Looking back, Izuku would never be sure when his quirk came in.

It wasn't something flashy and obvious like Bakugou.

Instead, there was a… pressure… inside his head.

It took time for him to work out what it could be, to quantify it, time in which there was concern from Inko and the Bakugous about how much longer his quirk would take to come in.

Finally he realised what it was, helped by the rants of a recently captured villain that had been recorded and put online.

"You don't know what it's like, having a pressure inside you just wanting to be used, to prove that it exists," the villain had snarled. "You heroes have it so easy! You got lucky with the exams and a school took you in, got you a license. Not me! I was kicked out on fabricated pretenses, had my chance taken from me! But not you. You all get to wander around, using your quirks as much as you like, never feeling that pressure. Why do you deserve to have the permission," he snorted derisively, "to be what you were always meant to be, when I don't?"

That pressure, it was the same as Izuku.

So, it was his quirk, waiting to be used.

By the time he had it figured out, labeled his normal state as 100% (as 0% just… didn't feel right), there was already a muttering that he was quirkless and that they (the Midoriyas, Bakugous and doctors) were just in denial.

And then in school (they had to be prepared for new quirks coming in after all) he experimented, dropping to 99%.

The pressure relaxed, but it felt like his body was going to burst.

He screamed, an unending outletting of pain, the other children ran away, afraid of getting the blame for whatever was happening.

98%

The teacher saw him, rushed forwards.

97%

The teacher lost his footing and was hurled back.

96%

The floor and ceiling started to crack.

95-

Izuku fought through the pain to clamp down on his quirk, forcing the power back.

100%

It was only the facts that he had never demonstrated a quirk before, nobody else had been injured and that the doctors the school ended up calling in found his muscles, tendons and cartilage had been badly damaged that kept him from getting in trouble.

And Izuku now knew better than to try using his quirk.

It was years more before he risked it, years of being the 'dangerous kid with an uncontrolled quirk' where only Bakugou stood by him, and then only because 'no way could Zuku beat him, even with a quirk'.

And then maths class introduced decimals.

Merely cracking open 1% had been damaging and destructive, opening the floodgates to more percentages leaking free, but 0.1%?

Still too much.

Not as immediately catastrophic as 1%, but still too much.

At least he was complimented on engaging in the quirk comprehension sessions for the first time and didn't suffer actual injury.

He tried again, at 0.01%.

He felt the strength gains, greater physical speed, and for the first time since he had used his quirk felt he could be a hero.

It ticked down to 99.98% and he felt his breath catch.

99.97%

99.96%

After some experimentation he discovered the count ticked down over the same period, always the last digit going down by one.

Use 0.01% and twenty seven seconds later he would be at 99.9%.

Twenty seven seconds later he would be at 99% and would start damaging himself properly.

Another twenty seven and he would reach 90%, where he would really start to risk himself, going by his experiences of the higher percentages.

And should he survive another twenty seven seconds without restoring his quirk, he would hit 0%.

Something shifted within him at that thought.

He didn't want to see what the consequences would be.

So overall, he could be a hero for less than a hundred and four seconds at a time, less than one and three quarter minutes.

And as that countdown continued, he would keep getting stronger and faster, but no tougher or more resilient.

… Then he would have to improve those on his own.

School wasn't too helpful, physical education classes usually focused on group activities and games.

In the end it was Bakugou who came to the rescue.

Like most of the class Bakugou was intent on becoming a hero, but unlike them had clearly decided that raw power from a quirk wouldn't be enough, and found a gym to help train him, inviting Izuku as his 'rival' (a definite step up from the class of 'extras') to train against him.

At first the instructors were surprised at how different the two were, not to mention their different focuses.

Bakugou focused on strength and learning to fight, relying on the secondary effects of his quirk to keep himself safe, while Izuku mainly focused on endurance and learning to fight.

It didn't take too long before everyone else stood back to let Izuku and Bakugou just spar with each other.

It was safer for them that way.

As the years passed Izuku found a definite result, reaching a level where he could use 99% for a couple of seconds, even as 98% was still too harmful.

And then came the fateful day they applied for high school.

[%]

When the teacher declared about everyone looking to become a hero, Izuku struggled not to laugh.

Of course everyone wanted to be a hero.

In recent years, relatively speaking, other jobs had started getting licenses for useful quirks, but only heroes had the right to use their quirk, whatever it was, for absolutely anything that didn't break another law.

And yet how many had put any kind of effort in to preparing?

It wasn't as though their quirks would be useless after all, as long as they were prepared.

Extending neck?

Scouting.

Wings?

Flight was always useful as long as you could actually do something when you got there.

"We even have two applicants for UA," the teacher declared, a certain greed just barely visible in his eyes.

It had long been obvious that the school wanted the prestige of teaching a future UA graduate, but Izuku was long disillusioned with their approach.

It mostly consisted of letting them get away with technically illegal quirk usage, 'so they would get stronger faster'.

No actual teaching or anything productive.

"Our strongest student, Bakugou of course," the teacher answered a question Izuku had missed. "Oh, and Midoriya."

Aldera was never entirely sure how to treat him. On one hand he had never shown off his quirk around the place, on the other they had the reports of the damage it had caused that first time and of course…

"Of course my rival will get into UA!"

… He had Bakugou in his corner.

"Yes, well we have classes to get on with so everyone settle down…"

[%]

While Izuku was definitely friends with Bakugou, that didn't mean he got on with his other friends.

As such, when Bakugou decided to spend time after achool hanging out with 'his bunch of extras' Izuku ended up heading home by himself.

Not the best decision he could have made, he realised as a villain ambushed him under a bridge.

"What a useful disguise you will be," the sludge villain giggled as they wrapped Izuku within their own body, attempting to suffocate him.

He panicked.

This was his first direct interaction with a villain.

His second instinct (there was no way for him to call for help with the villain covering his mouth) was to use his quirk.

It was technically illegal, but it was rare to charge someone for self-defence.

99.99%

He struggled, tearing a hole in the sludge around his arms that healed quickly, the villain fighting back.

99.98%

His struggle intensified, but he couldn't reach his face.

The villain was going to kill him.

99.96%

His struggles weren't helping, they were just using up his oxygen.

99.93%

"I am here," a voice called out, a burst of wind smashing the villain off him, and Izuku fell to his knees, gasping for breath.

100%

"Are you alright young man?"

He looked up, to see All Might, the number one hero.

Between the realisation that he had been personally saved by none other than All Might and his lack of oxygen, Izuku passed out.

[%]

Toshinori panicked when he saw the kid collapse, but brought his first aid training to bear and realised he had merely fainted.

Giving a sigh of relief at not being too late and letting a kid pay the price, he set to work containing the villain.

Since his fight against All For One he had been unable to eat proper food, which left him relying on sugar rich drinks more than he probably should, but at least had the side effect of having convenient bottles to store the villain in (once he emptied them of course).

With the villain out of the way and no longer a threat, he was able to turn his full attention to the kid.

In the struggle the kids bag had come open, revealing the student copy of a UA application form and a notebook labeled 'Hero analysis for the future'.

Unable to resist his curiosity about one of his potential future students he flipped it open.

As though it was fate, the book fell open on the page labeled All Might.

He felt his eyes widen at the depth of information the kid had collected and worked out.

This… was similar in quality to what a professional analyst could produce. And from an untrained kid?

Toshinori felt bad about looking now.

What to do to make up for it..?

Well, the kid was clearly a fan to have managed such a quality analysis, so the solution was simple!

He grabbed his emergency pen and signed the page on the empty space least likely to be saved for something in particular.

That done, he tucked everything back into the bag and closed it, before waiting for the kid to wake up again.

He was running low on time, but it wasn't as though he had any official duties for the rest of the day, so he could at least make sure the kid really was alright.

[%]

Izuku stirred awake, confused.

Why was he lying on the road?

"Are you alright, young man?"

The voice was familiar.

He looked up.

"All Might?"

The hero let out a laugh. "Indeed! I was chasing this villain," he held up a bottle containing sludge that did indeed look like the villain, "when he attacked you. I'm just glad I got here in time!"

Izuku was immediately bowing to him. "Thank you for saving me!"

"What sort of hero would I be if I didn't?"

The question brought up a different one in Izukus mind.

"Can I ask you something? How do you control it? Your strength I mean, you're so strong but you can control your strength enough to be a hero…"

It looked like All Might was trying to figure out an answer, but then he coughed suddenly.

"Sorry, I have to be off! I already spent a bit longer than I probably should have waiting to be sure you're alright, so farewell!"

He turned, making to jump, and Izuku found himself moving before he could think, grabbing hold of All Might as he left the floor, desperate for an answer whether his quirk could let him be a hero.

They didn't notice the bottle fall from All Mights pocket.

[%]

Bakugou was walking down the street in a mood, having separated from the extras.

It pissed him off, the way they kept talking about Izuku as though he was weak.

As though he would have a weakling as a rival!

No, he still remembered that day in school when Izukus quirk came through.

How Izuku merely screaming had blown away the teacher, caused the floor and ceiling to start breaking apart, the sight of some kind of battle aura around him like an anime…

And that had only been 95%, from what Izuku had said about it later.

Sure, that just left 5% more to go, but the quirk wasn't at full strength yet, was it?

His explosions kept getting stronger, so Izukus new 95% would be greater as well.

And as for 100%?

Bakugou found himself grinning at just the thought.

So it pissed him off when people dismissed Izuku due to him not using his quirk, as though it meant it was weak.

He wasn't weak, he was too strong!

But that would only make his story the greater, that when he became number one it would be with his rival whose true strength would rival All Might standing beside him as number two, both having risen together from nothing.

He spotted a bottle on the floor, and moved to kick it, just another piece of trash to take his mood out on, only to stop at the sight of an eyeball rolling about within.

He froze, before grabbing the bottle.

He needed to take it to the police or a pro hero.

They needed to know about someone putting sludge and body parts into bottles.

[%]

"I'm sorry!"

Izuku had let go of All Might as soon as they reached the roof and it was safe to do so.

"It's just… I want to be a hero, but my quirk… I can only use it for brief periods," he explained, not yet able to look up at All Might. "And… it's too strong, I don't know if I can hold back enough to do anything!"

He finally looked up, to see a skeletal looking man standing before him, wearing the same clothes as All Might had.

"You… you have a time limit on your quirk too," he burst out.

Skeletall Might coughed, blood flying from his mouth.

"You're hurt!"

"Not exactly," he interrupted, voice lacking the power and depth of All Might. "To either, I guess. A few years ago a villain got a lucky hit in, and now I can only hold my muscle form for a few hours a day. Nobody has been able to heal me, and if I try to push it too far the injury pushes blood into my lungs."

He sighed.

"I have to try and fit my entire day of heroics into just three hours, or risk villains seeing my days as symbol of peace are dwindling and act out even more than they do now. Trying to be a hero with a time limit… what can you manage?"

"Fifty four seconds, fifty seven at a stretch, before it starts to damage me," Izuku admitted. "But if I reset it, I can can get another fifty four as often as I want!"

"And that's just under a minute at full strength?"

Izuku hesitated.

"Not exactly. The longer I have my quirk active, the stronger it gets. That's why I can only go down to 99% right now. Er, I loosen my quirk to get stronger, so I label normal levels of strength as '100%' and then reduce the percentage as I grow stronger."

"You mean to say you can only use 1% of your quirk before it harms you? Young man, I don't think you can be a hero with a quirk so dangerous to yourself."

"I just need to learn how to manage the strength and get tougher," Izuku protested. "It used to be I could barely manage 99.9%, so I know to build my body up. I just… I need to know how to keep my strength in check and avoid doing more damage to people than I need to! And I'm sure, if I just keep training, I will be able to hold the percentage in place and fight for as long as I need to!"

It was only after he was finished that Izuku realised he'd just been ranting at All Might of all people.

"I'm so sorry! It's just that I have to be so careful with my quirk that a lot of people don't think I have one and my frustration with them just built up and-"

"It's alright young man. If you are so sure you can be a hero, I will not stand in your way. And as for control? The only advice I have is practise. Find something to test your strength, something that will help people and use that to get your own measure. Do so, and take two steps towards being a hero!"

This was why All Might was such an inspiration, Izuku realised.

He didn't need a speech prepared by some pr guy, when someone came to him needing help, he could find the words he needed by himself.

"Yes sir!"

[%]

The months passed quickly.

Izuku had looked for something he could do to help people and train his control of his quirk at the same time, and quickly discovered a local beach that had become a dumping ground for trash.

He had hesitated at first, as doing anything would technically involve illegal quirk usage, but it was advice from All Might (and the police clearly didn't cone by often, otherwise there wouldn't be so many piles of junk), so he added the beach to his weekly routine.

At first he just tried clearing what he could, figuring out just how strong he was at various percentages, but that didn't exactly translate directly to judging his punching strength.

Then one day Bakugou followed him, curious as to where he kept running off to.

When Izuku told him it was advice from a hero (not mentioning any names) in order to learn how to use his strength safely and help people at the same time, he scoffed before joining in and pointing out that he needed to try out hitting things while using his quirk.

It took some work, but Izuku started making real progress towards using his quirk safely, and between the two of them the beach was cleared before the UA entrance exam.

And the cleared beach even served as a reward for their efforts.

As Izuku turned to leave the beach Bakugou stopped him.

"You better get in. It wouldn't be the same without my rival."

[%]

Izuku all but collapsed into his seat in the auditorium.

The day so far had been a mess of ups and downs.

First he had tripped on his way into UA, only to be saved from falling by a girl who was also here for the exam (who he nearly talked to). Then came the written test, which he had been quietly confident about, but turned out much harder than he expected.

And now they were finally going to be told about the practical test.

"Can I get a yeaah," called the unmistakable voice of Present Mic.

"Yeah!"

It took Izuku a moment to realise it was him that had spoken, a result of his sheer nerves.

He sank back into his seat at the sudden attention from everyone, thankful that Bakugou at least seemed to be ignoring it.

"That's what I'm talking about," Present Mic responded, shooting a grin in Izukus direction. "Can't be a hero if you can't take the attention, am I right?"

Thankfully for Izuku he didn't spend long on the introduction, and instead started explaining the test, going over it in more detail than the handouts they'd been given.

Izuku started looking through the handout while listening to Present Mics presentation.

A frown crossed his face when Mic came to the explanation of the three types of robot.

There were four in the handout, three corresponding to what Present Mic was talking about, marked with the numbers 1, 2 and 3 of course, but the fourth without any such label.

Was it a mistake? A 'civilian' to be avoided or protected? Just an-

"Quit the muttering," Bakugou snapped, not bothering to keep his voice down and ignoring the glares he was drawing from everyone nearby. "He hasn't finished-"

A voice from higher in the auditorium interrupted him.

"Excuse me, but there are four robots on this handout. If this is a mistake it gives a poor appearance to somewhere as prestigious as UA. And further," the boy turned to face the two of them directly, "this is no place to distract people with muttering or conversations!"

"Oh, so it's fine to interrupt the explanation for a detail he," Bakugou nodded towards Present Mic, "hadn't yet got to, but someone trying to work it out for themself is too much? And it's fine for you to call across the room to tell him to be quiet, but the person next to them can't?"

The boy was reduced to spluttering, clearly having not considered there was anything wring in what he was doing.

"Not how I would have put it, but you have a point little listener," Present Mic stated. "And in answer to your question the fourth type of robot is an obstacle, worth zero points! It exists solely as a challenge to be avoided. Everything clear? Right, altogether now. Plus ULTRA!"

Near enough all the auditorium joined in on UAs motto.

[%]

Izukus nerves were back in full force by the time he reached the testing area.

At least Bakugou had gone to a different area.

And the girl who had caught him at the entrance was assigned to his area, he had a chance to thank her!

"Are you thinking of distracting that girl, like you distracted people when Present Mic was explaining the excercise," demanded the boy from the auditorium, getting in his way.

"Sorry," was about all Izuku could manage in response, intending to explain that he was intending to thank her and hadn't realised he'd been muttering, before Present Mics voice came over speakers.

"And GO!"

There was a pause where Izuku tried to figure out what was happening.

"There are no countdowns in real life," Present Mic reminded them, and Izuku realised the time was counting down.

He turned back towards the city area, and chased the others in.

He was keeping his power in reserve, at least for now, rather than risk it drop too low to control before he found a robot.

[%]

Toshinori watched the monitors showing the practical test, not entirely sure why he was here.

It wasn't as though he had any experience of this side of the test after all.

He caught a glimpse of a familiar head of green hair, the kid who had discovered his secret and dismissed it as another quirk with a time limit.

The kid was lagging behind the others in his area, and wasn't showing any obvious signs of using his quirk even when he did encounter the robot villains.

If he hadn't heard about the limits the boy had, Toshinori probably wouldn't have realised he was amplifying himself before each punch.

As the test progressed, he wasn't the highest scorer of villain points, but then again he wasn't the lowest scorer either.

Even the occasional cluster of villain bots wasn't enough to help him catch up with the scoreboard leaders.

"Time for the Zero Pointers," the principal declared, prompting Power Loader to press the button.

With a shudder a Zero Pointer started to emerge in each of the city areas.

[%]

Izuku felt the ground shudder, and turned away from the group of robots he'd just taken care of to see the Zero Pointer emerge, answering the question of where it had been hiding.

A momentary thought crossed his mind, that if he dropped his percentage low enough he could take it out with one hit.

Best not to risk it though, he was currently below 99% after running into a group of robots rather than the solo ones in most of the area.

He turned from the Zero Pointer, planning to get clear and reset his quirk, when he heard a cry for help, from between him and the Zero Pointer.

He didn't pause to think, instead Izuku dashed straight for whoever needed help.

He found her, shortly before the Zero Pointer reached them.

It was the girl from earlier, trapped under a piece of rubble.

There wasn't any way for him to get purchase on the rubble, he quickly discovered, blood pounding in his ears.

For a brief moment he considered smashing it to get her clear, but there was no guarantee he wouldn't harm her in the attempt.

He slowly turned to face the approaching Zero Pointer.

There was one thing he could do to protect her.

He leapt towards the Zero Pointers head, readying a punch.

The one single blow was enough to destroy the robot.

And then he was falling.

He checked his current percentage, already preparing to reset.

He was at 90%.

He forced himself back to 100%, and suddenly the world caught up to him.

His legs and arm felt worse than anything he'd ever experienced before, the slightest attempt to move sending even worse pain through him.

Falling unconscious was practically a relief.

[%]

Inko was worried for Izuku.

She hadn't really considered what the UA entrance exams would entail until they contacted her to tell her Izuku was injured.

They didn't give any further details, which was hardly reassuring.

There was the sound of the door opening, followed by Izuku callung "I'm home!"

She was already heading through to see him.

"Are you alright? They called me to say you were injured but…"

"I'm fine, they have Recovery Girl remember? She fixed ne up."

"But what happened?"

"Someone was trapped, I had to use too much of my quirk to save her…"

It wasn't entirely UAs fault then, and he was fine now.

Inko felt herself statt to relax.

"And who is this girl," she found herself asking.

"Mum!"

[%]

Time passed, and Izuku received his acceptance message from All Might (learning about how they were scored on 'rescue points' as well as 'villain points'), and finally made it to the classroom.

Having the initial introductions between the class being interrupted by their teacher declaring they would be doing some kind of quirk assessment test, and that whoever scored worst would be expelled, wasn't exactly a good thing.

If he was able to know how long before it would be his turn for each event, he would be able to unlock enough of his quirk to get a good score.

Instead he was only able to start letting his power out shortly before each event, facing them with 99.9 or 99.8% more often than not.

Everyone else seemed to be managing at least one outstanding score, while he was only managing average scores, which left him in undeniable last place.

All things come to an end, and time came for the final event, the ball toss.

[%]

Izuku breathed slowly, starting to let out his power.

99% would be dangerous, but 99.6% even would be nowhere near enough.

Instead he waited, letting the power build.

99.5%

99.4%

"What's the hold up," soneone asked, but Izuku ignored them.

This was the first event that let him build up his power at the start, rather than force everyone to go at the same time, and he would make the most of it.

99.3%

He moved his arm, ready to throw.

99.2-

0%

There wasn't the crippling pain or instant death he had expected from hitting 0%, just an intense feeling of wrongness.

Sonething cracked.

"Stop," he forced out, barely able to breathe.

"Wha-"

"Stop it!"

100%

He collapsed to his knees, breathing hard, before lookibg up and fixing the teacher, Eraserhead it had to be, with a glare.

"What the hell were you thinking," he demanded, too full of adrenaline to care what anyone thought about him.

"What happened to you?"

He looked down at himself.

There were cracks running through the air around him, as though reality itself had shattered.

He clenched his fist and glared at Eraserhead again.

"What gave you the right to just negate my quirk, without doing anything to understand what it was first?"

"The practical exam, you couldn't control your quirk and badly injured yourself. I wasn't about to let you-"

"You saw me injure myself saving someone and just decided I couldn't control my quirk at all?"

"You didn't use your quirk anywhere-"

"Yes I did! It takes time to let out enough of my power to do anything impressive, but let it get too strong and… and things like thr Zero Pointer happen! I need enough warning to get the right level safely! And what, you just assumed I could either hit 'badly injure self' level ir was at 'normal human' level and would go all out for the last test? Of course I would, that's how you set it up! There was no 'complete these tests without injuring yourself' so anyone who couldn't control their quirk would go all out at the end, what right do you have to just go 'no, you don't get to use your quirk in this quirk assessment test'? Did you just assume everyone would be fully trained with using their quirk? Well newsflash, people aren't legally allowed to use their quirk in public and not everyone can afford somewhere private to train with their quirk! And one more thing, this is all about testing us to see if we can be heroes? How well would you do in this test? Your quirk doesn't help you with any of these tests, so what could you do to pass? Oh right, sabotage everyone else."

There was near silence at his words, broken only by his panting as he tried to get more blood in his adrenaline stream.

"That is your first lesson here," Izuku said quietly. "If you can't do well yourself, sabotage everyone else."

He felt defeated.

"I'm done," he said simply.

"What do you-"

"Since I had my quirk, I knew that hitting 0% would be dangerous, and first day you just shut it down, and now look," he indicated the cracks that were still filling the air around him. "This? This is on you. I'm done, I am leaving. I am not about to take the chance of you deciding to just randomly shut my quirk down again for whatever bullshit reason you cone up with and risk thr consequences of hitting 0% for any longer."

He turned and walked away, ignoring what everyone was saying behind him.

It had been his dream to study at UA all his life.

And now, thanks to one teacher, he couldn't take the chance.


AN: Was reading Hero Academia fanfics, noticed how nearly everyone seems to have Aizawa erase Izukus quirk, and decided to do something where this is a serious problem. It also felt like a good place to show exactly why Aizawas 'logic' about the situation isn't logical at all.

There are different types of logic for people to rely on, and Aizawa still comes off as highly illogical, just deciding what he wants to do and then justifying it rather than letting logic render the course of action. He may be a decent character and a good hero, but he is a lousy teacher.