WARNING: The following contains spoilers for My Hero Academia Chapter 310, "Masters And Pupil,” by Kohei Horikoshi, Caleb Cook and John Hunt, available now in English from Viz Media.
Chapter 310 of the My Hero Academia manga fully reveals the second and third users of One For All for the first time, completing the Quirk's known lineage. The second and third have always been depicted as formless shadows, but now their vestiges have appeared for a specific reason: to help Deku unlock One For All’s true power. Here's everything we now know about the two mysterious predecessors.
They Had an Awkward Introduction
When Deku first meets all the vestiges of One For All, the second and third users are standing in the background staring at a wall. In the circle where all the other vestiges sit, there are two empty chairs -- it almost seems like the second and third are embarrassed about their past, and refuse to sit with the rest. They don’t say anything until Deku’s true resolve is tested. Yoichi, One For All’s first wielder, seems to be the only one the second and third will talk to, and he convinces them to believe in Deku.
They Were Alive in the Dark Era
The second and third users were alive during the height of All For One’s prosperity. He was too powerful for authorities to handle, and his control over society went unchecked. Those were darker times in the My Hero Academia world, where villains held the power and Heroes were seen more as survivors. It seems like the official title of Hero was not established yet, since there weren’t any real beacons of hope society could gravitate to.
The Second User was the “Leader” of the Rebellion
The third user refers to the second as the “leader,” as if to imply that he was the leader of a former rebellion. He states that they were gathering “allies,” meaning different factions were trying to figure out a way to rebel against All For One. The second must have been powerful indeed if he was the leader of the force that fought back, but like many wars, he lost numerous allies in battle. The loss was greater than the gain, and the defining scar on the second’s face was most likely received during his last encounter with All For One.
Clues to What Their Quirks Could Be
The third user has not given any clues on what his potential Quirk could be, but the second user has -- and it strikes a surprising resemblance to a UA High student. The second has gauntlets around both arms that are used as fire arms. It is still unclear what fuels his ammunition, but this could be a tease to Bakugo’s Quirk. The two share physical similarities as well, so it wouldn’t be surprising to learn the second has some iteration of Bakugo’s Explosion abilities.