All For One is the single most powerful antagonist of the My Hero Academia universe. Having collected an uncountable number of quirks for longer than many of the series' heroes have been alive, he was the rightful and undisputed master of the League of Villains.
Despite his fearsome reputation and many quirks, he was nonetheless defeated by All Might, proving that he is not as unbeatable as one might assume. By matching him against the many characters of the Hunter X Hunter universe, we can determine how great the legendary villain's power translates into other anime.
10 Could Beat - Kurapika
Having mastered the ability of "Emperor Time," Kurapika's versatility is his greatest asset. He can borrow from any branch of the Nen family at a whim, giving him the tools necessary to defeat the Phantom Troupe's notorious powerhouse, Uvogin.
Despite the potential at his fingertips, he is limited by the condition that he may only use his scarlet eyes on members of Chrollo's organization. This would be irrelevant against All For One, denying him the essential tools necessary to challenge the villain's untold strength.
9 Would Lose - Meruem
The king of chimera ants, Meruem's physical skills have surpassed All Might's in every perceivable degree. He was able to withstand the unmitigated fury of Isaac Netero, whose statue caused territorial destruction beyond the U.A nomu's wildest dreams (who in turn was nearly responsible for defeating the Symbol of Peace).
Further, he relies more on his raw physical striking power than Nen abilities or "quirks." This entails that All For One would have nothing notable to steal in a melee confrontation and would cost him his head soon after. Not even the criminal mastermind's shock inversion would be capable of fully preventing the king's punishment.
8 Could Beat - Leol
Leol is able to "borrow" the Nen abilities of those who consent in a matter akin to All For One. However, not only is he limited to using a single ability at a time, the skill he had chosen (summoning copious amounts of water) would not be particularly useful against a villain with a breathing apparatus.
Moreover, the criminal could use his long tendrils to drag the lion beneath the waves, where he would then use his staggering physical strength to obliterate the chimera ant for his insolence once his quirk had been stolen.
7 Would Lose - Killua
Killua's "godspeed" renders him one of the fastest characters in the Hunter X Hunter universe and far beyond All For One's ability to anticipate. He is able to move as quickly as lightning, projecting it from his hands to stun enemies and overwhelm them with his intensity.
Further, he can also rip the hearts from his opponents' chests with his razor sharp claws. This gives him the option of electrocuting All For One to death or alternatively to blitz him before he has the chance to seize the assassin and steal his Nen.
6 Could Beat - Knov
A seasoned veteran of the Hunter's Association, Knov has the ability to create portals by which he and his allies might travel. They can be applied in a combat capacity by closing them at a convenient time and decapitating an enemy caught in the gateway.
Knov's downfall comes from his lack of nerve. He cowered at Neferpitou before even glimpsing them, and given the harrowing manner in which All For One was presented, the hunter would face similar fear against the helmeted villain.
5 Would Lose - Morel
Morel's "Deep Purple" enabled him to create many minions from his pipe, assuming any shape of his desire. The clones themselves pose a physical threat to any that cross their path, just as capable of inflicting physical damage as Morel himself.
Though All For One may be able to glimpse him amidst the smoke on account of his enhanced vision, Morel's tireless ability to produce these clones would force the mastermind to fight them until he is exhausted. Since the league's leader has sustained severe injuries after his fateful encounter with All Might, his stamina pales before the hunter's own.
4 Could Beat - Uvogin
Uvogin may possess boundless physical strength similar to All Might's, but there are a number of shortcomings which would allow All For One to defeat him. Not only is the Phantom Troupe member reckless, he does not have a fraction of Meruem's durability, taking damage from Kurapika with simple punches and kicks.
Consequently, this implies he would be vulnerable to All For One's offensives, especially if he channels a number of different quirks to form a grotesque, fleshy fist. After their initial contact, the villain would sap Uvogin's enhancer Nen and most of his physical strength along with it.
3 Would Lose - Razor
One of Ging's closest friends, Razor was a brilliant Nen user who was capable of single handedly expunging the Phantom Troupe from Greed Island. This speaks to his strength and skill, as it is a feat few others of the series can claim.
His offense includes throwing Nen enhanced balls at such a velocity that it was difficult for even Hisoka to dodge them. Should any of them connect, it would crush their head, and given All For One's lacking agility, it's unlikely he could get out of the way before being annihilated.
2 Could Beat - Shizuku
Shizuku's vacuum cleaner had a powerful suction, one which could drain an adversary dry of blood just by creating the tiniest incision on their body. It made her a respected member of the Troupe and a deceptively competent fighter.
Unfortunately for her, All For One could seize the woman with his tendrils, using his vastly superior physical strength to cast her only weapon aside. While his quirk may not be as effective against her since her abilities rely on her gear, he would still be able to snap her neck once she was in his clutches.
1 Would Lose - Netero
Perhaps All For One's greatest asset (even more than his physical strength or number of quirks) is his ability to deprive his enemies of their gifts. The only way he can accomplish this, though, is if he manages to touch their physical body.
Considering that Isaac Netero's fighting prowess is oriented around his gigantic statue, it follows that the villain would never have the chance. Any attempt at pulling the chairman away from his construct would be swatted by a gigantic golden palm before reducing him to a bloody stain on the ground.