U.A. Traitor Arc

The U.A. Traitor Arc is the twenty-first story arc in My Hero Academia, and the third story arc in the Final Act Saga.

The pieces are in place and Class 1-A and the remaining Pro Heroes are preparing for the final fight to take down All For One, Tomura Shigaraki, and the rest of the League of Villains/Paranormal Liberation Front for good. However, things become complicated when the fabled "U.A. Traitor" suddenly emerges...

Story Impact

 * All Might reveals to Class 1-A that Star and Stripe's New Order Quirk has destroyed several of Tomura's Quirks after he stole it, giving them and the rest of the Heroes time to prepare to deal with the remaining threats.
 * These threats include: Tomura, All For One, Dabi, Himiko Toga, the six Near High-End Nomu, the remnants of the Paranormal Liberation Front, and the remaining escaped convicts, in addition to any additional allies they may gain.
 * It is revealed that since the end of the War, the students of Class 1-A had continued their training with the Wild, Wild Pussycats to get stronger.
 * "Tomura" is forced back on standby to allow his damaged Quirk Factors to heal.
 * Tomura and All For One's minds continue to fuse together, sharing their feelings of hatred.
 * Himiko is revealed to have reunited with the League.
 * Dabi remains impatient, wanting to go after his father again, before being talked down by All For One.
 * All For One confirms that he has a mole within U.A.
 * Class 1-A continue their training.
 * Katsuki Bakugo has developed a new technique to make use of his Cluster move, saving up a bunch of sweat for a barrage of explosions, all while wearing his winter costume.
 * Shoto Todoroki has reached the point where control over his left side has caught up to his right, so now he's focusing on using both at the same time.
 * Gigantomachia is confirmed to still be tied up and unconscious.
 * The "U.A. Traitor" is revealed to be Yuga Aoyama.
 * He was born Quirkless, and with his parents both coming from wealthy backgrounds, they made a deal with All For One to give him his Navel Laser Quirk in a desperate move to grant their son a happy, successful life.
 * He possessed the Quirk for ten years, which was incompatible with his body.
 * Because of the deal, the Aoyamas were forced to comply with All For One's orders against their will, or else they would face dire consequences.
 * All For One told Yuga to enroll in U.A. after learning All Might would become a teacher.
 * He provided information aiding in isolating the class during the U.S.J. Incident, as well as providing the location of the Summer Training Camp.
 * His parents receive another order from All For One, for Yuga to isolate Izuku Midoriya away from everyone, tearfully apologizing to him to do it.
 * Toru Hagakure and Izuku overhear the Aoyamas discussion and confront him, as he tearfully confesses to the truth.
 * Izuku restrains Yuga and his parents before they can escape.
 * Toru's face is briefly revealed for the first time in the confrontation.
 * Class 1-A, the U.A. Staff, and the Police Force discover the truth about the Aoyamas, where they are put under interrogation.
 * The Aoyamas reveal All For One's threats of death were they to say anything to the Police.
 * Izuku extends his hand to Yuga, stating he knows he never had any villainous intentions, proclaiming he can still be a hero.
 * Class 1-A states their intentions of wanting to forgive Yuga for his actions so he can help them take down All For One.
 * Shota Aizawa sides with his class, coming up with a classified plan to make use of Yuga.
 * The Aoyamas are taken to Central Hospital for further study.
 * Izuku and Tenya Ida encounter Mei Hatsume again at the Development Studio to fix up their hero costumes.
 * The Support Course is revealed to be in charge of developing and maintaining the U.A. Barrier.
 * Mei is in charge of creating new inventions to assist in the case of mass evacuation.
 * Mei creates a new makeshift Gauntlet out of the remains of Izuku's Mid-Gauntlets and his Air Force Gloves.
 * The Class 1-A Search Squad assembles to track down the remnants of the League of Villains and the Paranormal Liberation Front.
 * At the same time, a Counter-Force assembles at Central Hospital, consisting of All Might, Hawks, Ragdoll, Naomasa Tsukauchi, the Police Force, and Star and Stripe's American brothers-in-arms.
 * Their plan is to separate Tomura and All For One by at least 10 kilometers to prevent them from combining their power.
 * This also involves isolating each of the League's major operatives and taking them out one by one, so that they will be unable to assist either.
 * Yuga is interrogated by Shota, where it's confirmed he does not possess an explosive trap like Lady Nagant had.
 * Shota theorizes only people All For One had contact with after his defeat from All Might could potentially have an explosive trap within.
 * Shota manages to convince Yuga to help them fight back, telling him not to let the guilt ruin the rest of his life.
 * Hitoshi Shinso's hero costume is revealed.
 * Himiko visits her old family home, now abandoned and heavily vandalized, while reminiscing about her past.
 * Himiko leaves and encounters Dabi who questions if she's ready to help the villains bring an end to society before burning down her old home.
 * It is revealed that Dabi acquired a sample of Twice's blood during the War, and gives it to Himiko, allowing her to Transform into him and utilize his Double Quirk.
 * "Tomura" continues through his process of recovery.
 * It seems that the lost fingers on his left hand are starting to grow back.
 * Spinner reluctantly agrees to take the lead as the face of the Paranormal Liberation Front, to steer the heteromorph villains toward their cause.
 * Spies for All For One are revealed to be within U.A.'s walls, with the intention of spurring discourse amongst the public to drive Izuku out.
 * All Might, Naomasa, and Nezu inform Class 1-A of their plans for the second War.
 * At the same time, Hawks and Ragdoll inform Endeavor and Best Jeanist of said plans.
 * Nezu announces to the evacuees of Tomura's upcoming completion in 4 days.
 * Class 1-A move into a make-shift fortress "Troy" to prepare.
 * Izuku thanks Ochaco for her speech to the public.
 * The two of them trade their thoughts about wanting to understand Himiko and Tomura.
 * Shoto also talks about wanting to understand Toya.

Characters Introduced
No new characters have been introduced this arc.

Quirks Introduced
No new Quirks have been introduced this arc.