Class 1A has the opportunity to square off against Mirio, the top student in the entire school. It seems like a great test of strength, so why didn’t Todoroki fight Mirio?
Todoroki didn’t fight Mirio because he didn’t have a provisional license yet. Aizawa suggests Todoroki can fight anyways, but he still says he’d prefer to have the license first.
It’s likely that a little bit of fear plays into this decision as well. A few panels prior, Todoroki lets out a giant “gulp” sound effect while watching Mirio decimate half his class in the blink of an eye.
Todoroki doesn’t fight Mirio alongside his class
Chapter #123 shows Class 1A squaring off against Mirio. Sensei Aizawa warns the students that Mirio is part of U.A. ‘s “Big 3” and he’s incredibly skilled.
Mirio notes that almost everyone in Class 1A receives their licenses as first years. Since the class appears to be “go-getters,” he suggests everyone fighting him at once.
The entire class stands in preparation, except for Todoroki. Unbeknownst to Class 1A, Mirio’s quirk allows him to travel through physical objects with ease and reappear through different parts of the floor.
He makes quick work of all the long-range fighters, appearing right in front of them with lightning fast speed. Mirio stands before the melee fighters, looking to challenge them next.
The following chapter, Todoroki is shown standing next to Aizawa. He’s amazed that Mirio took down half of his class in the blink of an eye. Todoroki admits that it makes sense he would be the closest to the top hero spot.
“Not gonna try your own luck,” Aizawa asks Todoroki. “There’s no way you’re not interested in being number one.”
Todoroki replies that he didn’t even receive his provisional license. This could be a valid excuse, but it’s also worth noting that Todoroki let out a giant “gulp” sound effect while watching Mirio fight. It’s likely a little bit of fear also plays into the decision. Todoroki ends up recieving his provisional license later, which involves dealing with a group of elementary schoolers who call him “five weenies.”
So that’s the answer. Todoroki didn’t fight Mirio because he doesn’t have his provisional license. Aizawa says that Todoroki can fight anyways, but he says he doesn’t want to without his license.