If anyone has read past the first war arc and has caught up with the second war, we have all witnessed Mirio’s return with the help from Eri.

With Shigaraki and One For All being the overwhelming villains of the second war, I highly doubt Deku can sustain an equal fighting grounds with both of them. I have a theory that Endeavor will most definitely lose to One For All and thus leaving the burden to Midoriya.

Now, leading to the last option. One For All mentioned that his triumph card is Eri’s syrum that was exploited through Chisaki. I have a feeling that All Might will have to use Eri’s powers to get his powers back, whether that would be temporary.

Nighteye mentioned that he foresaw his death because he would always push himself in dire situations. Which leads to the final battle, One For All (All Might and Deku past predecessors) vs All For One (AFO and Shigaraki).