Episode 29

"Hero Killer: Stain vs. U.A. Students" is the twenty-ninth episode of the My Hero Academia anime and the sixteenth episode of the second season.

Summary
In the aftermath of a sudden attack from a Nomu look-alike, Izuku exists the train and searches Hosu City for Gran Torino. He ponders whether this Nomu is related to the other, and uses his newly mastered abilities to navigate the city. Meanwhile, the aforementioned retired hero battles with Nomu. He's able to evade most of it's attacks, claiming that it's movements aren't anything special.

The Nomu decides to indiscriminately attack nearby civilians. Gran Torino goes to stop him, but then Nomu is suddenly engulfed in flames. Endeavor appears, having been the one to scorch the creature. He tells the elderly hero that he will handle Nomu. When the civilians question Endeavor's appearance, he replies that he is there because he is a hero.

Izuku eventually happens upon an ensuing battle between pro heroes and other Nomu's after hearing Manual cry out Tenya's name. Tenya is absent from the scene, and Izuku realizes that he must have went off in search of Hero Killer: Stain. A pro hero warns Izuku to move away from the battle and so he leaves to search for his friend. Watching from a nearby building, Tomura praises the Nomu's for the chaos they have created. His master loaned him the Nomu's so that he could kill Stain, only because Tomura doesn't like him. Kurogiri asks if Tomura will join, but Tomura replies that he won't due to his injury.

Concurrently, the hero killer tries to strike Tenya down, but is met with a high speed kick as a counter. Stain avoids it and kicks Tenya to the ground while stating he allowed Ingenium to live so that news of his own exploits would spread. Then he pins Tenya down and stabs him in the shoulder, claiming Tenya is weak just like Ingenium because they are false heroes. The vengeful brother rebukes Stain's claim and defends his brother's honor, saying that Tensei was a splendid hero. Tenya promises to kill Stain to avenge his brother but is shocked when Stain responds by telling him to save the injured pro hero, Native, first.

Stain licks the blood from his blade, and suddenly Tenya is unable to move his body. Stain preaches that Tenya must act selflessly by rescuing others first, not selfishly brandishing his powers. Stain goes on to say that seeking revenge just to satisfy one's selfish desires is the furthest thing from what a hero should be, and thats why Tenya will die as an offering to a more just world. Tenya refuses Stain's words because he is the criminal who hurt his brother.

During Izuku's search for Iida, he surmises that the League of Villain's and Stain must be connected somehow. Most of Stain's attacks on heroes have been in unpopulated areas. Using that information, Izuku decides to search all the alleyways close to Manual's Hero Office and eventually finds Stain just as he's about to finish Tenya.

Izuku acts swiftly, using One For All's power to deliver a powerful smash to save his friend. He tells Tenya they need to move to a more open area so pro heroes can support them, but the former reveals he's unable to move ever since Stain cut him. Izuku surmises that perhaps Stain's Quirk activates by cutting his opponents, and then realizes that Native has been injured as well. Unable to carry both of them away, Izuku bravely decides to protect them both by holding off the hero killer on his own.

Stain warns Izuku that it's his duty to kill Tenya, and if the young man gets in his way that the weaker of the two powers will be culled. Intimidated, Izuku realizes that Stain is a totally different breed of villain than those at the U.S.J. and decides to send out his location information. Tenya pleads for Izuku not to get involved because it has nothing to do with him but he refuses, re-stating words he had once heard from All Might: That the essence of being a hero is meddling where they don't have to. Stain takes notice of Izuku's words and recognizes him from the photo Tomura showed him earlier.

Their duel begins as Izuku uses One For All: Full Cowl to swiftly close the distance between him and Stain, effectively negating the advantage of the former's longer reach. The hero killer tries to slash Izuku with a knife using his free hand, but the young hero slides through his legs. Stain moves to counter by swiping his Katana behind him, but Izuku promptly evades by jumping above Stain. Then, Izuku uses a 5% Detroit Smash and delivers a powerful blow to his opponents head. Surprised by Izuku's feat, Tenya compares his movement's to Katsuki's. Unphased by Izuku's attack, Stain licks the blood from his knife and immobilizes him. Izuku realizes that Stain managed to graze him, and that blood is the key to attactivating his Quirk. Stain is impressed with Izuku's skill and conviction, and decides that Izuku is worth allowing to live because he is different from Tenya and Native. The hero killer prepares to take the lives of his next two victims, but is abruptly forced back when a stream of fire comes at him.

Shoto appears suddenly, scolding Izuku for not explaining the urgency of the situation because he could have gotten there sooner. He explains that it took him a while to decode Izuku's message since he only sent his location. He sends a wave of ice at Stain to repel the villain while securing his injured allies. Shoto also notes that he realized Izuku must have needed help and not to worry because pro heroes are on the way. As he continues to push Stain back using both his ice and fire, Shoto warns the hero killer that he will not allow him to kill his friends.

Izuku warns Shoto not to allow Stain to ingest his blood and Shoto decides to keep his distance. However, Stain quickly throws a knife at Shoto, who narrowly evades it and has his cheek cut open. Stain rushes Shoto and is blocked by a pillar of ice, howbeit he tossed his katana in the air at the same time to distract his foe. Abstracted, Shoto nearly allows Stain to lick the blood from his face but repels him using fire. Shoto counter attacks with waves of ice, but Stain grabs his katana to defend himself and commends Shoto for his strength.

Tenya pleads for Shoto to stop because he's inherited Ingenium's name, and only he should stop the hero killer. Withal, Shoto replies that Ingenium never had the look of vengeance plastered on his face. He creates a giant wall of ice, but Stain slashes through it and tells Shoto that it's foolish to block his own view when his opponent is father then him. Then Stain stabs Shoto's left with two throwing knives and moves above him. Just as he's about to stab Shoto from above, Izuku unexpectedly grabs him and tackles him away. Shoto guesses that Stain's Quirk may have a time limit, but Native explains that Izuku was the last to suffer from it, so that cannot be the case. Izuku comes to the conclusion that Stain's power's effectiveness varies depending on blood type, to which the hero killer confirms.

Izuku resolves to distract Stain while Shoto supports him from behind since the former has already shed so much blood. Although reluctant to the risk, Shoto agrees to protect Tenya and Native together with Izuku. He recalls worrying about Tenya ever since Ingenium was attacked because he recognizes someone who's acting on pent-up resentment. Shoto also knows too well how that negativity can cloud someone's judgment.

Shoto recollects visiting his mother, and how visiting her cleared up his own perception. He told her everything that happened and so she apologized and forgave Shoto for not visiting her for a long time. She also encourages him to move forward in his life without anything holding him back, as that would be her salvation. That's why he decided to intern with Endeavor's agency, not because he has forgiven his father, but because he wishes to learn from the experience of the number two hero. Shoto realizes that everything could have been simpler for him, but never noticed until Izuku opened his eyes with just a few words.

With the intensity increasing, Stain heightens his strength and overpowers Izuku. He cuts open his leg and licks the blood to paralyze him. Shoto supports him, but Tenya again pleads for them to stop. Shoto rejects his plea, tells Tenya to stand up and look properly at who he wants to become. Stain slashes through a wall of ice and goes to attack Shoto, who responds by releasing his fire. After Shoto tries to save Tenya like Izuku had done for him, Tenya reflects shamefully on himself and starts to move his hand.