Battle Trial Arc

The Battle Trial Arc is the third story arc of My Hero Academia and the third within the U.A. Beginnings Saga, covering chapters eight through eleven and episodes six through eight. It sits between the Quirk Apprehension Test Arc and the U.S.J. Arc.

Its premise is a training exercise: the students are drawn into pairs by lottery and set against one another in mock raids, one team defending a target and the other trying to take it. The scenario doubles as the first proper test of the costumes each student designed, and as the first head-on collision between Izuku Midoriya and Katsuki Bakugo now that both attend the same school on the same footing.

Beyond the exercise itself, the arc introduces the shadow that will hang over the series, closing on an unnamed figure reading about All Might's new teaching post and wondering aloud what would happen if the Symbol of Peace were extinguished.

Newly costumed, Class 1-A assembles at Ground Beta, where All Might lays out the rules. Two students play villains guarding a nuclear weapon they intend to deploy, two play heroes trying to stop them. The heroes win by capturing their opponents or reaching the core before time expires; the villains win by holding the core or capturing the heroes. The opening draw sends Izuku and Ochaco in as heroes against Katsuki and Tenya.

Katsuki ambushes the pair almost immediately, but Izuku anticipates which arm the attack will come from, having taken exhaustive notes on Katsuki years earlier, and flips him to the floor. He declares he is no longer the Deku who could be pushed around, which does nothing for Katsuki's temper. Izuku sends Ochaco ahead and keeps Katsuki occupied, dodging on the strength of his analysis while retreating to think. Upstairs, Ochaco reaches the core and hides, but a giggle at Tenya's theatrical villain act gives her away, and he reveals he has scrubbed the floor clean specifically to deny her anything to lift.

Cornered, Katsuki reveals his gauntlets store his sweat and unleashes a blast large enough to gut part of the building. All Might warns that another one ends the exercise in a forfeit, so Katsuki closes to fists, redirects himself with explosions to get behind Izuku, and slams him down. With no options left, Izuku commits to One For All and drives Detroit Smash into the ceiling. The blast rips through the floor Ochaco and Tenya are on; she anchors herself to a pillar, batters Tenya with floating debris, and takes the core. The hero team wins.

Afterward All Might tells Katsuki to look back honestly and move forward. In the monitor room, Momo explains why Tenya performed best: the enormous ranged attacks were reckless indoors, Ochaco lost focus partway and gambled at the end, while Tenya adapted and built a counter-strategy. The next bout ends quickly, with Shoto freezing an entire building and taking the core unopposed to win alongside Mezo.

At the nurse's office, Recovery Girl scolds All Might for letting his disciple wreck himself a third time and demands he mentor the boy properly, prompting All Might to defend the necessity of a Symbol of Peace. Izuku later seeks Katsuki out and admits the truth, that the power was given to him and he has not been lying for years, but Katsuki dismisses it and declares he will be number one, telling All Might he intends to surpass him too. Elsewhere, a stranger reads about All Might's move into teaching and asks what the world would look like if villains snuffed the symbol out.

The trial marks the debut of the class's hero costumes, built from designs the students submitted themselves; Izuku's is destroyed by Katsuki here and stays broken until the Vs. Hero Killer Arc.

Katsuki's defeat is the first real crack in his assumption of superiority, and the humiliation carries forward into his classmates teasing him during the bus ride to the U.S.J. Izuku's win, achieved through preparation and teamwork rather than raw power, earns him standing among his classmates. His hint about where his Quirk came from appears to bounce off Katsuki entirely, though the Provisional Hero License Exam Arc later reveals it did land. Meanwhile, Shoto's casual dominance registers with Katsuki as a threat, seeding the rivalry that surfaces at the U.A. Sports Festival.

The arc introduces Tomura Shigaraki, Kurogiri, and the U.S.J. Nomu, and establishes that a band of villains is now organizing around the goal of destroying All Might. It also debuts a large share of Class 1-A's Quirks, among them Half-Cold Half-Hot, Dupli-Arms, Tail, Invisibility, Acid, Tape, Dark Shadow, Earphone Jack, and Electrification.