Quirk: All for One
Type: Emitter
Info: 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. All For One does not appear to have a limit about the number of Quirks that can be stolen or held to, although its user has mentioned that Quirks taken by him must be used "quickly" for some reason.
All For One's user hints that his wish is for Tomura Shigaraki(Tenko Shimura) to inherit his Quirk, implying that transferring All For One itself to another person is possible.
Usage
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 their 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 on 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 ever target defenseless people 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.
Quirk: One for All
Type: Emitter
Info: Long ago, a man with a Quirk that could steal Quirks and give them away, forcibly gave his seemingly Quirkless little brother a Quirk that allowed him to stockpile power within his body. However, the little brother already had a Quirk with no effect other than that it could be transferred to others. The little brother's Quirk and the Quirk given to him by his older brother merged and became One For All.
The little brother somehow discovered this. He had a strong sense of justice and he tried to defeat All for One, but given the huge difference in their abilities, the brother failed. The little brother decided to entrust the Quirk to future generations of heroes, hoping that they would cultivate One For All and one day, put a stop to All For One. Few knew the truth about One For All. The Quirk was passed down for nine generations, growing stronger with the passage of time. Currently One For All is one of the most powerful Quirks in existence, although it is quite difficult to master.
Description
All Might explains that One For All is the union of two Quirks: A Quirk that stockpiles power, and a Quirk that could be transferred to others. This mutation was caused by the Quirk, All for One.
One For All allows the host to access power from the previous users of the Quirk. It has not been shown if the Quirk that stockpiles power simply gains more energy as it is passed on (the first holder could not beat All For One, but a recent holder could, which suggests a power increase) or if it is able to imprint other Quirk abilities as it is passed from user to user and most believe that the people who use the Quirk use it in different ways.
One For All receives its name from the fact that it can be "inherited" by others; it is 'one' Quirk for 'all' people. Like a torch, it is passed on from person to person. The method of inheritance and transference of One For All is done by the recipient ingesting the current wielder's DNA, as shown with All Might giving Izuku Midoriya his strand of hair to ingest which let the latter inherit One For All.
One For All will not transfer to a new recipient unless its owner wishes for that to happen, thus it cannot be forcibly stolen. For example, the Hero Killer Stain ingested Izuku's blood but did not inherit One For All as Izuku was not even aware of such a condition. As One-For-All cannot be forcibly removed, it is the only quirk that can be used in combat against All-For-One, as any user of All-For-One would simply be able to remove the opponent's quirk to end the fight. However, this does not mean One For All cannot be forcibly passed on.
One For All also seems to alter the user's appearance in different ways. For Toshinori Yagi, it significantly enlarges his muscles and overall body mass to make him look like a completely different person similar to that of a giant. For Izuku Midoriya, usage of One For All causes the empowered part of his body to glow, with vein-like lines crossing through each other. His body also generates crackling green energy that resembles lightning bolts when he activates One For All: Full Cowling. It is unknown what the usage of One For All looked like for its previous handlers, however.
After One For All is transferred to the successor recipient, the predecessor can still utilize the "leftover embers" of One For All, and thus still access its power. However, these leftover embers will not last for long, and the previous One For All will slowly lose their access over the Quirk, resulting in the predecessor losing One For All completely. According to All For One, using these last embers continuously will rapidly increase the loss of the power. After All Might defeated All For One, the embers of One For All were burned out, and he cannot even maintain his muscle form for more than an instant, thus providing Izuku the full power.
Proper usage of One For All requires intense and rigorous training of the body to prevent the successor from being torn apart by the raw power flowing within their body. However, not every wielder is stressed the same, and some can get used to it rather quickly, as noted by Gran Torino, who went straight to actual combat training for All Might, since the latter did not take long to adapt to his then-new powers.
Izuku feels the previous users of One For All.
However, it is unclear what the true nature of One For All is. When Izuku was about to lose his match against Hitoshi Shinso, he suddenly felt the presence of multiple people coursing through his body and activated One For All to break free from Hitoshi's control. Izuku theorizes that since his Quirk is the "sacred torch that is passed down through the ages," those people that he felt were the lingering presence of those who had this power before him. He also mentions seeing someone with the same hairstyle of All Might among those who appeared in front of him, indicating that his presence is imprinted on the Quirk. All Might believes that it is just a sign of him being accustomed to One For All, it cannot communicate with the user or vice versa. Nana Shimura had theorized that the Quirk remembers all the wills of the predecessors as part of its power, although it still remains a mystery.
In a rare case, Izuku Midoriya was able to once again experience the traces of One For All, this time more clearly. In his dream form, almost all of Izuku's body is shrouded in what seems to resemble dark flames and his hair glows green. He also saw a memory of the first user of One For All confronting All for One. It is later revealed that the first user had intentionally shown the memory to Izuku. Long after his death, All For One's brother was still aware of Izuku being the ninth wielder of One For All and seems to have helpful intentions towards him. All Might believes that the ability to actually interact with previous users of One For All is exclusive to Midoriya.
With the right amount of stockpiled power, One For All grants its wielder many abilities, the most prominent being an immense strength, superior to that of most strength-enhancing Quirks, that allows one to fire blasts of wind through. It also increases the user's other physical attributes, such as speed and toughness.
Known Users and Usage
Previous One For All users seen in Izuku's dream.
One For All has been bestowed to nine different hosts in total, starting with All For One's younger brother. Alongside the Quirk, its origins and the story between the two brothers have been passed on too, since Toshinori Yagi, the eighth user, knew about them.
Because One For All can only be transferred willingly, it's presumed that each wielder had some form of personal connection with at least their corresponding predecessor and successor. Every host was entrusted not only with the Quirk but also with the duty of using it to stop the evil of All For One. It's currently unknown if every user managed to confront All For One like they were supposed to. Nana Shimura was implied to have been killed by his hands, while her direct apprentice and heir to One For All, Toshinori Yagi, fought All For One at least twice, winning both battles.
The named wielders of One For All so far are only Nana Shimura, the seventh, Toshinori Yagi, the eighth, and Izuku Midoriya, the ninth and current holder. All the previous users of One For All seem to be aware of Izuku being the ninth holder of the Quirk.
All for One's Brother
The first user of One For All was the little brother of a villain who had the Quirk, .
Though small and sickly, he had a strong sense of justice and did not back down from opposing his brother's evil deeds. One For All was formed from the mutation of his innate Quirk, and the Quirk All For One forced upon him. The younger brother attempted to defeat his older brother with his newly merged Quirk (now called One For All), but didn't have the sufficient power to do so.
He then passed One For All down to an unknown successor, in the hopes that someone in the future would eventually stop his evil older brother once and for all, a cycle that continues to this day. Even after his death, the brother is aware of Izuku Midoriya being the ninth wielder of One For All and showed him the events leading to the creation of One For All.
Nana Shimura
Toshinori's predecessor and the seventh successor of One For All.
Little is known about Nana's proficiency with One For All, other than she was not capable to bring down All For One. She mentored a boy named Toshinori Yagi, having transferred One For All to him.
Toshinori Yagi
As world-renowned hero All Might, Toshinori is the eighth owner and a very proficient user of this Quirk.
Throughout his career, Toshinori was regarded as the most powerful hero of all time and remained undefeated. With the goal of being a pillar for society, he put One For All to great use, defeating all sorts of criminals, rescuing countless people from danger and turning himself into a legend.
Toshinori is probably the best-known user of the Quirk, if not one of the most talented. Gran Torino once stated that Toshinori did not take long to adapt to One For All, having been blessed with an extremely resilient body despite being born Quirkless. He was able to control and focus his power into any extremity he chose without recoil.
However, due to an untreatable wound that was inflicted on him by All For One in their first known encounter, he could only utilize his Quirk for three hours straight; any longer and it would strain his body. And if he was forced to employ One For All too much, the time limit for using his Quirk would shorten as a repercussion. After transferring the power to Izuku, his ability to use One For All slowly diminished.
Toshinori summoning One For All's power for the last time.
During his second battle with All For One during the League of Villains' hideout raid, Toshinori completely depleted all the remains of One for All from his body in order to defeat the villain, essentially leaving him Quirkless once again. Although he can still transform for an instant, he cannot maintain his muscle form anymore as it causes great strain on his body, reverting back very quickly. Having retired himself from heroic activity thanks to this, Toshinori now dedicates himself to solely assisting Izuku in mastering the power of One For All so that he may become a great hero of his own.
Izuku Midoriya
Initially, using One For All caused heavy injuries to Izuku's body.
Izuku was chosen by All Might to become the ninth holder of One For All, after the student had proven himself worthy to inherit the Quirk, having done so by ingesting one of All Might's hair strands. Initially, Izuku could only unleash powerful displays of strength at the cost of gravely injuring his own body, as the ten months of training prior to obtaining the Quirk was about getting him to the point of being able to physically hold One For All without blowing off his own limbs. Despite his lack of training or control, One For All's physical backlash was the first step Izuku needed to overcome in mastering this power.
When Izuku manifests One For All's power, his body starts glowing and emitting sparks, with red-colored, vein-like streams coursing throughout his figure. He first used One For All's full power to destroy a giant villain bot in a single punch at the cost of breaking his arm and both his legs.
Izuku manifesting One For All's power into his right arm.
Izuku eventually came up with a way to minimize damage to himself by focusing One For All's power into his fingers individually. Later, he started subconsciously holding back the power of One For All against living beings. From this point on, Izuku began learning on how to properly modulate the output of his Quirk more effectively.
By focusing One For All in certain portions of his body, he can limit the Quirk's power to avoid breaking his bones. He showcased this in both encounters with Shoto Todoroki during the U.A. Sports Festival. He was able to focus One For All into his hand to break Shoto's defense during the Cavalry Battle, and also to punch him a few times during their match in the finals. At that point, All Might believed that Izuku was capable of harnessing only five percent of One For All's power without backlash. Izuku's fight with Shoto proved he was okay with injuring himself as long as he believed he could be healed later on by Recovery Girl. After the conclusion battle, Recovery Girl made it clear that she now refused to heal self-inflicted injuries of that nature, demanding Izuku find a new way to utilize his Quirk.
It is only after training with Gran Torino that Izuku discovers a way to use One For All with no repercussions. During their time together, Gran Torino taught Izuku that his movements and smashes were too slow, as he treated One For All more like a special move than a natural ability. While training himself in an alleyway, Izuku tried regulating his Quirk's power into his legs in order to scale the side of a building. Unfortunately, he discovered that Gran Torino's previous evaluation was correct and failed to do so.
Izuku eventually realized that he was using One For All solely in the limbs that required it, thus severely slowing down his overall reaction time. To compensate, Izuku developed One for All: Full Cowl, which takes advantage of the five percent Izuku can safely work with to increase his strength and agility by letting this small amount of One For All to flow throughout his whole body.
Izuku using One For All: Full Cowl.
Using Full Cowl, Izuku can easily scale the side of buildings, jump large clearings between structures and quickly navigate through cluttered areas. Many of his newfound movements are attributed to watching the way Katsuki Bakugo propels himself using his Explosion Quirk. Izuku could spar close to the speed of Gran Torino and even held his own against Stain in his first real fight. Even so, if Izuku does not remain calm and alert while using his Quirk, he might go over his five percent limit and injure himself.
During the rescue training race, Izuku used his Full Cowl to enhance his speed and agility and was able to outpace his classmates. This display garnered much shock from his classmates and All Might.
Izuku unlocks 8% of One For All during his bout with Katsuki.
In his second fight with Katsuki, Izuku instinctively found out how to wield One For All at eight percent of its full power without repercussions. Izuku can access any percentage of the full power of One For All, however, any higher than his current limit will damage his body as seen in his fight with Overhaul.
While in physical contact with Eri, Izuku was temporarily able to use One For All at 100 percent of its full power with no consequences, due to Eri's Quirk constantly rewinding all of the damage Izuku was doing to his own body.
In his training sessions with All Might around the time of U.A.'s Cultural Festival, Izuku revealed to All Might that he had discovered during the internships he could use 20 percent of One For All for a very short time if in a desperate situation. Any longer than a brief instant would result in harm to his body. Lamenting his "inability" to perform any long-ranged moves in the battle against Overhaul, Izuku was told that he already had the capacity to do so. All Might had planned to wait until his disciple had control of at least 15 percent of One for All to begin teaching him said moves, but seeing that Izuku had learned how to briefly bring out 20 percent of One For All, which was more than enough to manipulate wind pressure, All Might decided to instruct him on how to perform them. After learning the new technique and receiving new equipment from Hatsume to help harness the wind created, Izuku was able to put the super move to the test in his battle against Gentle Criminal.
During the fifth round of the joint training session between Class 1-A and 1-B, dark energy starts to shoot from Izuku's arm that heavily damages his surroundings, and pulls him along against his will. This causes him intense pain and he can't deactivate One For All off in this state.
Quirk: Spikes
Type: Transformative
Info: He is able to make foot long spikes on any part of his body in order to use as piercing weapons.
Quirk: Moister Compression
Type: Emitter
Info: He can compress the moister around him to form orbs of compressed moister, and manipulate them at will.
Quirk: Rock Body
Type: Transformative
Info: He is able to make any form of his body turn into a rock like form of his body, and most likely has the hardness of said rock.
Quirk: Flame Thrower
Type: Emitter
Info: He is able to create flames from the palms of his hands.
Quirk: 4 Arms
Type: Transformative
Info: He is able to create 2 extra arms from his back and use them like any other arm. he can also use Quirks with the 2 extra arms.
Quirk: Sharp Tooth
Type: Transformative
Info: He is able to increase all of his teeth to make them sharper, larger, and thicker.
Quirk: Labial Frenulum Enlargement
Type: Transformative
Info: He can increase the size of his Labial Frenulum as a means of intimidation, or a means to gross out someone.
Quirk: Horn
Type: Transformative
Info: He is able to create two horns from the top of his head about 1 foot long, and use them as possible offensive weapons.
Quirk: Telekinesis
Type: Emitter
Info: He can lift objects with his mind and also throw them at high speeds with accuracy and total deadliness if needed.
Quirk: Top-Half Muscle Enlargement
Type: Transformative
Info: He can Enlarge the whole top-half of his body(except his head). He can use this as a means of strength or show.
Quirk: Wind Manipulation
Type: Emitter
Info: He can manipulate the wind in any way he wants, whether it be blowing people away, simply moving them, or injuring them.
Quirk: Mud-Sludge
Type: Transformative
Info: He can turn his body into a greenish sludgy form, and then use it to go through cracks, and be able to withstand attacks other than from All Might.
Quirk: Shock Absorption
Type: Emitter
Info: This Quirk allows Izuku to absorb the shock caused by physical blows. This ability was specifically given to Nomu in order to counteract All Migh's physical strength, but there is a limit to how much impact this Quirk can absorb. While Nomu hasn't full demonstrated this, it has been noted that shock absorption can also absorb attacks and fire them back like a recoil.
Quirk: Super Regeneration
Type: Emitter
Info: This Quirk has the ability to regenerate any sort of injuries on the user's body, such as missing limbs, at incredible speeds. All For One once stole and tried to use this Quirk to heal himself from the heavy damage All Might caused to him, but because his body had already cicatrized those injuries, the Quirk had no effect and was considered useless.
Quirk: Regeneration
Type: Emitter
Info: This Quirk allows him to heal from wounds such as slicing a part of a persons skin off, or from minor bruises. This Quirk CAN heal him from limb loss, though it is far slower than Super Regeneration.
Quirk: Pterodactyl
Type: Transformative
Info: This Quirk gave strong claws. It can use it's talons for picking up people and objects alike.
Quirk: Absorption and Release
Type: Emitter
Info: The four-eyed Nomu possesses a Quirk that allows it to absorb attacks and then to release them back at its foes, though it still takes damage from the attack.
Quirk: Muscle Enlargement
Type: Transformative
Info: The four-eyed Nomu possesses a Quirk that allows it to enlarge its muscles, increasing its physical capabilities.
Quirk: Tongue Web
Type: Transformative
Info: The four-eyed Nomu possesses a Quirk that allows it to extend its tongue in a web-like formation.
Izuku's Total Number of Quirks: 21