All Might is the strongest known Hero in the world of My Hero Academia and the man who was once known to be Japan's Symbol of Peace. He held the powers of One For All, a Quirk passed down to him from his master, Nana Shimura. In terms of power, All Might was unmatched right until the very end of his Hero career.
In his prime, he was said to be much stronger than he was throughout most of the story and only a few could put up a fight against him. Here are 5 characters prime All Might could easily defeat and 5 others who could put up a fight against him.
10 Could Defeat Easily: USJ Nomu
All Might traded blows with the USJ Nomu in the first season of My Hero Academia and struggled quite a bit against him. This was mostly because the Nomu was created to take on All Might at his 100%.
Despite that, All Might managed to push beyond all his limits and defeat him. Just as he declared himself, in his prime, he would've defeated the Nomu with just three punches.
9 Put Up A Fight: Endeavor
Endeavor was once the Number 2 Hero, always in All Might's shadow. After All Might's retirement, Endeavor stepped up and became much stronger after realizing what it truly meant to be the Symbol of Peace.
Like All Might, Endeavor is capable of pushing beyond his limits, as seen during his fight against Hood. Although he'd lose to All Might, he'd have put up a great fight against him.
8 Could Defeat Easily: Hawks
Hawks, the Wing Hero, is the current Number 2 in My Hero Academia. Along with having tremendous strength, he also has great agility and a sharp intellect which helps him in most battles.
Hawks mostly relies on his speed in fights, however, All Might is both stronger and faster than him. In his prime, All Might would've defeated Hawks within seconds.
7 Put Up A Fight: All For One
All For One is the strongest known Villain in the world of My Hero Academia to date. Known to be the only person to put up a proper fight against All Might, he could easily match him in battle thanks to his Quirk.
When the two clashed in Kamino, All For One managed to push All Might beyond his 100%. Although his chances of beating the Symbol of Peace are quite low, he'd definitely put up a great fight against him.
6 Could Defeat Easily: Dabi
Dabi is one of the members of the League of Villains, now known as the Paranormal Liberation Front. He possesses the powers of an unnamed Quirk that lets him produce blue flames and burn his targets to a crisp.
Dabi, although strong, is absolutely no match for All Might. In his prime, All Might would probably take out Dabi with a single hit. In fact, All Might would not even need half his power to defeat Dabi in a fight.
5 Put Up A Fight: Nine
Nine was the main antagonist of My Hero Academia: Heroes Rising. He was known to be a criminal with powers on par with that of All For One, if not greater. Nine had the power to use multiple Quirks just like All For One, which made him a tremendous threat to anyone.
Whether All Might would've been able to defeat him or not is something that'll be up in the air forever, however, Nine would certainly put up a great fight against him.
4 Could Defeat Easily: Rikiya Yotsubashi
Rikiya Yotsubashi, also known as Re-Destro, was once the leader of the Meta Liberation Army. He is quite a powerful character who was strong enough to overpower Shigaraki Tomura in battle (prior to his Quirk awakening).
Rikiya has the power of Stress which lets him convert all his tension into raw power. He's strong enough to wipe out cities at full power, however, despite that, All Might would be able to deal with him without any trouble in his prime.
3 Put Up A Fight: Shigaraki Tomura
Shigaraki Tomura is the strongest known character in My Hero Academia currently, having awakened his Decay Quirk and gained access to All For One through a surgery.
He appears to be an unstoppable force and his strength cannot be matched by any active Hero right now. In his prime, All Might could possibly be able to defeat him, however, his chances are falling to Shigaraki aren't low either. Either way, Tomura would put up a great fight against him.
2 Could Defeat Easily: Overhaul
Overhaul is among the strongest characters in My Hero Academia and he was one of the major antagonists in the fourth season of the series. With the power of the Overhaul Quirk at his side, he could kill anyone with just a single touch of his palm.
However, he had quite a tough time while fighting Mirio Togata, which is a clear indication that All Might would defeat him within seconds, especially in his prime.
1 Put Up A Fight: Izuku Midoriya (100% One For All)
At 100% One For All, Izuku Midoriya becomes a menace for anyone fighting him. With this power, he was able to defeat Overhaul quite easily. Although it'll take Izuku quite some time to work up his skill to 100%, once he does, he'll be comparable to All Might.
Whether he'll be able to surpass him or not remains to be seen but it goes without saying that at his full power, Izuku would definitely put up a fight against All Might in his prime.