In the fight with Noumu, since Noumu was as strong as All Might, and it was made to battle All Might at 100%, All Might has to punch him with over 100% of his power. And in the last episode of My Hero Academia (Season 3, Episode 4)
Midoriya punchs muscular with One for All 1,000,000%
Does this mean One for All give unlimited power? Or how can they punch with over 100% of their power?
One for All gives unlimited power?
No, it doesn't. You can't just get 101% power, where is the extra 1% coming from? Out of nowhere? Nothing comes out of nothing! By 100% power, it means the power of all the successors of One for All (as far as I understood). Thus again, it is impossible to get unlimited power.
And if you based your question (clearly you did) after watching Midoriya using One for All at 1,000,000%, I would ask you to think of it again. Can Midoriya even use 100% of One for All in his current condition?
Clearly Midoriya can't even use or control 50% of his power (or let's just agree that he can't use his full power yet without arguing on the percentage)
Now it's time to unravel the mystery. How did Midoriya use 1,000,000% of One for All? Without saying a word, I will just post a picture of the Author explaining how he did that:
I'd wager that it all comes down to the risks and consequences of going above 100%. If you look at midoriya, when he uses 100% of One for All, it leaves quite a bit of damages. Wich mean that :
The strength of One For All is not limited by one's body
If your body is able to contain One for All, then nice, you can use it at 100% of power all the time, but if you go over the 100% limit, there's no proof that it won't have an effect on your body.
Let's take the All might vs Noumu fight, if you remember well, after defeating Noumu, All-Might was exhausted, and could'nt gather the strength to throw even one punch. While it is true that all might is wounded, and is time limit is closing in, I think it's safe to assume that going above 100% accelerated his exhaustion.
One for All users are able to control the output of their strength
As shown by Midoriya, it is possible to reduces the output of One for All. That's how Midoriya is able to use it without breaking his body in half : He reduces the power output, wich also reduced the harm to his body.
Now if he is able to reduce the power output, and doing so reduces the harm to his body, then I think it's safe to assume that he can also increase the strength of his output, and doing so would increase the harm on his body.
So, Can One for All grant unlimited power ? Technically yes, but using One for All comes with a price, wich is tied to the power output you use. If you go too far, it could probably kill you.
Deku never uses 100% ever, except in the battle against Muscular. The doctor told Izuku that 80% is everyone's limit, but in an emergency they'll break that limiter and use 100%, but it really hurts the body. Plus, if Deku really had used 1 million percent of One for All's power, it would have killed him and destroyed the whole of Japan.
my answer is one for all cannot be unlimited once someone transfers one for all to another quirkless person but the one who tranfered it to someone will lose one for all if they use their fire to much while the person that got OFA but hasen't tranfered it to her/he will continue on now your probably asking me "what happens with the one who has not tranfered it" well when the person has not transferd this OFA their fire will grow bigger when they use it.
It is not logically true that one for all can grant unlimited power. But deku and all might were able to go beyond because of the adrenaline gushing in their body at the time of crisis. Adrenaline is a hormone which provides super strength for a short period of time in intense situations like that of deku with muscular. There have also been real life incidents regarding adrenaline where people lift up Cars to save their child. This super strength is unknowingly gained due to adrenaline hormone but only for short period. So strength given by adrenaline+one for all 100% is the reason I think which made them go beyond the power which one for all has to offer. One proof is that mr. Aizawa saying a dailogue "This boy is running of pure adrenaline" in eng dub in his inner mind when he meets deku in episode 5 season 3.. And then he says that "The only reason he is able to move with those injuries is due to the endorphin pumping out of his body" Endorphines decreases the pain..therefore deku cannot sense the pain for a short period of time. And then automatically collapses when bakugo is kidnapped after shouting loud in regret. That means both adrenaline and endorphin had stopped working at that time. That's my theory which is believe is to be the reason.
