All For One allows the user to steal other people's Quirks and wield these stolen powers as their own or to transfer them to someone else.
The process of giving and taking away Quirks is done through touch. People who have their Quirks stolen become Quirkless, losing any sort of abnormal features if they happen to be Mutant types. Meanwhile, Quirkless people who receive a Quirk through All For One become capable of manifesting all of its attributes.
However, not all recipients of a Quirk from All For One are able to handle the strain of gaining them. Subsequently, they may become mindless dolls, who are not able to speak or think for themselves. Rarely, a Quirk granted by this ability can blend together with the original Quirk of the target, creating an entirely new one, as shown with One For All.
All For One can be used to combine several Quirks in order to create devastating techniques, which would normally not be possible with the usage of only one Quirk.
There are some limitations to the Quirk. The effectiveness of the Quirks that are stolen by All for One depends on his own abilities. He stated that he did not want to steal Best Jeanist's Fiber Master, as it required too much training and experience to truly master, and implies that he only steals Quirks with straightforward abilities. Additionally, All for One is incapable of stealing One for All from its wielder, as that Quirk can only be passed on if the present wielder wills it. Thus, wielders of One for All can act as a natural counter of sorts against All for One's ability to steal other Quirks. However he was able to overcome this limitation in the past against at least two wielders of One for All, due to the sheer number of Quirks he possessed.
The man who wields All For One once used his Quirk to dominate Japanese society over a century ago, using his Quirk to take away unwanted Quirks and give them to those who needed it, in exchange for favors. Eventually, All For One's user would amass a large following of loyal subordinates that carried every single one of his wishes.
Later, this man would use All For One to empower artificially-made monsters known as "Nomu" in order to assist Tomura and the League of Villains with the achievement of their goals. Even after his arrest, however, Nomus with access to various Quirks are still being produced somehow, and his role in this scheme, assuming he has any, is not yet known at the moment.
For combat, All For One's user prefers to combine many of the Quirks he has collected through his life in order to maximize their power and effectiveness, often to truly catastrophic levels. Since this man has no qualms with killing, he doesn't hold back in fights, and will even target defenseless people, using them as a distraction to his advantage.
It's been suggested by All Might that All For One was used to obtain a Quirk that grants agelessness, potentially explaining how its user is still alive to this day.
- One For All's name is an inversion of All For One, showing the differing philosophies between their wielders. The former emphasizes one using their power for the betterment of others while the latter is meant to selfishly hoard power for one's own sake.
- All For One is the oldest known named Quirk in the series.
- ↑ My Hero Academia Manga: Chapter 93.
- ↑ My Hero Academia Manga: Chapter 94.
- ↑ My Hero Academia Manga: Chapter 89.
- ↑ My Hero Academia Manga: Chapter 59.