For those who don't know a brief description of the 2 major quirks involved in the main story of My Hero Academia are the quirks One for All (All Might, Izuku) and All for One.

First, about One for All,

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. One For All allows the user to access stockpiled power, which grants the user momentary superhuman strength at destructive levels, increased agility, and superhuman speed. Izuku Midoriya is the ninth user of One for All.

Now, about All for One,

All For One allows the user to steal other people's Quirks and wield these stolen powers as their own. All For One also allows the user to transfer stolen Quirks to other people. The user of All For One can combine several Quirks in order to create devastating techniques which would normally not be possible with the usage of only one Quirk.

In the fight between All Might and All for one,

we see the combined effects of multiple quirks used together by All for one. Going by the name that is around 10-12 stolen offensive quirks (not to mention numerous defensive ones as well as ones allowing him to live etc.

How is it that the combined physical prowess of 9 individuals (2 of which we know were quirkless) can be stronger than the combination of at least a dozen Strong quirks, maybe more?

Possibly Related: What does it mean that "One for All" allows to stockpile power? The accepted answer fails to explain how this stockpiling would outgrow All for One unless it's some sort of exponential increase for One for All vs a linear increase for All for One.

  • May be he inherited the power of a super strong user? I dont think it was never explained anyway.
    – Pablo
    Apr 21, 2018 at 1:55
  • There's a lot we don't know about that. All Might is the seventh or eight user of One For All. There might have been a super powerful user of that quirk. Or, even your point may be true that power keeps on increasing exponentially. There's too much unknown to answer that. Apr 21, 2018 at 2:57
  • or a linear increase in One for All vs an asymptotic increase for all for one May 30, 2018 at 22:45

5 Answers 5


Because All for One is adding powers on top of one another, while One for All is multiplicating its strength.

All for One is using the quirks of other users, I think he isn't the kind of person to go and master each and every one of those quirks.

On the other hand, every user of One for All has been training the same quirk again and again, mastering it, and then passing their knowledge to their successors.

I don't think the battle All for One vs One for All was a pure contest of strength, but also of mastery and technique. You can clearly see that when it comes to pure strength, All for One is stronger. But when it comes to ability, All Might was better.

What made All Might victorious was not his strength, but his ability to think ahead, and his near-perfect mastery of One for All.

  • 1
    Do you have a reference for this?
    – SK19
    May 13, 2018 at 18:29
  • For someone who is well informed about the series, this answer is very conclusive. May 30, 2018 at 15:52

There's no reason to assume that the strength of AFO's techniques is a simple function of the number of quirks that he incorporates.

Think of it like a recipe. Does a dish always get better and better as you add more and more ingredients? The answer is no. It only gets better if you add the right combinations of ingredients, and even then, there comes a point where adding more ingredients serves no purpose. Sometimes adding unneeded ingredients even makes the dish worse.

Meanwhile, OFA does just keep getting stronger. It doesn't necessarily have to worry about coherently engineering a bunch of different synergies. Not that it doesn't have other limitations, but apparently they're not severe enough to prevent it from being able to overpower AFO.

Another point is that there are physical limits to how. An example was how Todoroki's body temperature dropped during his fight with Deku in the tournament. It is possible that AFO has similar limits.

It need not be a contrived limit either such as some sort of "maximum" number of quirks he can marshal at once. It could be the case that he just doesn't have the mental capacity to keep track of all of the quirks he can possibly use at once.


One for All may be stronger because of the exponential increases, but certain quirk combinations of All for One are just too good to be ignored.

For example, the intelligence quirk of the principle would allow him the intelligence required to use all sorts of quirks to their fullest potential. For example, the intelligence quirk combined with foresight and the create quirk would allow All for One the ability to counter any opponent he fights.

One for All may have more strength, but All for One has almost infinite flexibility with any quirk combinations at his fingertips. He has the power to counter any opponent.

Another quirk combination that could completely shut down any opponent without interacting with them in any way would be Eraser Head's quirk to stop any shenanigans, brainwashing, and confession.


If memory serves, it was stated (or at least heavily implied) that the increase of One for All is exponential. Whereas All for One is only increasing linearly very fast, but it was most likely overtaken or at least matched in power by the fight against All Might.

It is also likely that All for One is experiencing Logarithmic growth causing his power increase to slow down as he reaches his mental/physical limit for the usage of quirks.


I don't think it's clear that All Might didn't have a quirk prior to receiving All For One. He said he didn't have a quirk ... but everything else indicates he did. For instance, when he can't use his quirk, his body shrinks and loses all the mass he has as All Might. This implies that ability is a quirk. I believe All Might actually had a quirk that, just like the original user of All For One was not evident until it was combined with the other quirk.

What isn't clear also is why Deku has not shown a significant mass increase as well, especially when he is using 100% of the power of his quirk. Admittedly in the anime, he is only using about 8% as of season 3's ending. So this may change as he is able to use more of All For One.

  • It's already clear that all might didn't had a quirk before receiving One for All. Go back to reading manga. The reason why All might was inflating again and again is because he had an injury which makes him lose power when using one for all, thus he can only work 3 hours a day. But when All might transferred his quirk to deku, one for all only left a remnant of it to all might so that he could use it atleast just once more. Mar 13, 2021 at 14:10
  • Plus, if all might had a quirk, he would have already died in 30 years old because when you already have a quirk, one for all will combine with that quirk in exchange for not being able to use the full potential of one for all and less life force than a normal human. It doesn't mean having a quirk with one for all will make you stronger, it means that it will only combine with it so that the current one for all user can use your quirk, too. So therefore, all might doesn't have a quirk. If so, he would've been ded already. Mar 13, 2021 at 14:10

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