideology "Revival of Heroics" was to create a just world filled with true Heroes.
Chizome is first introduced after having already killed seventeen heroes and injured twenty three beyond recovery. The Hero Killer's actions lead him to Hosu City where he is confronted by Ingenium. Chizome heavily injures the pro hero and leaves him for dead after monologuing about his disgust over those he believes are not worthy of being called heroes. He believes the only person who is allowed to do him in is All Might, and that only he is a true hero. 
Chizome moves to a rooftop to scout potential targets, but he is suddenly confronted by Kurogiri. He threatens the villain with his Katana and Kurogiri asks him to hold his blade. He proposes a meeting between the League of Villains and the notorious Hero Killer: Stain and then teleports them away.
Kurogiri brings Chizome to the League of Villains' hideout to meet with Tomura Shigaraki. He insists that Tomura allow Stain to join their party. Chizome questions the goals of the league of villains and Tomura replies that he desires to kill All Might and anything he doesn't like, including a particular U.A. student. Unimpressed by Tomura's childish nature, Chizome threatens them both because he believes Tomura is the worst kind of person and that there is no sense in bloodshed without a cause. 
Chizome immobilizes Kurogiri and pins down Tomura while cutting into his shoulder with a knife and holding another to his neck. He preaches to his overpowered foe that he will remain a weakling who will achieve nothing with real convictions or desires. He goes on to state that the world is overrun by fake heroes and villain who flaunt their power around chasing petty dream and they must all be purged.
As Chizome's knife draws closer to the Tomura's face, the villain reacts by quickly grabbing the knife and disintegrating it with his Quirk. Chizome retreats a short distance and Tomura responds to his ideology. Tomura reveals that he is driven by the desire to kill All Might and destroy the people who worship him. Although Chizome thinks that their goals oppose one another, he agrees that they both want to destroy the present. Tomura demands Chizome leaves, but Chizome reveals that he threatened him to test his motives because people show their true selves while on the verge of death. He says he will allow Tomura to grow and demands to be returned to Hosu City.
Kurogiri warps himself, Chizome and Tomura to Hosu. Tomura asks what Stain plans to do there, to which he replies he will reform Hosu. He plans to do so by killing the false heroes who's only desires are money, when heroes should be those who achieve great deeds. He leaps off the rooftop, stating that he will continue to appear until society realizes its error. In the seven places that he has appeared so far, Chizome has attacked at least four pro heroes. He has only attacked Ingenium in Hosu and decides to attack the pro hero Native next. After paralyzing Native, Chizome notices the chaos ensuing in the city and connects it with the League of Villains. He says he will deal with them after Native, but is then interrupted by Tenya Iida. Tenya tries to attack Chizome, but he notices the young man first and knocks him down. He demands the child leave, but Tenya declares that he will stop the Hero Killer in the place of Ingenium. Due to Tenya's selfish and vengeful desires, Chizome decides to take it upon himself to purge him from the world. 
Tenya attacks with a high speed kick, but the Hero Killer evades and pierces Tenya's arm with his spiked boot. Then he kicks Tenya to the ground and says both Ingenium and his brother are weaklings. He reveals he allowed Ingenium to live to spread the word of the Hero Killer's exploits. Chizome claims that neither of them have the right to be called a hero. Tenya refutes this and threatens to kill Stain for his brother. Chizome responds by telling Tenya that he should be focused on helping Native and that his lust for vengeance is blinding him and becoming the furthest thing from what a hero should be. Just as the Hero Killer prepares to claim another victim and sacrifice Tenya for a more just world, Izuku Midoriya leaps in out of nowhere and punches Chizome back.
Izuku found Chizome by going by what he had heard on the news. He knew that Stain attacked all his victims in low populated areas and searched all the back alleys by Manual's office until he found them. Chizome commends Izuku for saving his friend, but warns him that if they clash the weaker of them will be culled.
Izuku decides to stand up to Stain as a hero, impressing the Hero Killer with his strong conviction. Their bout starts and Stain is further roused when Izuku closes the distance between them to negate his opponent's longer reach. Chizome strikes Izuku with another blade but the young man narrowly evades by moving through Chizome's legs. Chizome adjusts by slashing behind him, but Izukus swiftly moves into the air above him and strikes Chizome with a 5% Detroit Smash attack.
The Hero Killer is barely rocked by Izuku's smash and manages to lick a trace of Izuku's blood from his knife. Chizome claims he saw through Izuku's plan, but praises the young man and says he is worth allowing to live. He decides to try and kill Tenya instead, but is once again interfered with when another U.A. student arrives to save his friends. Shoto Todoroki nearly blasts Stain with a stream of fire, forcing him to dodge. He continues to attack with ice and fire to continue forcing the Hero Killer away and declares that the villain won't kill anyone tonight. Chizome grazes Shoto's cheek with a throwing knife and rushes him while uses his sword as a distraction to get in close and lick the blood from his face. Shoto uses his fire to keep Stain away, garnering the villain's praise, and the pair battle it out. Chizome consistently evades Shoto's attacks of fire and ice and manages to pierce his arm by throwing two knives into it. Stain plans to use the opening to kill Native, but Izuku is freed from paralysis and throws the villain away.
Izuku and his allies deduce Chizome's Quirk gives him the ability to immobilize people by ingesting their blood, and it's time limit is based on blood type. Izuku and Shoto decide to protect Native and Tenya together, and Chizome comments that the commencing fight will be difficult. He and Izuku battle in close quarters while Shoto supports him from a distance with his Quirk. Stain eventually cuts Izuku's leg and paralyzes him before attacking Shoto again.Shoto counters by shooting flames at Stain, but he evades and claims that Shoto fights too recklessly because of his powerful Quirk. He nearly cuts the student down, but Tenya comes to the aid of his friend after being freed from Bloodcurdle's effects. He uses his Recipro Burst technique to save Shoto by kicking Chizome's sword in half and then repeling the villain with a subsequent kick.
Tenya apologizes to his allies for their injuries, but Chizome refutes Tenya's reformation and calls him a cancer to society that must be killed off. Stain becomes flustered and acts gets more ferocious in his attempts to kill Tenya and Native. Shoto keeps him at bay with his elemental attacks and Chizome tries to get him out of the way with a throwing knife. Tenya throws himself in front of it and it pierices his arm. Chizome follows up by pinning Tenya down with a second dagger and dives down at the pair of young heroes in training.
He doesn't notice Izuku's time limit is up and the latter rushes him with his power. Tenya does the same, using Recipro Extend to clash with Stain. They both attack the villain at the same time, with a Quirk enhanced punch and kick respectively. Chizome makes one last ditch effort to kill Tenya, but he evades and kicks Stain into the air. Shoto uses the opening to burn Chizome with a blast of fire. These additional blows cause Stain to fall unconscious and lay ontop of a pillar of Shoto's ice. The students take his weapons and tie Chizome up to restrain him..
Izuku, Shoto, Tenya, and Native leave the alley with the unconscious Hero in tow. They are met by several pro heroes when a winged Nomu swoops down and grabs the injured Izuku before flying away. The Nomu was injured by Endeavor and it's blood gets on the cheek of one of the pros. Chizome wakes up and licks it off to paralyze the beast before freeing himself and leaping into the air to stab the Nomu's brain and save Izuku. Despite being heavily injured, Stain kills the Nomu andstates that the "fake" Pro Heroes and the pathetic criminals in society are his targets for his purge to create a stronger society.
Chizome notices Endeavor's arrival and decides to cofront the "false hero" despite being outnumbered. His mask falls off and he shouts his convictions to his opposition. He tells them that the streets must run with the blood of hypocrites, that he will reclaim the word "hero" and goes on to challenge the fakes to stop him. All while slowly stepping towards the group of heroes who are frozen with fear by the Hero Killer's bloodlust. Stain's malefic aura sends chills down their spines as he shouts that only All Might is worthy enough to stop him. He only stops when his lungs are perforated by a broken lung and he loses consciousness. Although unconscious, Chizome was the only one present at the scene with enough fight left in him to stand against his enemy. 
The next day, the Chief of Hosu Police states that Stain sustained several burns, bone fractures, perforated lungs, and other serious injuries but he is still alive and is undergoing treatment for his grievous injuries.The news of Stain's defeat and arrest spreads like wildfire throughout Japan. Chizome's true name and backstory are revealed in published articles and becomes a major topic.His ideology inspires villains to rally and unite themselves under the League of Villains.
After undergoing treatment for his injuries, Stain was incarcerated in Tartarus, a special prison for criminals for whom the death penalty is not enough.
Quirk and Abilities
Bloodcurdle (凝血 Gyōketsu?): Stain can paralyze and immobilize an opponent by ingesting samples of their blood. The amount of time a victim is paralyzed for varies depending on blood type, with B having the longest duration, then in decreasing order, AB, A, and O. Regardless, the maximum amount of time anyone can be paralyzed is 8 minutes. As noted below, his speed and endurance are also both superhuman grade, which is how he manages to get access to his opponents' blood in the first place.
Overall Abilities: Stain is a powerful villain, as he was able to battle and heavily injure Ingenium, a popular and powerful Pro Hero, without much difficulty, leaving him in a critical state. Stain also was able to murder 17 known Pro Heroes and crippled 23 others to the point of being unable to make a full recovery. Even Shoto Todoroki commented that Stain is a strong combatant. It took the combined efforts of Izuku, Shoto, and Tenya to take down Stain, but even using all their power only managed to briefly knock him out; Izuku commented that Stain was probably holding back against them and could have killed them any time, to which Shoto agreed. He can emit an overwhelming amount of blood lust when provoked, enough to even cause Endeavor, a highly regarded hero, to back up.
Enhanced Speed & Reflexes: Stain has proven himself to be quite agile as he was capable of dodging Tenya's high-speed kick with ease and has shown to have great speed as well as reaction time.
Immense Endurance: Stain also appears to have a high pain threshold, as he barely felt any pain when Izuku dealt his 5% Detroit Smash to his head but was completely unfazed. Stain has immense endurance as his lungs were perforated by his broken ribs and, despite losing consciousness due to his injured lungs, still stood standing even though he was unconscious.
Highly Perceptive Combatant: Stain has shown creativity and mastery over his fighting style having been able to deal with close and long range opponents through a mix of misdirection, aggression, prediction and use of the environment he is given in order to get up close to his target or at the very least draw even the slightest amount of blood to activate his Quirk.
Weapon Arsenal: Before being arrested, Stain carried various weapons with him, which included a katana, five daggers, throwing knives, toe-spiked boots and folding knives. He was apparently skilled in using them.
Stain seems to have a great deal of respect for All Might and even states that he is the only true hero in the world. His respect towards him came from his respect he had towards him when he was a teen, All Might was the reason Stain decided to become a Hero. Stain's respect and admiration for All Might runs so deep that before finally falling unconscious, Stain declared that only All Might is allowed to defeat him.
Stain despises Tenya for his desire for revenge against him. He scolded the young hero over his selfish desires of revenge over saving the Pro Hero he was about to kill. Even after Tenya learned from his mistakes Stain stopped at nothing to kill him, claiming that people don't change their views easily. Tenya however, though he hates him immensely for almost killing his brother, acknowledges Stain was right about him and resolved to start over as a Hero.
Stain views Shigaraki as an immature child who wants to cause needless bloodshed all for nothing. He did not hesitate to pin him down when they conversed and refused to join his alliance, which earned him Shigaraki's hatred. Shigaraki also despised how Stain's capture was the main news story insted of the Nomu attack.
Stain, like All Might, respects Izuku for his convictions and bravery he displayed in his fight with him. He acknowledges Izuku as a true hero. Because of his respect, he both spared Izuku when he first fought him and risked his life to save the young hero in training from a Noumu.
Stain seems to also respect Shoto for his skills and convictions as a true hero. Shoto, however, despises Stain for his ideologies about "fake" Pro Heroes.
- Stain's design, having no nose, bandanna and samurai equipment is possibly inspired by the Teenage Mutant Ninja Turtles in their early, dark comic debut.
- His weapons, dark outfit, and violent ideology could also be a reference to the general trope of the violent antihero's of the 90's
- Additionally, Stain's personality is very similar to the Marvel anti-hero, The Punisher. Both are former heroes who turned to darker methods of obtaining their forms of "justice". They both also have a strong moral code separating them from true villainy (Punisher only murders criminals while Stain only murders corrupt heroes).
- Stain's blood type is B.
- A character named Stendhal in a spinoff has seemingly the same abilities of Stain.
- Stain's name contains the kanji for red (赤?), black (黒?), blood (血?), and stain (染?).
- The two middle kanji for can be combined to form the word venous blood (黒血?)
- (To Tomura Shigaraki) "To truly accomplish anything... one needs will and conviction. Those without it... the weak ones.. They'll be weeded out. It's only natural. That's why you're about to die."
- (To Kurogiri) "Hero is a title reserved for those who perform truly great feats! Too many are undeserving... Just money worshipers playing hero! Until this society wakes up and rectifies itself... I will continue to do my work."
- (To Tenya Iida) "Forget about yourself for a second and try saving others. Don't wield your power for your own sake. Because getting trapped by your own hate and acting out of pure self-interest... makes you the furthest thing from a hero."
- (To himself) "Both this sham-filled society... and the criminals who wield their power in the name of petty mischief... are targets of my purge... All for the sake of a better society..."
- (To various heroes and U.A. students) "If I don't fix it... if someone isn't... stained with blood...! If heroes aren't restored...!! Come! Just try me... you fakes! The only one allowed to kill me is... All Might, a true hero!!"
|Independent||Stain • Giant Villain • Toxic Chainsaw • Trapezius Head Gear • Sludge Villain|
|Original Members||All For One • Artificial Humans • Kurogiri • Tomura Shigaraki|
|Recruits||Dabi • Himiko Toga • Magne • Moonfish • Mr. Compress • Muscular • Mustard • Nomu • Spinner • Twice|
|Prominent Members||Overhaul • Chronostasis • Mimic|
|Eight Expendables||??? • ??? • Setsuno • Hojo • Tabe • ??? • Rappa • Tengai|
|Members||Curator • Zookeeper • Bearhead|