All For One

All For One, written オール・フォー・ワン and read Ōru Fō Wan, is the Emitter Quirk that lent its name to the villain who first held it. It works by contact and enters the story in Chapter 59 of the manga and Episode 33 of the anime.

Three people have wielded it: its first owner, who eventually kept only a duplicate; Tomura Shigaraki, who received the original; and Nine, whose copy was markedly inferior to either. It stands as a deliberate inversion of One For All, a power that lends rather than takes.

The Quirk takes Quirks and gives them away, and lets its holder wield several at once. Both operations route through the hole set in the wielder's palm and need contact, or hands close enough to pass for it. Energy usually streams off the point of transfer, though the act can be done quietly enough that the victim never notices. Anyone stripped this way is left Quirkless, sheds the physical traits of a Mutant-type power if that was what went, and is briefly dazed and immobile. The wielder does not permanently manifest the mutations they collect, summoning those features only when wanted. Even an unformed Quirk Factor can be taken, as the infant Tenko Shimura discovered.

Now and then a granted Quirk fuses with what the recipient already carried and yields something new, the way Yoichi Shigaraki's Quirk Bestowal met Power Stock and became One For All. Stored powers can also be stacked to reinforce one another or merged into attacks no single Quirk could manage. Bearing them is the hard part: recipients who cannot take the strain end up mindless dolls, and already owning a Quirk seems to be what carried Yoichi, Wolfram, and Lady Nagant through. Kyudai Garaki framed the wielder's own ceiling as memory against hardware, and exceeding it does real harm, as it did to Tomura, pulled from stasis four months early at 75 percent and later erupting in hundreds of hands under the Quirk Singularity.

Several limits hold firm. One For All cannot be taken from an unwilling holder, though sheer accumulated numbers let All For One manage it against earlier inheritors, and deep enough hatred erodes a successor's will and opens the same door, which was the entire point of grooming Tomura. The Quirk gives and takes but cannot delete, so when Star and Stripe seeded New Order with a rule to turn on his other powers, the only escape was passing it along. A power must also be pulled from its owner rather than from what they have already released, leaving Endeavor's flames and Fumikage Tokoyami's Dark Shadow untouchable. Worst of all, the original carries its previous holder's psyche, which can seize the body outright when rage gives it an opening, though a strong enough will can erase that vestige entirely.

Zen Shigaraki, the man who took the name All For One, manifested the Quirk moments after birth and instinctively stole his mother's Spearlike Bones as a newborn. He spent over a century ruling Japan from the shadows, stripping unwanted Quirks and granting them to the desperate in exchange for favors while hunting the strongest powers for himself; his brother Yoichi grieved that the same ability could have been the kindest force in the world. He fused many Quirks into single catastrophic attacks, built the Nomu with it, hid powers inside people without their knowledge including the self-destruct planted in Lady Nagant, and stayed alive for decades on Life Force taken from Kyudai Garaki. Before Kamino he had the Quirk duplicated, keeping the copy while Kyudai preserved the original for Tomura. The copy proved weaker, and during the Final War the vestiges of those he had robbed rebelled against him outright.

Nine received All For One's DNA during Kyudai's experiments and, proving compatible, gained a diminished version capped at eight Quirks, with no confirmed ability to grant any away. He hunted Pro Heroes for powers suited to close and distant fighting alike, then stalled at seven after failing against both One For All and the Cell Activation held by Katsuma Shimano, which he needed to halt the cellular decay his Weather Manipulation caused.

Tomura Shigaraki received the original through a long operation that left him holding every Quirk stored inside it, though at 75 percent completion he lacked both the strength to steal One For All and full command of what he carried. He pairs it with Decay, taking a power and then crumbling its owner, as he did to Star and Stripe. His grip on his childhood self as Tenko Shimura let him keep a foothold while his master's vestige drove his body, long enough to overwrite it and stand as the true successor. When his will faltered the vestige returned and destroyed him, until the Heroes and their predecessors annihilated that consciousness, handing his body back just before his death.