AN: Don't get me wrong everybody, I really do like Aizawa as he is now, but he was a friggin asshole in the beginning and that first day of classes always pissed me off, as well as the backstory for Aizawa they gave. So, I made this short piece, have fun everyone!

How are you a teacher?

-Izuku-

Letting out a breath, Izuku stared ahead as he got ready for the fifty-meter dash. At his side, Kacchan was glaring at him, palms crackling as the explosion quirk user got ready to blast forward. Focusing, Izuku called upon the power of One for All, spreading it out through his body. Miraculously, having shattered his arm and both legs had been a good motivator for getting a grip on his power and asking All Might for advice. Focused, Izuku waited for Iida to fire the pistol into the air to mark the beginning of their sprint while Aizawa-Sensei observed with the timer and a clipboard to record their times. The moment the gun went off though, he felt his quirk leave him as Kacchan blasted off, covering Izuku with smoke and burning his arms by the passing explosions.

Straightening, he turned towards the sensei who was glaring at him, eyes glowing red with his hair floating ominously. Behind the man, the other students of Class 1A looked nervous, glancing between Izuku himself and the man obviously using a quirk. "I erased your quirk." Aizawa snarled, his capture scarf moving through the air like it was alive "The Judges for the entrance exam…were not rational enough. Someone like you should never be allowed to enroll at this school. You're not ready and have no control over your power. Were you planning to just break your bones again, counting on someone else to save your useless body?"

"No, I-" Izuku began talking only for the capture scarf to grab him and pull him close to the still glaring man.

"No matter what your intentions are, you'd be nothing more than a-" he was cut off with a grunt of pain as Izuku drove a knee into his balls.

"Watch it Sensei." Izuku snapped, now thoroughly pissed off and through of everyone looking down on him, "Especially when someone like you shouldn't be a teacher at all." You could hear a pin drop from the various classmates watching.

"Y-you just attacked our teacher!" A tall girl with black hair, he was pretty sure her name was Yayorozu, stammered out in shock.

"The man grabbed me and pulled me against him, it was that or scream for an actual adult." Izuku deadpanned at them while Aizawa got to his feet, still clutching his injured testicles. Not giving him a chance to intervene again, Izuku charged up One for All and shot through the dash length in a blur, his speed comparable to Iida's and no signs of any broken bones. "I didn't like my bones breaking in that entrance exam," Izuku zoomed back over and stared down at the surprised pro "so I took it as incentive. I worked on getting a better grip of my powers and found pros to ask advice for. My quirk manifested late, so I didn't have a lot of time to learn before that test happened. But you, there's no excuse I can see for your actions besides you being a failure as a teacher."

"Midoriya, what are you-" Iida began before Izuku held up a hand to cut him off.

"I did some digging you know," he met Aizawa's gaze as the vampire like man glared "about what pro's might be my homeroom teacher. This one here has a track record for expelling students. Last year he expelled his entire class on the first day. His excuse, 'they didn't have enough potential'." Everyone started muttering at that, the Yayorozu girl looking stunned and commenting that she had been sure the expulsion threat was a bluff. "That's proof he doesn't deserve his job here."

"They didn't have potential, just as you don't." Aizawa glared "You show the same reckless drive of another hero. You showed how illogical you were in the entrance exam, nearly dying to throw a single punch. Getting one trick is not the same as having control over your quirk."

"It's proof you don't actually give a damn about teaching." Izuku shot back, "Plus what you've done earlier. You said we should just leave for trying to make friends? Part of being a Hero is inspiring Hope in others, having charisma and calming others. Knowing how to make friends and be friendly is part of that. You clearly intended to erase my quirk the second I tried using it meaning you wanted to fail and expel me going in, you had no intention of teaching me. Plus, you expelled an entire class. This is a school! We're here to learn how to be Heroes. Expelling so many so easily for not meeting your 'standards' despite the school feeling they warranted education shows you don't actually care about teaching. You're just lazy and want people you think are a decent way to becoming heroes already. Oh, and if you have any thoughts of going ahead and expelling me, I took precautions against that."

"What are you talking about?" Aizawa narrowed his eyes while Izuku's classmates all looked confused.

"Oh, when I found out about your attitude and habits, including the one where you apparently tend to skip the orientation which is supposed to be mandatory, I contacted Principal Nezu about how I expected this to go and invited him to watch. He agreed that if you're just going to expel entire classes you don't seem to have as much interest in actually teaching heroes so he promised me that you can't expel anyone without his permission anymore, and that each student gets to defend themselves against said action. Now come on, I have more tests to do." Walking back to the others, Izuku smirked, amused at the fact that even Kacchan was too stunned to say anything after his little display.

-Nezu-

Happily sipping his tea, Nezu waited for Aizawa to show up the moment classes ended. Sure enough, the door flew open as the grumpy caterpillar of the U.A. staff stalked in, "I wish to have one Izuku Midoriya expelled."

"Denied." Nezu smiled happily, "I'm quite impressed with him, and can't wait to see how far he'll come when someone takes the time to actually be a teacher and show the students how to be heroes." As Aizawa stomped off, Nezu cackled, loving the entertainment All Might's successor was bringing him.