Superhero powers are often a bit hard to understand upfront. After the age of Superman, powers tended to get more complex, expanding in scope and detail. The X-Men stories, in particular, have gotten ever increasingly more complicated as stories have grown. Anime is not immune to this either, with series like JoJo's Bizarre Adventure creating ever more complex circumstances for abilities to work. The straightforwardness of Dragon Ball has become a lot harder to find. While the practice of escalation in this way is confusing, it is often pretty fun. It's hard to explain how Satoru Gojo's powers work, but they're always a spectacle to behold. However, confusion is often the biggest issue when it comes to getting into a series.
My Hero Academia actually starts pretty simply—blond boy makes an explosion, protagonist's bones explode while he tries to get stronger, etc. But as the series marched along, the powers got more complicated. From Stain's complicated blood-type paralysis Quirk to La Brava's vague ability to power up her beloved, tons of abilities need a lot of description to make any sense. One power that is a bit more difficult to describe is also one of the most plot-crucial: One For All. This Quirk needs at least a little bit of explanation.
One For All Started Simple to Understand
To talk about how transferring Quirks works, a person first needs to understand the complex backstory of One For All. This Quirk became the legacy of Yoichi Shigaraki. His brother, All For One, initially thought that his younger brother was Quirkless and, using his own Quirk, gave him a Quirk that was made for stockpiling. However, Yoichi did actually have a Quirk, but its only power is that it could be passed along to someone else. The transferring Quirk and the stockpiling Quirk ended up merging to create the Quirk that would be known as All For One. Both brothers offer different versions of transferring Quirks that work in incredibly different ways. Understanding those differences is the key to understanding the concept as a whole.
The Quirk All For One allows the user to steal any Quirk from any person they come into contact with. They can then choose to keep the Quirk or to pass it along to someone else. All For One (the person) demonstrates this quite often throughout the franchise as he takes in multiple Quirks and doles them out to his followers. He even does this to Shigaraki Tomura in his attempts to take over his body and turn him into his successor. Except for One For All, there doesn't seem to be much of a limitation on All For One's ability to steal and re-purpose Quirks. However, there are side effects for bodies that aren't adapted to certain Quirks, and they can often have a harder time dealing with those Quirks. There is also a chance for Quirks to blend and combine. All For One himself is seen doing this in his own fights.
One For All, conversely, is a Quirk that can only move itself and only with the express consent of someone who possesses it. All Might has to agree to pass along the Quirk to Deku before offering his hair to be eaten to complete the transfer. This also prevents it from being stolen—for the most part, anyway. A person can't just commit a stray act of cannibalism to obtain it. The Quirk also comes to merge with other Quirks and each user of One For All makes the Quirk stronger by comparison. For example, Bruce's natural Quirk, Fa Jin, allows for the build-up of kinetic energy for future One For All users to show signs of super strength. There is a period of adjustment for the Quirk, however, and no one inherits it at full strength. The users slowly grow into the Quirk, so keeping the body trained is important. All Might lost a lot of access to the powers of the Quirk after losing multiple organs.
The biggest downside to One For All is that it can shorten the life span of its users. Just like a body can not be built for a transferred Quirk, a body cannot handle all that raw power at once. The fourth user of the Quirk died at age forty and that was considered "old age." It's akin to adding more water to an already full cup, which is why passing it to someone who is Quirkless is ideal. This would liken them to an already empty cup just being filled, like Deku. After transferring the Quirk, the user has some leftover access to the ability, sort of like the smoldering embers after a fire is put out. Eventually, this will run out and never be replenished. There is a phrase in gaming, high-risk-high-reward play style, and this would be an incredibly accurate way to explain this Quirk. The transference aspect of it is so important to its foundation, but it also makes everything a little more dangerous with each generation.
What Are The Consequences of Using All For One and One For All?
Both One For All and All For One are incredibly powerful Quirks in their own right, but the modern One For All would not exist if not for its similar Quirk. All For One was the catalyst for One For All's creation, and it created the greatest challenge that the user would ever face. The act of transferring Quirks doesn't happen without other things happening. As a result, it acts almost like a Jenga tower depending on what the Quirk is and who, exactly, is receiving it. There are a lot of different factors that determine whether a person can even survive having a Quirk transferred into them at all.
Opposite to One For All, All For One does better at transferring Quirks into people who either have them or have had them. There is a not insignificant chance that the person's mind and body will be ruined. A body that has already had a Quirk is a little more ready to receive one than one that hasn't, but that doesn't guarantee survival. People like Spinner are shown to become nearly mindless and violent after being bestowed with Quirks. Two were given to him, and they basically made him into a monster. Even if a person can handle the initial transfer, that doesn't mean it will work out. Aoyama's Navel Laser doesn't agree with his body at all; he needs a piece of support gear to use it, or he gets terrible stomach aches.
Quirk transferring in some way, shape, or form is one of the most important abilities in the entirety of My Hero Academia. It set up the entire plot for the most part and actually worked to shape the entire world of the series itself. It is both the most simple and complex Quirk in the show, and its owners are also simple yet complicated people. All Might and All For One are both two sides of the coin of Quirk transferring. It can take a little work to understand it—something that All Might himself worked on for ages with his own research—and more discoveries are frequently made about its depths in the universe. Taking the time to understand it can only help with a fan's appreciation of the show. Studying up on One For All and All For One may take a lot of effort, but it is a great opportunity for fans to go Plus Ultra.
