Chizome Akaguro

Stain (ステイン Sutein), known as Hero Killer (ヒーロー殺し), is a Villain that is notorious for killing many Pro Heroes.

Appearance
Stain has mow-hawk shaped hair. He wears a sleeveless shirt and dark pants and has black shoes with metal plating. He wears a long white tattered bandage around the upper half of his face which makes him look like he is wearing a mask. Around his neck he wears a long dark tattered scarf. He has knee guards, what appears to be a watch on his left wrist, and a belt around his waist.

Personality
Stain is evil and sinister. Stain appears to think lowly of Pro Heroes, as he was disgusted that they called themselves "Heroes" and even said that they are not worthy of being Heroes. However, despite this attitude towards Heroes, Stain seems to have respect for All Might, saying that he is the only one worthy of being called a Hero. Also even when being notorious for killing heroes, he still doesn't like needless bloodshed without a cause, for that reason he hates childish people like Tomura Shigaraki. Stain 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. Stain harbors hatred for the current society the world is living in, believing the current society to be overrun by fake Heroes and as a result, Stain is disillusioned.

Sports Festival Arc
Stain is introduced after heavily injuring Ingenium. In the same area as the unconscious Tensei, Stain is disgusted by the fact that Pro Heroes call themselves "Heroes", saying that they are not worthy of being Heroes. He declares that the only person who is worthy of being called a Hero is also the only one who is allowed to do him in: All Might.

Stain appears again on a rooftop, saying that the current society is distorted and twisted and declares that he will make them face reality. After Black Mist appears, Stain draws his katana and aims it at Black Mist. However, Black Mist asks Stain to withhold his blade and says that he has been wanting to meet him due to his notoriety. Black Mist asks Stain for a moment of his time, teleporting Stain and himself away.

Field Training Arc
Black Mist brings Stain to the Villain Alliance hideout to meet with Tomura Shigaraki. Stain sees that it was Tomura's Villain Alliance that raided Yuuei and that Tomura wants Stain to join his Villain Alliance. Stain asks what Tomura's goal is, to which Tomura replies that he wants to murder All Might and destroy anything that is unsatisfiable to them such as some of the students from Class 1-A. Seeing that Tomura is being childish, Stain says that Tomura is being foolish and that there is no sense in bloodshed without a cause. The mysterious voice on the monitor orders Black Mist to allow Stain and Tomura to continue talking, saying that Tomura's meeting with Stain (an experienced infamous villain) will stimulate Tomura's growth.

Stain's meeting with Tomura turns into a fight. Stain overpowers Tomura with ease and pins Tomura down onto the ground, stabbing Tomura's right shoulder with one of his daggers while pointing the other dagger at Tomura's neck. Stain also prevents Black Mist from moving. Stain tells the pinned down Tomura that in order to accomplish anything he needs a creed and a mind, telling the amateur villain that those who do not have creeds and minds will not survive and definitely die. Stain states that the current society is fake, overrun with poor Heroes and Villains who throw their power around aimlessly. Stain prepares to cut Tomura's neck with his dagger as well as the hand on his face, but Tomura grabs the dagger with his hand and begins disintegrating it. Tomura tells Stain that while he doesn't have such serious creeds, he does have a desire; which is to crush the society where All Might is set up in, wanting to plunge it into the ground. Tomura completely disintegrates Stain's dagger. Stain leaps backwards away from Tomura. Stain concludes that while their goals are different, his and Tomura's desire to destroy the current society is one thing they have in common. Stain tells Tomura that he has tested his mettle and concludes that he has a crooked creed dwelling within him and wonders what that creed will sprout. Stain declares that he might spare the Villain Alliance and won't dispose of it once he has ascertained them with his own eyes. Seeing that his business with the Villain Alliance is over, Stain demands to be returned to Hosu as he has unfinished business there.

Black Mist warps himself, Stain and Tomura to Hosu. Tomura notes that Hosu is quite prosperous while Stain says his goal is to reform Hosu by sacrificing the "fake" Pro Heroes that work there. Stain states his belief; that the title of Hero should only be bestowed onto people who achieve great undertakings, saying that there are too many "fake" Heroes that only work for money. Stain leaves to finish his business, saying that he will keep appearing until society realizes its error and jumps off the building.

Stain goes to an alley and find a Pro Hero, defeats the Pro Hero with ease and immobilizes the Pro Hero's movements. Stain hears the chaos in Hosu and realizes that Tomura has made his move. Stain decides to leave Tomura to his own mechanisms while he finishes his business. Stain prepares to kill the Pro Hero with his katana. However, Stain feels the presence of someone approaching him from behind and uses his katana to slash at the person, knocking the person down to the ground as well as knocking off the person's helmet and glasses (which is revealed to be Tenya). Stain sees that the person who tried to attack him is a child, telling the child to leave. Tenya gets up, telling Stain that he has been searching for him and looks at the Hero Killer with vengeful eyes. Stain points his katana at Tenya and says that he has avenging eyes, telling Tenya that if the situation demands it children will also be targets. Stain prepares to go and finish his job of killing the Pro Hero, however, the enraged Tenya yells to Stain that he is the brother of a Pro Hero he cut down and he has come to stop Stain in his stead. Tenya tells Stain to never forget his Hero name; Ingenium, which is the name of the Hero that will take him down. Seeing that Tenya is serious about being a Hero, Stain tells Tenya to prepare to die.

Powers and Abilities
Stain 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 other to the point of being unable to make a full recovery.

Quirk
Stain's Quirk is unknown. However, it is insinuated that Stain's Quirk prevents people from moving, since Black Mist could not move at all even when he wanted to help Tomura.

Equipment and Weapons

 * Katana
 * Five Daggers

All Might
Though Stain's end goal is to kill him, he seems to have a great deal of respect for All Might and even states that he is the only true hero in the world.