WARNING: The following article contains spoilers for the My Hero Academia episode "Unrivaled," streaming now.
With the conclusion of Season 3, the English release of My Hero Academia has caught up to the Japanese. That ending teases a lot of what will happen in Season 4, concluding on what is essentially an introduction to the conflicts that will take place when the series returns. While the prior two seasons of My Hero Academia ended with a climactic battle of some sort, this one ends with a demonstration of power. Class 1-A's final battle of the third season was a friendly match as part of a lesson, meaning there's no real ill-will regardless of the outcome. However, what's remarkable is that Class 1-A lost to a single person: Mirio Togata.
The Big 3 Meet
The Big 3 are the three greatest students at U.A: Mirio Togata, Tamaki Amajiki and Nejire Hado. These three actually appeared earlier in the series, with Midoriya seeing Togata's face sticking out of the floor. However, Midoriya recalls seeing Togata even earlier at the Sports Festival (the same one where Midoriya fought Todoroki and Bakugo ranked first). As for the other two, Amajiki is a scary looking guy with awful stage fright. Hado, on the other hand, is a child-like, over-excited student who asks rapid-fire questions too quickly for anyone to ever respond.
The trio are there to discuss the Hero Work Studies -- a new internship alluded to in the prior episode. However, all of the Big 3 are so socially awkward and unusual that little of what they say actually communicates their points. So Togata decides to communicate in the language he knows best: battle. So he challenges all of Class 1-A to a fight.
All of Class 1-A, except Todoroki and Bakugo who must stay behind as they have yet to earn their Provisional Licenses, show up to the gym to fight Togata. While there is some internal debate as to if any of this competition is necessary, Togata continues all the same.
The first to step up is Midoriya, and, soon, the rest of Class 1-A rallies behind him. The close-combat students try to surround Togata while the more long-range fighters attack from the rear, each student utilizing a strategy that works best for them in order to combat Togata. However, all that proves fruitless when Togata reveals his quirk: Permeation, the ability to phase through matter. Thanks to this, he manages to avoid any damage, weaving to each student to subdue them in short succession. While Midoriya predicts Togata's movement, it proves ineffective, since Togata just phases through Midoriya's body when he attempts to deliver a finishing kick.
Togata decimates the entire class.
The Value of Hard Work
Aizawa, the teacher of Class 1-A, confirms privately to Todoroki that Togata isn't just the best student in the school. He's one of the greatest heroes around, ranked alongside Endeavor and All Might in terms of sheer power. However, as Togata acknowledges, his quirk is fairly weak on its own. He's only as powerful as he is thanks to his incredible training and hard work.
Togata explains that, when his Quirk is active, he loses his senses. Everything passes through his body, including touch, light, audio, smells -- everything. He had to train excessively to utilize his Quirk despite his huge weakness. Togata learned this, in many ways, thanks to the Hero Work Studies classes.
He assures the younger students that this internship, unlike his prior internship, will push them to being like sidekicks to real heroes, which will force them to use their powers in incredibly dangerous scenarios. But in the end, all that hard work will make them even stronger.
What Will Come in Season 4
The end of the episode sets up several plot threads that will play into Season 4. Todoroki, observing all that happened from afar, fears he may be falling behind thanks to him failing to earn his license. The Big 3 speculate if any of Class 1-A is particularly noteworthy, which results in Togata proposing Midoriya work with a hero he refers to as "Sir."
Midoriya contacts Gran Torino, who he interned under previously, to see about a placement for Hero Work Studies. Gran Torino, however, declines. He's preoccupied tracking down the League of Villains with the police. And this leads to the final cliffhanger of Season 3. Twice brings Overhaul, the villain introduced in the prior episode, to interview for the League of Villains. The stage is set for the villains to reshape society into their image. Next season, the League will bring real chaos to the order of the world -- which is now without All Might. The world is in need of a great hero.