All For One (Quirk)

All For One is the Quirk used by a mysterious villain who names himself after it, as well as the man's successor, Tomura Shigaraki.

A weaker version of the Quirk was also used by Nine.

## Usage

All For One allows the user to steal the Quirks of other people and wield those stolen powers as their own.

It also allows the user to redistribute stolen Quirks to someone else.

The process of giving and taking away Quirks is done through touch.

A victim whose Quirk has been stolen becomes Quirkless, and loses any abnormal features if the powers happened to be Mutant-types.

Interestingly, even if the user holds Mutant-type Quirks, the subsequent features do not permanently manifest on the user's body, and they can instead summon the mutant features at will.

Additionally, when a Quirk is stolen, the victim becomes disoriented and immobile for a short time.

Meanwhile, Quirkless people who receive a Quirk through All For One become capable of manifesting all of its attributes.

Rarely, a Quirk granted by this ability can blend together with the recipient's original Quirk, creating an entirely new power, 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.

All For One's first user intended to have Tomura inherit his Quirk, implying that transferring All For One itself to another person is possible.

This was evinced to have already been accomplished, as All For One, prior to being sent to Tartarus, had Doctor Kyudai Garaki extract his power from his body, and duplicated, with the original being kept on standby to be passed on to Tomura, while the Symbol of Evil retains the copied version of his original Quirk.

It has been shown that the recipient of the All For One Quirk itself can access the Quirks that the previous user possessed due to the said powers becoming applications of All For One, rather than extra Quirks.

Another facet of receiving this power is having a mental link with the previous user, whose psyche was imprinted onto the All For One Quirk.

As a result, Tomura exhibits some of his master's personality traits, and can meet with a vision of All For One within his own mind.

This is similar to how the wills of the One For All users are integrated into One For All itself, which has evolved to where Izuku Midoriya can loosely communicate with the previous inheritors of the said power.

It was soon revealed that both cases are due to the common spectacle that Quirks, much like organs during organ transplants, retain the consciousness of their donor, whose power was granted to the recipient.

All For One seems to grant access to an unidentified mental realm contained within the Quirk similar to its counterpart Quirk, One For All, as shown when Tomura tried to steal One For All from Izuku.

When this happened, the mental realms of both Quirks became connected temporarily and the current users, and the stored consciousness of previous users, were shown inhabiting the same mental realm.

## Weakness

There are some limitations to the Quirk.

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.

Being Quirk-empowered prior to receiving a Quirk from All For One is a factor that allows a person's body can withstand the Quirk-bestowal process.

This spectacle was evident when Yoichi Shigaraki and Wolfram were not put into brain-dead states upon being endowed with a Quirk by All For One, due to already being in possession of their own respective Quirks.

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 prefers to steal Quirks with straightforward abilities.

All For One is incapable of stealing One For All from its wielder, as that Quirk, by its very nature, 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 previous wielders of One For All, due to the sheer number of Quirks he possessed.

Furthermore, Kyudai performed various experiments on the body of Tomura so that the latter can be capable of stealing One For All, a feat All For One himself couldn't accomplish.

It was eventually revealed that One For All's anti-theft properties can be overridden by someone with strong negative emotions, due to it eating away a potential inheritor's will.

The wills of the previous One For All users surmised that All For One has been grooming Tomura's body and hatred in order to override One For All's will and finally steal it in that manner.

It's been discussed by Kyudai that, over time, the large number of accumulated Quirks within All For One was becoming dangerous to the user himself.

While it seemed that All For One could allow the user to safely control any number of Quirks, there is a limit to how much the user can control without it adversely affecting them, like the Nomu.

Kyudai went on to state that if the "memory" (the amount of power of a Quirk) exceeds the hardware (the body of the Quirk user) then it will cause serious problems.

This is somewhat similar to One for All, which causes a serious burden on the user's body and can shorten their lifespan if they already possess a Quirk when receiving it due to the burden of possessing multiple Quirks.

The body strain drawback of this Quirk was displayed during the Paranormal Liberation War, when Tomura's body began to suddenly tear apart despite having Super Regeneration, which activated shortly afterwards. Tomura was intended to awaken with his newly enhanced body within 4 months, but was forced out of stasis early due to Mirko shattering his capsule, leaving him at 75% of his intended strength.

Due to this premature emergence and insufficient power, Tomura's body couldn’t keep up with the power of All For One and the multitude of Quirks stored within it.

While all Quirks are tied to the user's body and have been stated to be a function of the user's physiology much like an organ or limb and as such injury or negative health conditions will limit a user's Quirk or ability to use their Quirk, this is even more pronounced in All For One.

As the ability to use stolen Quirks along with how many Quirks can be stolen is directly connected to the health and strength of the user's body, the user's ability to steal Quirks and use them is drastically diminished if they become injured or crippled.

After his fight with All Might, All For One's permanent, life-threatening injuries drastically reduced his power and output with his Quirk forcing All For One to come up with a way to either heal himself or strengthen and take a new body to recover and surpass his previous limits.

While not an issue for the original wielder of the Quirk, one particular weakness of All For One is that an inheritor of the original Quirk variant is the threat of the previous wielder's will taking over the body and controlling the current user as is the case for Tomura being taken over by All For One.

As described by the vestigial will of All For One contained within the Quirk, negative emotions such as hatred and anger would allow his consciousness to take over the body of its current wielder.

With Nine's lower-tier variation of the Quirk, he was only able to steal up to 8 other Quirks.

In his attempt to steal One For All from Izuku Midoriya, Nine was unable to do so, which he believed was due to his storage limit (which was actually the Quirk's anti-theft properties).

It's unknown if Nine's version allowed him to transfer Quirks.

Moreover, due to the power of All For One, it put further strain on his body and caused the cellular degeneration from his Weather Manipulation Quirk to worsen.

This drawback is the reason why Nine attempted to steal the Cell Activation Quirk of Katsuma Shimano so that he can rejuvenate his lost cells and continue using his various Quirks without limit.

## Users

* All For One (Formerly)
* Nine (Formerly)
* Tomura Shigaraki (Currently)