My Hero Academia: What Caused All For One's Quirk To Be Broken?

Currently, the My Hero Academia series is entering its final arc where all heroes in Japan are fighting against existing villains, one of which is All For One. 

This is the biggest battle in the series. 

Being the last arc and presenting an epic battle, of course there are many moments that managed to grab the attention of fans. An example is the fight of brother and sister, Dabi and Shoto Todoroki.

In addition, the moment that is no less surprising during this final battle arc is how All For One's arc fails to function. 

The Quirk has been the mainstay of the main villain for decades. 

However, for the first time the Quirk, which AFO had controlled, rebelled. This is something that happens very rarely.

Moreover, the Quirk that AFO has he has since birth. 

This also makes many fans curious as to why this happened, and how the situation arose. 

Unfortunately, All For One itself does not even know the exact answer to this. 

Even so, there is a rather interesting theory where there is a possibility that Kyoka Jiro's Quirk Earphone Jack is the cause.

Jiro So The Cause?

Before Jiro attacked All For One, the villain mocked Jiro for disturbing his view and daring to approach him. This is indeed quite reasonable, considering AFO is the strongest villain in the series. 

Meanwhile, Jiro is not a hero who has tremendous power that can defeat All For One. 

In fact, he didn't have the experience of fighting AFOs like Endeavor or All Might.

All For One really looks down on Jiro's figure, in which he thinks Jiro is not a threat. 

And this was indeed proven when AFO attacked him with a Quirk combination attack. 

However, the situation then changes slightly when Jiro uses the Heartbeat Wall: Legato technique. Initially, AFO again mocked this epic attack from Jiro. 

However, it might be an effect that he wasn't aware of later.

One detail that all geeks might miss, when Jiro attacks the AFO with his Legato technique he really puts all his strength into it. 

Also, this is the first time Jiro has attacked in such a rage. 

Facing a criminal figure who has terrorized his friends in the world really made Jiro frustrated and scared. 

However, he then channeled those emotions into one of his attacks.

After that attack, All For One then realized that the Quirk he had could no longer be used. 

The souls of all the Quirk possessors that he had stolen previously began to fight against the AFO. 

Although there has been no official confirmation, there is speculation that perhaps Jiro's attack is an awakened form of his Quirk.

Or it could be that Jiro actually managed to use the greatest potential of his Quirk that he didn't know existed. 

This is actually not the first time Jiro has displayed such epic power. 

When she sang for grades 1-A, her friends were completely emotional with her singing voice. 

He was able to thrill his friends after the show.

Conclusion

All For One himself later stated that what happened to his Quirk was not something that should have happened. 

This can be realized because of the attitude and determination of the heroes who never give up to be able to face All For One, even though they lost strongly. 

Perhaps, it accidentally coincided with Jiro's attack. 

However, the speculation is quite reasonable.

The power of All For One's Quirk itself has actually started to weaken since he entrusted his Quirk to Shigaraki, and did other duplications. 

This may be the reason why AFO's Quirk is vulnerable to being affected by outside attacks or other people's attacks. 

Jiro's attack has the same effect and power as a Quirk.

That is, it is not impossible if Jiro is one – or even the main cause – of All For One's Quirk malfunction. 

The series itself has shown the same thing before, for example Shinso's Quirk Brainwashing and Hassaikai's Confession Quirk.