'Another batch of students.' Aizawa thinks as he waits for his class to arrive at the culling grounds, I mean the training field. '21 this year, why did Nezu drop an extra on me. I'm expelling one today.'
He was going to get a normal class, but at the last minute one of Nezu's friends brought up that the unique quirk group, the Crimson Demons, wanted to join normal society by sending their best to UA. Aizawa strongly voted against just letting them in, but All Might preached inclusiveness and equality at them and everyone else fell for it.
"Don't be so pessimistic Aizawa" All Might had said. "It will be a good experience for the students." He said.
'What a load of nonsense' Aizawa thinks as he watches his student arrive, 'I have enough problems with this limb breaking moron, Endeavors child and several students with dubious disciplinary histories. Now I have this eye-patch wearing chunibyo.'
"Good, you all made it in time." Aizawa begins. "We're doing a traditional fitness test, except with your quirks. Bakugo, come forward."
The boy walks up sneering.
"You scored the highest on the entrance exam." Aizawa begins. 'Without any rescue points, what a hassle.'
"Of course I did!" Bakugo says mistaking his teacher's silence as a need for confirmation.
"Go into that circle and toss this ball as far as you can. Anything goes as long as you stay in the circle."
"Really?" Bakugo says.
"Did I stutter?" Aizawa says, annoyed.
Cackling with glee Bakugo walks to the circle and launches the ball with a shout of 'die.'
The class grew excited both at Bakugo's score and the prospect of free quirk use.
'How annoying' Aizawa thinks, "Exciting? Fun? This is the hero course. I expect all of you to give it your all."
'They still don't seem to be taking it seriously' Aizawa thinks. "The lowest scorer will be expelled."
That got their attention at last. After dealing with some complaints Aizawa started them off on the 50 meter dash.
'Bone breaker hasn't damaged himself yet, and the Crimson Demon is unimpressive.' Aizawa thinks as the class moves to the grip strength test. 'So far the trouble students aren't impressive.'
It was finally time for the ball throw, and so far Aizawa was less than pleased with most of his class.
'Some are still not taking this seriously, and others aren't showing me any heroic drive or attitude.' Aizawa thinks. 'This 'best of the village' student is bottom of the class by a good margin at this point, does she even want to be a hero? Has she never exercised before in her life?'
"Alright, Megumin, your turn." Aizawa says, in a better mood because of Midoriya's performance.
'If only the other problem student's displayed such drive.' Aizawa thinks. "Get it over with, I don't have all day."
Megumin walks confidently to the circle staff in hand, smugly laughing at the simplicity of the exercise.
"Time to unleash my unfathomable power!" Megumin declares removing her eyepatch.
Of the students several, Izuku and Ochako, seemed to believe what she was saying and looked on with excitement while most looked on with mild interest.
Entering the circle Megumin holds her staff in her left hand and the ball in her right.
'I have a bad feeling about this.' Aizawa thinks.
"My name is Megumin!" She begins. "I am a user of the finest magic the Crimson Demons possess and I command explosion magic. Now come forth! Darkness blacker than black and darker than dark."
At this point several magic circles appeared around her and some kind of energy was being pulled into the gem, feeling the power the majority of the class retreated.
'The problem child didn't fall back.' Aizawa thinks, noticing Izuku and Ochako were still watching the charging Megumin without concern for their own safety. Before Aizawa could move to bring them back a green haired woman arrived out of nowhere and dragged them to safety.
Inko Midoriya, with more than a decade of experience dragging a distracted, note taking usually, Izuku from villain fights, had arrived after her mother sense had gone off.
And just in time to as Megumin finished her chant.
"...The time of awakening cometh. Justice, fallen upon the infallible boundary, appear now as an intangible distortion! This is the mightiest means of attack known to man, the ultimate attack magic!" Megumin shouts, throwing the ball forward as hard as she could.
"Explosion!" She yells firing a beam of energy at the ball, sending it a great distance before it exploded with a deafening roar. The shock-wave whipping the students as glass broke all over campus and alarms rang in police offices all over the city.
"It seems the ball disintegrated about 2 km from here." Aizawa says, noting that it was about the epicenter of the explosion.
The class and Ms. Midoriya was of course still in shock and didn't comment on the ridiculous score.
"Hurry up and get out of the circle, we have more tests." Aizawa says, noticing Megumin lying on the ground.
"Explosion magic is the strongest of magic, and therefore uses a lot of mana. More than I have, so as a consequence I can't move." Megumin says.
'And I thought I was in the clear after Midoriya' Aizawa thinks. "What good is a hero that needs to be rescued after beating one villain. I don't need the rest of the tests your..."
Before Aizawa could finish his sentence a challenger appeared.
"You think you can out do me at my own Quirk!" Bakugo yells, charging at a student for the second time. "You're dead! Demo B..."
Before Bakugo could finish his sentence Aizawa recovered enough from his progressing brain aneurysm to bind him in his capture tape again.
"That's it! I don't need the other tests I'm expelling people now!" Aizawa growls, beyond himself in irritation. "As I was saying Megumin, you're useless, Nezu can apologize to his friend all he wants but I won't teach any Crimson Demon! You're expelled."
"Wait really?" Momo says, not believing anyone would be expelled on the first day.
"I'm not finished yet." Aizawa says, his outward appearance calming down, but his inner mood unchanging.
"Bakugo, you tried to attack two students on the first day, you already had a dubious record from my research, get out of my sight."
"Ehh?" confusion rang through the class, not expecting a decent scorer to be kicked out.
"Mineta, you've been perving at the female students even as you should have been focusing on the tasks, you also had a dubious record so get lost, I'm not dealing with someone like you."
"What? No." Mineta sobbed as the class started to huddle together in fear.
"Kaminari, you're the most disappointing electric user I've had in my classes. I've seen no attempt to use your power in any of the tests. No short circuiting the grip tester and no railgun on the metal ball. You have no potential, good-bye."
"Todoroki, I know your quirk from your file, I told everyone to give it their all, and you've just used half your power, current second place doesn't even matter, your father's position doesn't matter, try your luck somewhere else."
As Aizawa stopped everyone remaining huddled in a group wondering who was next as Aizawa started walking away.
"What are you waiting for? We've wasted enough time, I still need your results." Aizawa says, seemingly back to his bored self. 'That was cathartic.'
"Hold on! I can't be expelled!" Megumin cries, "Lunch here was going to be my only meal of the day! How will I eat?"
She was ignored by the thoroughly shell-shocked class, but Ms. Midoriya slipped her a note with an offer for lunch and an address.
Nothing else of note happened during the tests an he decided to make Ms. Midoriya take the rest of them as punishment for somehow breaking into the school. And in the end both Midoriya's sat at the bottom of the ranking. It seemed to become a competition of which one could cry more as the area began to flood.
"What are you crying for, I already expelled everyone I wanted to." Aizawa says.
Unfortunately that only changed the cause of the tears, Aizawa tried to cancel their quirks, but apparently this was natural.
'I'm going to need a waterproof sleeping bag.' Aizawa thinks.
"I would treat you all to lunch but our apartment is too small." Ms. Midoriya says as the class collects their schedules from the classroom, "None of you should be alone after such an experience."
"Why not my place? I have plenty of room for all of you." Momo offers, "I'll have my driver bring the shuttle bus."
"As long as we stop by my apartment to pick up poor Megumin, I can't leave her without food and I already gave her the address." Ms. Midoriya says.
And with that the class had a fine lunch at Yaoyorozu's mansion. Megumin tried to become a guard in exchange for food and became friends with Tokoyami naming him an honorary Crimson Demon. Many tears were shed as the class recovered from the ordeal well into the evening.
AN: Well, that went way different than I expected, but I've had this idea in my head for quite some time and it needed to be written. I originally was only going to have Megumin expelled, but I then saw Bakugo angry about it and then Aizawa just snapped, carnage ensuing...
Also about the dubious files, I doubt Aizawa wouldn't look into his students before they even start and comparing Bakugo's behavior at his entrance exam to his fandom 'perfect record' or his canon probably less than perfect. I doubt Aizawa wouldn't have his eye on him and any major step out of line would anger him. The rest is just the results of rage, any flaw is exaggerated. Mineta's perversion, Todoroki's lack of effort... Kaminari is more of a me thing, as most anime electric users are way better than him...
Wait, you thought this would be a proper crossover with an established plot and character development?
...
You're serious?
...
Let me laugh even harder!