Yoichi Shigaraki

Yoichi is compassionate, idealistic, stubborn, and deeply committed to the idea that power should protect rather than dominate.

As a child, he loves comic books about heroes and believes that stories of people rescuing others express hopes worth pursuing in real life. His brother interprets the same stories from the opposite perspective, admiring the Demon Lord who rules through fear.

Yoichi continues resisting despite being physically incapable of defeating his brother directly. Even after years of abuse, he struggles to completely abandon the hope that some trace of humanity remains inside the person who raised and controlled him.

His later interactions within One For All show the same compassion. He advocates for Izuku Midoriya when some previous users initially distrust the boy's determination to save even his enemies.

Yoichi originally possesses a seemingly useless Quirk whose sole function is allowing itself to be transferred to another person.

All For One, believing his brother Quirkless, forcibly gives him a separate Quirk capable of stockpiling physical power.

The two abilities merge inside Yoichi, creating One For All: a transferable Quirk that accumulates strength as it passes from one bearer to another.

Yoichi's frail body prevents him from exploiting the stockpiled physical power to the degree later users achieve. His importance lies instead in beginning the succession through which One For All can grow strong enough to oppose his brother.

Yoichi initially appears as a mysterious figure within the history of One For All.

His past gradually explains why One For All and All For One are fundamentally connected. He grows up during the chaotic emergence of Meta Abilities while his brother accumulates followers by stealing, redistributing, and manipulating Quirks.

Later revelations establish that Yoichi and All For One were twins born at the dawn of the Quirk era, with Yoichi chronically malnourished because his brother absorbed most of their mother's nutrients before birth.

Yoichi is eventually helped by Toshitsugu Kudo and Bruce, resistance fighters opposing All For One.

Yoichi passes One For All onward after escaping his brother's control, beginning the chain of successors whose shared objective becomes defeating All For One.

All For One is Yoichi's older brother and lifelong opposite. Yoichi condemns his cruelty while continuing to recognize him emotionally as family.

Toshitsugu Kudo reaches out to Yoichi and becomes the second bearer of One For All.

Bruce participates in the resistance that helps free Yoichi from his brother.

Izuku Midoriya becomes the ninth bearer of One For All and earns Yoichi's support through his determination to save people others consider beyond rescue.

Nana Shimura, Daigorou Banjou, and the other successors share Yoichi's vestige within One For All.