Roaring Muscles

Picking up on the tears that ended the previous chapter, All Might tells the stunned Izuku that he is fit to inherit the man's strength. The confusion clears once All Might explains the part nobody knows: his power can be passed from one person to the next, and he has settled on Izuku as the successor. The power has a name, One For All.

Izuku wants to know why him. All Might has no objection to giving it away, and says the boy outshone every so-called hero on the scene that day. The choice, he stresses, belongs to Izuku, who accepts.

Training starts immediately, because a body handed One For All in its current state would simply be torn apart. All Might sets him to clearing the trash off Takoba Municipal Beach Park, a ten-month program timed to end at the U.A. entrance exam, with the goal of turning Izuku into a proper vessel.

Izuku ignores the schedule almost at once, pushing himself into collapse. All Might chews him out for it, but the sheer drive to become the strongest hero moves him enough that he rewrites the plan around what Izuku actually is.

Ten months later, exam day arrives with Izuku's frame rebuilt into something lean and muscular, and All Might pronounces him a genuine vessel who earned his reward fairly. The handover itself is less dignified than expected: All Might plucks out a hair and tells him to eat it. Any route for the DNA works, he explains, and with only hours left before the exam the transfer has to happen now, since the DNA needs time to take.

One For All is introduced by name as All Might's Quirk.

Rather than being something a person is born holding, the power turns out to pass down by inheritance.

Izuku spends ten months in intense training to become a body capable of holding One For All.

Izuku swallows a single hair plucked from his mentor in order to receive the Quirk, with the U.A. entrance exam only hours away.

The second chapter of Kohei Horikoshi's series, printed July 14, 2014 in issue 33 of that year at twenty-five pages and collected in volume 1. It sits in the Entrance Exam arc and reached the anime as Episode 3.

Izuku Midoriya and All Might share the cover, matching the mentor-and-successor thread that drives the chapter. Settings include Musutafu, the Takoba Municipal Beach Park, Aldera Junior High, and the Midoriya apartment, with U.A. High School mentioned as the target.

Death Arms, the Sludge Villain, Katsuki Bakugo, and Inko Midoriya all surface briefly around the main story.