My Hero Academia Wiki
My Hero Academia Wiki

The Unforeseen Simulation Joint Arc (ウソの災害 (さいがい) 事故 (じこ) ルーム (へん) Uso no Saigai Ya Jiko Rūmu Hen?) is the fourth story arc in My Hero Academia and the fourth story arc in the U.A. Beginnings Saga.

Having completed the Battle Trial, the students now take a trip to the Unforeseen Simulation Joint Facility to train their rescue skills. However, villains unexpectedly show up and now the students must survive their first fight against actual villains.


Electing a Class President

Izuku and Momo are elected class representatives.

With the news that All Might has joined U.A. High School faculty, the press has been trying to get a scoop on All Might by going to U.A. and asking students and teachers about him, but their attempts fail due to the infamous "U.A. Barrier" (a high tech security gate) keeping them out. In Class 1-A, Shota Aizawa announces that their class needs to pick a class President. After making a vote, Izuku is elected as the Class President and Momo becomes the Vice President.

Izuku, Ochaco, and Tenya sit together and have lunch in the mess hall. Izuku is unsure about being class President but Tenya asserts that he will be alright. After Ochaco notes Tenya's formal attitude, Tenya goes on to explain his history; that he comes from the prestigious Iida Family, a family that has been in Heroics for generations. Tenya goes on to say that he aspires to be like his big brother, Tensei Ida, who is a famous Hero in his family. Suddenly, U.A.'s siren goes off, indicating that someone had infiltrated the school. The students in the lunch hall evacuate in a disorganized and rushed manner.

Tenya Ida: President of Class 1-A

Tenya alerts the students about the false alarm.

Tenya sees that the mass media is outside and realizes that the siren was not indicating an intrusion. Looking for a way to calm the crowd, Tenya asks Ochaco to make him float and he jumps into the air. While in the air, Tenya boosts himself onto the emergency exit board. Tenya yells out to the evacuating students to calm down and says that it is just the press, causing the students to stop their panicking and thus stopping the chaotic evacuation.

Back in Class 1-A, Izuku makes an announcement; that he is resigning as class President and declares Tenya to be his successor, saying that Tenya is the right choice after seeing his actions in the lunch hall. Thus, Tenya officially becomes the class president of 1-A.

Meanwhile, the U.A. faculty see that most of the U.A. Barrier has disintegrated, indicating that someone did indeed infiltrate U.A. They wonder if an ordinary reporter could have infiltrated the academy. However, Mr. Principal denies that possibility, saying that an element of evil instigated the infiltration and he wonders if the infiltration was intended to be a declaration of war.[1]

Trial of Rescue: Class 1-A's Excursion to the USJ

Mt. Lady overwhelmed by Habit Headgear.

At 7:55 in the morning on Wednesday, the pro heroes Kamui Woods and Mt. Lady are fighting a villain called Habit Headgear who has taken an innocent family hostage. The battle does not fare well for neither Kamui or Mt. Lady as Habit proves to be quite strong. Suddenly, All Might rushes through and uses Missouri Smash against Habit, defeating him in an instant and saving the family in the process. Kamui and Mt. Lady thank All Might for his assistance. All Might then quickly leaves as he has to go to U.A.

At 12:50 in the afternoon, Shota announces that their lesson in Foundational Skill of Heroics will be the Trial of Rescue. The lesson will take place at the Unforeseen Simulation Joint (USJ) Facility, a practical training area that is designed to simulate any kind of accident or disaster. One of the teachers for the lesson, Space Hero Thirteen (a pro-hero who helps out with disaster relief) gives a speech to Class 1-A, telling them that their lesson will be about wielding their Quirks for the sake of human life.

An Unexpected Visit: The League of Villains Attacks

Tomura and his league warping into the U.S.J.

After the speech is finished, Shota sees a black portal opening up and dozens of villains come through it. Shota confirms the situation is real and orders his students to huddle together and commands Thirteen to protect the students, gearing up for battle himself. One of the villains says that All Might was supposed to be here according to the curriculum they procured yesterday, which causes Shota to realize that they were the ones who infiltrated the U.A barrier. Another villain is shown to be disappointed that All Might is not here and wonders if All Might will show up if they kill the children.[2]

Shota takes charge and orders Thirteen to evacuate Class 1-A and try alerting the rest of the school. Shota goes to fight the villains who realize who he is as he defeats many of them quite easily due to his expertise in one-on-group battles.[3]

Shota surrounded by villains.

Meanwhile, Thirteen and Class 1-A attempt to evacuate, but Kurogiri, a high-ranking villain, stops them, telling the students and Thirteen that they are the League of Villains and that their goal is to kill All Might. Katsuki Bakugo and Eijiro Kirishima attack Kurogiri but fail to do any damage. Kurogiri uses his Quirk to teleport most of the Class 1-A students to different areas of the USJ.

Izuku is teleported to the Flood Zone area of the USJ where one of the villains immediately tries to devour him. However, Tsuyu attacks the villain and uses her tongue to grab Izuku and throw him onto a ship. She also throws Minoru Mineta onto the ship as well and then climbs onto the ship herself. After thanking Tsuyu for saving him, Izuku wonders why the villains want to kill All Might. Seeing as how thinking will not help, Izuku declares to Tsuyu and Minoru that their only choice now is to fight and win, much to Minoru's shock.[4]

Class 1-A vs. the League of Villains

In Recovery Girl's Nurse's Office, All Might tries to contact Thirteen and Shota but is unable to. All Might decides to go to the USJ in a few minutes. However, Mr. Principal arrives and tells All Might to relax. Mr. Principal starts to talk about educational theories with All Might noting that he has not changed one bit.

Meanwhile, at the USJ, Thirteen notes that they cannot make contact with the outside world at all. Thirteen orders the Class President Tenya to dash to U.A. to tell the teachers there what is transpiring and get them to come and help. Tenya is skeptical, thinking that running back to U.A. while leaving behind his classmates would be cowardly and disgraceful. After some encouragement from his classmates and Thirteen telling him to use his Quirk to save others, Tenya decides to dash back to U.A. Kurogiri overhears their plans and goes to stop Tenya, but Thirteen stands in Kurogiri's way. Kurogiri and Thirteen prepare to battle each other.

Izuku, Tsuyu, and Minoru escape the Flood Zone.

At the Flood Zone, a shocked Minoru criticizes Izuku's plan to fight and win, but Izuku ignores him and begins strategizing. Izuku concludes that the League of Villains does not have information on their Quirks and while the League of Villains beats them in experience and numbers, they have the element of surprise on their side. Tsuyu and Minoru reveal the powers of their Quirks and Izuku uses this knowledge to plan a strategy.

After one of the villains strikes the ship, it begins to break apart. Izuku jumps off the ship and puts his strategy to work, using Delaware Smash on the surface of the water, causing the water to spread out. Tsuyu then grabs Izuku with her tongue and Minoru throws his sticky substance into the spread-out water. The spread-out water converges in the center along with Minoru's sticky substance (with the villains being pulled in), causing all the villains in the water to be stuck together by Minoru's Quirk. With the villains stuck together, unable to do anything and thus defeated, the three students make their escape, with Tsuyu saying that they were impressive.[5]

Izuku, Minoru, and Tsuyu successfully escape the Flood Zone. Tsuyu wonders what their next course of action should be with Izuku suggesting that they should try and call for help. Tsuyu then notes that their teacher Shota is fighting a large group of villains in the Central Plaza. Izuku then says that they should watch their teacher battling and when there are openings, they should jump in and help to relieve their teacher's burden.

At the Landslide Zone, Shoto Todoroki easily defeats the villains by freezing them all.

Momo, Kyoka and Denki fight villains at the Mountain Zone.

At the Mountain Zone, Denki Kaminari, Momo Yaoyorozu, and Kyoka Jiro battle the villains there. Momo creates an insulator sheet to protect herself and Kyoka, allowing Denki to discharge a great amount of electricity, which electrocutes all the villains, defeating them.

Shota faces Tomura.

At the Central Plaza, Shota continues fighting the villains and finally faces the ringleader, Tomura Shigaraki. Shota manages to strike Tomura, but Tomura grabs Shota's elbow and starts disintegrating it. Shota punches Tomura and knocks him down, then defeats another two villains who attempted to attack him. Suddenly, a monstrous villain appears behind Shota.

Near the exit of the USJ, Kurogiri and Thirteen battle. However, Kurogiri defeats Thirteen by warping Thirteen's Quirk against the hero, incapacitating the hero. Tenya begins running towards the exit with Kurogiri in pursuit. As Kurogiri appears before Tenya, Mezo Shoji jumps into Kurogiri, stopping him and allowing Tenya to continue running towards the exit.

Izuku, Tsuyu, and Minoru reach the Central Plaza but are shocked to see that their teacher Shota is severely wounded and on the ground due to being defeated by the monstrous villain. Tomura asks the heroes to tell All Might that he is wanted by Artificial Human "Nomu".[6]

Katsuki and Eijiro battle the villains in the Ruins Zone.

At the Ruins Zone, Katsuki and Eijiro defeat the villains that are there with Katsuki calling them weak. Eijiro suggests that they should go help their classmates, with Katsuki declining his plan and instead of wanting to beat Kurogiri, saying that he is the League of Villains' gateway and defeating him will put the League of Villains at a disadvantage. One of the surviving villains tries to attack Katsuki from behind, but Katsuki knocks out the villain with an explosion.

Tenya trying to out speed Kurogiri.

Near the exit of the USJ, Tenya is about to reach the exit, but Kurogiri once again impedes his path. As Kurogiri is about to cause Tenya to warp away, Ochaco grabs onto Kurogiri's plates around his neck (after surmising that those plates are part of his real body) and uses her Quirk to make the plates float, causing Kurogiri to go into the air. Tenya reaches the exit, goes through it, and dashes off to U.A. After being flung into the air, Kurogiri decides to warn Tomura and warps himself away.

The League of Villains' Upper Hand: All Might Appears!

Izuku, Tsuyu and Minoru witness Eraser Head's defeat.

At the Central Plaza, the severely beaten Shota tries to get up but Nomu pins him down. Kurogiri appears before Tomura, telling him that Thirteen is defeated but he could not stop one of the students from escaping, much to Tomura's frustration. Realizing that the escaped student will most likely go and find dozens of pro heroes whom they will not be able to defeat, Tomura decides to retreat.

Izuku's punch impact is absorbed by Nomu.

However, after seeing Izuku, Tsuyu, and Minoru, Tomura says that before they retreat, they will knock the Symbol of Peace's pride down a notch and decides to attack the students. Tomura reaches out towards Tsuyu's face to disintegrate her, but Shota uses all his remaining strength to nullify Tomura's Quirk before being pinned down again by Nomu. Izuku attacks Tomura although Nomu intercepts it. Izuku notes that his punch was successful but realizes that it had no effect on Nomu.

All Might quickly defeats multiple villains.

Izuku and Tsuyu get into a brief scuffle with Tomura and Nomu. Suddenly, the doors of the USJ burst open, revealing All Might in the flesh, telling everyone to have no fear since he has arrived, much to Class 1-A's happiness. Tomura decides to continue their mission.[7]

All Might says that he knows what is going on due to running into Tenya along the way. All Might rips his tie and takes off his blazer. All Might uses his super-speed and instantly defeats the remaining villains in the Central Plaza, then goes to pick up the beaten Shota. Using his super-speed again, All Might rescues Izuku, Tsuyu, and Minoru from the clutches of Tomura and Nomu. All Might then puts them down at a safe distance, telling the three to go to the entrance and leaves Shota in their hands. Izuku tries to warn All Might about Nomu but All Might tells him it is all right.

All Might vs. Nomu

The Villains trap All Might.

All Might begins his battle with the League of Villains, attacking Nomu with a Carolina Smash, but Nomu retaliates with a punch, which All Might dodges and counters. At this point, All Might realizes that his attacks are having no effect. All Might grabs Nomu and uses a suplex, smashing Nomu into the ground.

Kurogiri intervenes, using his Quirk to save Nomu and allowing Nomu to turn the tables on All Might by grabbing onto his weak spot. Kurogiri prepares to carry out his duty to eviscerate All Might. Izuku, seeing All Might in trouble, decides to help his mentor and rushes to him. Suddenly, Katsuki appears, using an Explosion on Kurogiri, and then grabs his plates which pin him down. Shoto appears and freezes half of Nomu's body and Eijiro tries to attack Tomura but Tomura dodges him.[8]

The students arrive to aid All Might.

Thanks to Shoto freezing half of Nomu's body, All Might escapes from Nomu's grasp. Katsuki continues to hold Kurogiri down, warning him not to try anything funny. Tomura orders Nomu to take out Katsuki and recover their gateway. Nomu gets up from the ground but his frozen half shatters in the process. However, Nomu starts to regenerate his wounds and returns to normal. Nomu attacks Katsuki, but All Might protects Katsuki from Nomu's attack. In the process, Kurogiri is freed from Katsuki's clutches and returns to Tomura's side.

After seeing All Might protect Katsuki, Tomura begins to talk about violence; that both Heroes and Villains use violence to protect their respective comrades. He continues to say that the title "Symbol of Peace" is nothing more than an oppressive form of violence, accusing All Might of using the title to create more violence, but All Might calls it rubbish. All Might and Nomu attack each other and engage in a fistfight. All Might decides to surpass his 100% after seeing that his attacks are having minimal effect. All Might launches a devastating punch against Nomu, sending Nomu flying out of the USJ, defeating him. Seeing his main upper hand-blown out of the USJ, Tomura starts to tear up.[9]

Game Over for the League of Villains

Denki is taken hostage.

At the Mountain Zone of the USJ, Denki is suddenly taken hostage by one of the villains who was unaffected by Denki's discharge, forcing Momo and Kyoka to surrender as they can do nothing now that one of their classmates have been taken hostage.

At the Central Plaza, All Might has defeated Nomu. All Might asks Tomura why he is not going to fight as it is his mission to kill him. Tomura starts panicking as without Nomu they have no chance against All Might. Kurogiri tells Tomura to calm down as Nomu has dealt significant amounts of damage to All Might, saying they still have a chance to complete their mission. Tomura regains his composure and decides to finish what Nomu started. Kurogiri and Tomura charge at a taunting All Might (who is unable to move due to Nomu causing him too much damage). As All Might internally panics, Izuku uses One For All on his legs and jumps towards Tomura and Kurogiri to intercept them. As Izuku prepares to clash with Tomura and Kurogiri, Tomura is hit by a gunshot, causing him and Kurogiri to stop their attack on All Might.

Tenya comes back with the teachers.

At the Mountain Zone, the villain holding Denki hostage is shot down, freeing Denki. It is revealed that the gunshots came from one of the U.A. pro heroes that have arrived to help along with Tenya who called them to help. Now that the U.A. Pro Heroes have arrived, Tomura declares that it is officially game over for them. Surprisingly, the heavily damaged Thirteen shows up, using Black Hole on Kurogiri and Tomura. Before being sucked away by Thirteen, Tomura says that although they failed this time, they will definitely kill All Might next time. Both Kurogiri and Tomura are sucked into oblivion.

Class 1-A's Victory: The League of Villain's Defeat

The defeat of Kurogiri, Nomu, and Tomura end the League of Villains' attack with Class 1-A as the victors. Izuku laments that he was unable to do anything, but All Might cheers Izuku up, saying that if it was not for Izuku, he would have been dead.[10]

The U.A. Pro Heroes decide to go and check the conditions of the students and the teachers that fought the League of Villains. Eijiro goes to see if Izuku is all right, but the pro hero Cementoss creates a cement wall to stop Eijiro from seeing All Might's true identity, Cementoss tells Eijiro that the U.A. pro heroes want to check the students for injuries, telling him to go to the front gate of the USJ along with his classmates. All Might thanks Cementoss for concealing his identity, to which Cementoss replies that they should head to the infirmary to have his wounds treated.

Tomura talks to "Sensei".

At the League of Villains' hideout, a portal opens up, with Tomura and Kurogiri exiting it. They both survived due to Kurogiri warping himself and Tomura just before they were sucked into oblivion and thus saved themselves from being killed. Tomura is on the floor groaning about his body hurting, moans about Nomu being defeated and his subordinates being routed. Tomura further complains that All Might is still alive and tells someone that he was wrong. On the blank monitor, a mysterious person tells Tomura that he was not wrong and that he was simply over-optimistic. The mysterious person asks where Nomu is. Kurogiri regretfully informs that he could not locate Nomu's coordinates and thus he could not save him. The mysterious person says that it is too late to mourn and that they should gather a new group hand-picked for efficiency, saying that they should take all the time they need. The mysterious person says that Tomura is a symbol of importance and that next time he will show the world the horror of his existence.

Bright Future for the New Generation of Heroes

"And the students of 1-A will make fine heroes!"

Outside the USJ, Class 1-A have gathered to see if they have any injuries, but it is revealed that everyone (except for Izuku) is uninjured. Class 1-A begin speaking amongst themselves about their experience in facing villains. Tsuyu asks Detective Naomasa Tsukauchi how their teachers and Izuku were doing, to which he replies that they are in critical condition but are not in any life-threatening positions. As Naomasa leaves for the infirmary, one of the policemen says that they have apprehended a suspect 400 meters from the USJ.

At the nurse's office, Naomasa arrives and tells All Might that Shota and Thirteen will be all right. He then says that if it was not for them, the children would have been most likely severely injured. However, All Might says that the students fought bravely and made the villains look like fools, saying that Class 1-A will make fine heroes.[11]

One Battle Ends, Another Battle Begins

The next day in Class 1-A, Tenya tells his classmates to be seated. To everyone's surprise, Shota walks in bandaged all over. He tells his students to not worry about him and that the battle has not really ended for them, saying that their next battle is the approaching U.A. Sports Festival.[12]

Story Impact

  • Tenya Ida becomes the Class 1-A president while Momo Yaoyorozu becomes the Vice-President.
  • All of Class 1-A get their first real-life experience of the world of Pro Heroes.
  • All Might starts to weaken dramatically.
    • Eraser Head's Quirk is also weakened because of his fight with Nomu.
  • One of the major antagonists, Tomura Shigaraki is introduced.
    • The organization that Tomura is from, the League of Villains, is also introduced and the mission of the villainous organization is to kill All Might.
    • The mysterious individual that Tomura seems to regard as the leader, Sensei, is shown through voice.
  • Izuku has his first fight with a villain with assistance from his classmates and wins.
    • Izuku uses One For All for the first time without damaging his body. He believes he did this by reflexes.
  • The first villain as strong as All Might, Nomu appears.
    • It is revealed later on that Nomu is an Artificial Human experimented on by the League of Villains.
  • Eijiro Kirishima slowly starts a friendship with Katsuki Bakugo.

Characters Introduced

Quirks Introduced

  • Hardening: Eijiro's Quirk gives him the power to harden and sharpen any or all parts of his body, causing his flesh to become jagged and rock-like.
  • Creation: Momo's Quirk gives her the ability to create any non-living material/object from her exposed skin by transforming the molecular structure of her fat cells.
  • Pop Off: Minoru's Quirk allows him to produce and pluck ball-shaped objects from his head; the balls grow back just as fast as they're plucked.
  • Black Hole: Thirteen's Quirk allows her to replicate a black hole suction effect from her fingertips.
  • Homing: Snipe's Quirk allows him to control the trajectory of any and all of the bullets he shoots.
  • Cement: Cementoss's Quirk allows him to manipulate any cement-based material that he touches, allowing him to shape it into various forms.
  • Decay: Tomura's Quirk allows him to disintegrate whatever he touches with all five fingers.
  • Warp Gate: Kurogiri's Quirk grants him the ability to create and manipulate a dark fog that from his head and hands. This fog acts as a portal to another location.
  • Shock Absorption: The Nomu's Quirk grants him the ability to absorb the shock of any attack, but he has a limit to how much he can absorb.
  • Super Regeneration: The Nomu's second Quirk grants him the ability to regenerate from severe injuries in seconds. He can even regenerate whole limbs.
  • Clones: Ectoplasm has the ability to create clones from the ectoplasm he shoots out from his mouth.
    • It should be noted that this Quirk would not be shown in the Manga until the Final Exams Arc.
  • Voice: Present Mic has the ability to raise the volume of his voice into a concussive sonic blast.
    • It should be noted that this Quirk would not be shown in the Manga until the Final Exams Arc.
  • Electric Charge: Tesla has the ability to harvest electricity from the air and utilize it. He can also disrupt signals.
  • Chameleon: Invisible Wall has the physical characteristics of a chameleon, allowing him to walking on walls and camouflage his body.
  • Water Control: Hanzo Suiden has the ability to manipulate and weaponize water.
  • Hair Control: Needle Hair has the ability to manipulate her hair.
  • Iron Claws: Sickle Claw has long metal-like claws on his fingers.
  • Curse: Thousand Eyes has the ability to make its body like paper, allowing it to attack with paper strands and making its body very light weight.
  • Body Morph: Steel Bulwark has an extra pair of arms and he is very strong.
  • Mutant Bovini: Stitched Giant has the ability to shoot laser beams from his face.
  • Plant: Chomper has the ability to grow plant structures from his body.
  • Hair Control: Martial Hair has the ability to manipulate and weaponize her pigtails.
  • Charging Muscles: Muscle Man has the ability to charge up short bursts of strength in his muscles.
  • Muscle Expansion: Hard Head has the ability to expand his muscles to increase his strength.
  • Bull Head: Minotaurus has a pair of horns on his head.
  • Extra Arms: Four-Armed Zealot has an extra pair of arms.

Battles & Events

Battles & Events


  1. My Hero Academia Manga and Anime: Chapter 12 and Episode 9.
  2. My Hero Academia Manga and Anime: Chapter 13 and Episode 9.
  3. My Hero Academia Manga and Anime: Chapter 13 and Episode 10.
  4. My Hero Academia Manga and Anime: Chapter 14 and Episode 10.
  5. My Hero Academia Manga and Anime: Chapter 15 and Episode 10.
  6. My Hero Academia Manga and Anime: Chapter 16 and Episode 11.
  7. My Hero Academia Manga and Anime: Chapter 17 and Episode 11.
  8. My Hero Academia Manga and Anime: Chapter 18 and Episode 12.
  9. My Hero Academia Manga and Anime: Chapter 19 and Episode 12.
  10. My Hero Academia Manga and Anime: Chapter 20 and Episode 13.
  11. My Hero Academia Manga and Anime: Chapter 21 and Episode 13.
  12. My Hero Academia Manga and Anime: Chapter 21 and Episode 14.

Site Navigation