Spoiler Warning: This piece contains spoilers for My Hero Academia Season 7.
One For All is a special quirk. Originally possessed by Yoichi Shigaraki, the quirk had no functional use in its original form. Only due to the unwitting intervention of Yoichi’s brother, the villainous All For One, does it get the chance to become the powerhouse ability fans of My Hero Academia know today. With the coming battle promising to end the conflict that began so many years ago between Yoichi and his brother, we decided it was time to take a deep dive into the legendary quirk, its history, the powers it has come to accumulate, and what role it will play in the coming battle.
How Did One For All Get From Yoichi to Midoriya?
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Believed to be quirkless, Yoichi was a sickly man who vehemently opposed how his brother used his quirk to control and manipulate people. Frustrated with his brother’s defiance of his goals, All For One forced his brother to take on a power stockpiling quirk. Rather than feeling gratitude for his brother’s “gift,” Yuichi continued to oppose him. Unbeknownst to either of them, the stockpiling quirk fused with a previously unknown quirk Yoichi had possessed. A quirk that allowed him to pass on other quirks. This fusion marks the birth of the quirk One For All. Unfortunately, Yoichi would die, not knowing what this new power would become.
It wasn’t until Yoichi was slain attempting to escape from All For One that suspicions began to form about what the quirk was. When All For One killed Yoichi, some of his blood splattered on his fleeing ally, Kudo. Shortly after the event, Kudo began feeling strange. After an examination, it was found that his body had taken on a second quirk factor. Kudo became convinced that this quirk was Yoichi’s will lingering in the world. Meanwhile, after attempting to reclaim Yoichi’s quirks from a severed hand he had kept, All For One discovered the quirks were missing and also concluded that Yoichi was still out there. All For One subsequently made it his mission to reclaim his brother, viewing him as his possession.
As the years passed, each bearer of One For All strived to increase the quirk’s power before All For One could come to claim it. Each time All For One tracked down the user of his brother’s quirk, he would find it passed on before his arrival. Kudo passed it on to his ally Bruce. Bruce passed it on to Hikage, who spent his time with One For All hidden in training and would die young. While he believed this was due to a mysterious illness, it would be later revealed that One For All takes a tremendous toll on the body. It dramatically shortens the life of someone if they possess both One For All and another quirk.
The next two holders of One For All, Diagoro and En, barely managed to avoid having the quirk stolen by the relentless All For One. Before En met his fate, he passed it on to the seventh holder, Nana Shimura. Unlike her forebearers, Nana would take a more structured approach to cultivating One For All. She would pick a chosen successor. She would train and prepare her successor for the burden of bearing One For All and the responsibility of stopping All For One. Her choice was a quirkless young man named Toshinori Yagi. Along with the help of her trusted ally Gran Torino, she would help guide this hopeful young man, being instrumental in his transformation into the number one hero, All Might, the Symbol of Peace.
The most visible holder of One For All, All Might, manages to confront All For One and defeat him. This victory comes at a heavy cost as All Might is gravely wounded in the fight, causing his stamina to suffer greatly and reducing how much time he can spend powered up. In the waning days of his strength, All Might was approached by the young man Izuku Midoriya. As someone without a quirk who idolized All Might and wished to follow in his footsteps, Midoriya asked his hero if he could become like him despite not having a quirk. While All Might initially tells the boy no, after witnessing Midorya struggle to save his classmate Bakugo from a villain, All Might decides that Mirodiya’s spirit would make him a worthy holder of One For All and gifts him the quirk.
Much has changed during Midoriya’s stewardship of One For All. While the quirk has always bestowed the bearer with unbelievable strength that has grown with each holder, Midoriya finds himself gaining even more from the quirk. During a moment of stress, while participating in a school competition, Midoriya gains the ability to access the quirks of past holders. This new evolution for the quirk gives Midoriya a whole new arsenal of tools against All For One and his recently chosen heir, Tomura Shigaraki.
While these new abilities greatly enhance Midoriya’s combat abilities, his access to the vestige world is even more important. In a sort of mental plane, Midoriya can commune with the past holders of All For One. Sharing their knowledge of the past and their experiences dealing with All For One proves to be a great boon for the young hero. This ability to plan with his predecessors proves invaluable as the final battle with Shigaraki plays out.
Detecting a weakness in Shigarrki’s core opened up by the Hero Star and Stripe’s final battle with him, the decision is made to intentionally transfer All For One to Shigaraki so the presence of the quirk can weaken his will. After the quirk departs Midoriya, he is left with only embers of the power of All For One—Embers he uses to win the final fight against Shigaraki.
What Are One For All’s Powers?
The core traits of One For All are the ability to stockpile power, which makes the quirk grow stronger with each user, and the ability to pass the quirk onto another holder. Until Midoriya inherited the quirk, these were the holder’s only abilities gained from One For All. That has changed recently, as the previous holders’ quirks have also manifested, allowing their powers to augment Midoriya’s arsenal. These powers are:
Float: Originally wielded by the seventh holder, this quirk allows the user to levitate.
Blackwhip: This quirk belongs to the fifth holder and allows the user to extend black tendrils from their body, which can be used to restrain enemies and improve locomotion.
Gearshift: The second holder’s quirk, this ability allows the user to alter the speed of anything they touch. This allows them to increase the speed of their attacks or cause enemies to lose control of their own velocity.
Danger Sense: This is from the fourth holder. It grants the user an early warning when threats are approaching.
Smokescreen: Gained from the sixth older, smokescreen allows the user to create thick clouds of purple smoke that can obscure vision.
Fa Jin: The third holder’s quirk allows the user to build up and store kinetic energy through repetitive motion. Once charged, the energy can be released to create an explosive burst of speed or power.
The final element of One For All’s power is its resistance to being stolen. Because it is born from the combined willpower of the holders, One For All cannot be forcibly taken by normal means. Only with extreme determination or an erosion of the will of the holders can the quirk be removed piece by piece.
With so much raw power at its disposal, it is clear why One For All is arguably the most impactful quirk in My Hero Academia. It stands at the center of the plot, allowing the heroes their best chance at stopping the villains from succeeding in their nefarious schemes.
