Warning: Spoilers for My Hero Academia, Season 6, Episode 12After fifty episodes of being Quirkless, one of My Hero Academia's most popular heroes has done the impossible and regained his power. In a perfect example of things coming full circle, the very person he sacrificed it for was the one who brought it back.
Mirio Togata, also known by his hero name Lemillion, was a member of UA's "Big Three" and worked with Deku under Sir Nighteye during the Shie Hassaikai arc. Mririo's Quirk was known as Permeation in My Hero Academia, and allowed him to phase through objects, walls, and floors as if they weren't there. During the rescue of Eri from the Shie Hassaikai, Mirio was forced to take a bullet to protect Eri--and in a twist of fate, it was a Quirk-deleting bullet that was created using her own powers. Mirio lost his powers there but continued to defend Eri until Deku arrived. From that point on, Mirio has had to sit on the bench, unable to operate as a hero without a Quirk.
In the episode, entitled "Threads of Hope," Mirio reappears on the battlefield using his Quirk at the last moment, showing up not long after Best Jeanist made his appearance. Mirio reveals via flashback that Eri had been training to gain more control over her Rewind Quirk, having used it on small animals like lizards, repairing their tails when they fell off. Eri revealed that she was trying so hard to master her ability because she wanted to use it to restore Mirio's Quirk in My Hero Academia, rewinding him to a time when he still had it. This wasn't a risk-free procedure, though; if Eri lost control of her Quirk again, Mirio could end up being rewound to a point before he existed, effectively killing him.
Mirio's Triumphant Return
Despite knowing the risks, it seems that Mirio was willing to allow Eri to use her Quirk on him, likely because he knew just how bad the situation that the other heroes were in had gotten. Taking a risk like that just for the chance to head off into another very risky and dangerous scenario is the true mark of a hero, and it's easy to see why Mirio was a contender for One for All before Midoriya showed up. With Endeavor, Bakugo, and Deku all in bad shape, and Todoroki busy fighting his newly-revealed brother Dabi, the heroes were certainly in a tight spot--one that could easily have ended in failure if it weren't for the sudden arrival of Best Jeanist and Lemillion.
Still, it's important to recognize the bravery of young Eri here as well. Eri was terrified of her own power, and had basically no or counseling on how to control it, since the bad guys nabbed her so quickly. In just six months under Aizawa's care, Eri has come far enough to not only be able to use her Quirk deliberately, but to control it enough to achieve a particular goal. It seems Aizawa has taught Eri a thing or two about doing what has to be done.
With My Hero Academia's Mirio back in action, the situation for the heroes has improved dramatically, and no doubt fans around the world were cheering for his return. The battle isn't over quite yet, however, so Mirio must continue to give it his all until the League of Villains are finally defeated.
