Yoichi Shigaraki

Frailty defined him from birth, leaving a body that looked malnourished and never gained strength. White hair reached roughly to his shoulders and fell in the same unkempt way Tomura Shigaraki's does, the bangs usually hiding bright green eyes.

His wardrobe stayed plain throughout his life: a white shirt, dark trousers, and now and then a light blue jacket.

His body was weak and his convictions were not. Justice mattered to him in a way that put him permanently at odds with Zen's ambition, and he tried repeatedly to stop his brother from killing people for their abilities, taking abuse for the trouble. Even so, he held onto a vague memory of an infant hand around his and refused to write Zen off entirely. Comics were what the two of them shared, and Yoichi loved that stories could be told in pictures, the Captain Hero series most of all, inspired by its heroic lead.

Jealousy drove Zen to kill the Luminescent Baby, after which he announced that he meant to rule the world, cast himself as the Demon Lord from those same comics, and lifted the name All For One straight out of the series. Whatever hope Yoichi had died there. He would not be recruited no matter how often his brother dismissed his beliefs as ridiculous idealism, and he resisted being handed a Quirk at all, refusing a power torn out of somebody else.

He does not hate All For One so much as grieve him, disgusted by the selfishness and haunted by the idea that a power able to give as well as take might have been the most charitable thing the world would ever know. Toward his successors he is friendly, and Izuku Midoriya he regards highly, moved by a boy who extends help even to his enemies. He talked Kudo and Bruce into accepting Izuku by reminding them that they had once meant to kill him too and reached out to save him instead, calling them his heroes for it. When Katsuki Bakugo brought All For One down, Yoichi neither celebrated nor felt relief, only grief at where his brother's choices had led him, and he stayed beside the Vestige to the very end, apologizing for failing to steer him right. In those last moments the Demon Lord facade crumbled and a lonely man shouted at his brother not to disappear, before Izuku, Tomura, and the other successors destroyed them both and ended the conflict for good.

Born as Meta Abilities were first surfacing, Yoichi grew up presumed Quirkless and could only watch his older twin commit atrocities. Convinced his brother was powerless, All For One forced Power Stock into him, a stockpiling ability picked specifically because a weak body could survive it. What that revealed was that Yoichi did have a Quirk after all, one with no function beyond passing itself to another person. The two merged, and One For All existed.

Quirk Bestowal transferred through a sample of his DNA and only when the current holder chose to give it up, which is exactly why All For One could never steal it, though the recipient's agreement was never required. It had been so weak and unformed that it never manifested, hence the misdiagnosis. Because Quirk Factor types run in families, it carried the same assimilating property his brother's Quirk had, and All For One confirmed that it absorbed Power Stock to compensate for the strength it lacked. Yoichi's condition made the stockpile useless in his own hands, so handing it onward became the plan, in the hope it would grow.

Resistance leaders Kudo and Bruce broke him out. All For One found him regardless and killed him in a possessive rage, at which point the Quirk passed to Toshitsugu Kudo and started the chain of successors sworn to stop his brother. His will lived on inside it. Mental fortitude was always his real strength. Decades on, with All For One and Tomura trying to rip One For All out of Izuku, he and Nana Shimura pushed back inside the vestige world, and even Tomura was stunned by the willpower that expelled them and wrecked the attempt. The name Yoichi came from All For One, marking the first thing anyone had ever given him.