Thorny Path of a Pro-Hero

The very next day after school, we headed straight to the nearest subway station.

Silently. Together. Side by side.

I lazily thought about how the next day everyone around would be whispering and glancing over at us—kids, after all!—but I didn’t plan on doing anything about it. Firstly, it was beneficial for Yui; she should get used to attention if she wants to be a hero. Secondly... I didn’t care.

Yui's enthusiasm and determination weren’t exactly contagious, but they were genuine. In the notebook she had filled with her neat handwriting, there were some pretty sensible ideas. Nothing I hadn’t thought of myself, but that wasn’t the point—the goal was for her to try to come up with something on her own and break out of conventional thinking.

In the park that I knew well—the same one where I broke a tree as a kid—I headed straight for a favorite spot, a bench under the shade of an oak tree... or was it not an oak?.. I never really understood botany, or biology in general.

I sat down on the bench, and Yui, after hesitating, perched on the edge.

"So... from your 'essay,' I can see that you really put effort into your work and tried hard, well done," the girl blushed a little again. It seems she’s not used to receiving praise at all. Alright, one carrot handed out... "There are indeed some interesting and promising ideas in there. However, this is far from the limit. Moreover, it’s not even the tip of the iceberg."

Kodai listened calmly and attentively. Good.

"But before I start bombarding you with ideas and suggestions, how about you demonstrate your quirk to me—personally—and then I’ll ask a few clarifying questions. Deal?"

Yui nodded, stood up... and looked around for a suitable target. She chose a trash can that looked like a tin barrel. She touched it...

The trash can shrank to the size of a cup. It shrank in a strange way—not smoothly, but in jerks. As if... like in an anime where they saved on the frame rate.

I smirked.

Leaning down, I picked up the trash can with one hand. Light... as if I really was holding a cup. I gave it a little shake—there was a rustle and a clinking sound. Aha. Not empty.

God, what a cool superpower...

After I put the container back in place, Yui clasped her hands together as if she were about to wish me a good meal (Author's note: "Itadakimasu!"), and said:

"Release."

The trash can returned to its usual size. I noticed that the object hadn’t shifted in space at all, returning to its original size exactly where I had placed it. No bouncing, no falling. No transfer of kinetic energy, no changes except for weight, volume, and, presumably, density in proportion...

Although no, that’s still something that needs checking.

After rummaging in my pocket, I pulled out a ten-yen bill. I carefully tore a small piece from the edge and handed it to Yui, who understood without words what needed to be done—and increased it to the size of a medium dog.

I tried to tear the paper, now several millimeters thick, without using my quirk, and predictably failed.

Therefore, from practically any trash, plastic cap, or button, Yui could create a shield capable of withstanding, at a guess, a pistol shot. Not bad.

"Alright, Yui Kodai, have a seat," I "gallantly" patted the bench. "My first question is this: how long can you keep an item shrunk?"

"Not very long. I get tired... but I think I can do it for at least ten minutes."

"I see. You’re aware of the popular theory that quirks are like human muscles, and just as muscles can be developed through physical exercise, consistent quirk training with the right routine, repetitive exercises, and gradually increasing loads can develop them?"

"Y-yes, I’ve heard of that, but... I’m not sure I see how that applies. To increasing the duration of the quirk’s effect, I mean."

"And if you assume?"

"W-well... maybe I could carry a first aid kit..." she suggested hesitantly.

I clapped my hands a couple of times in a light round of applause.

"Exactly right! Or even more than one. But that’s not all—look: not all heroes specialize in fighting villains; many of them, like Backdraft or Thirteen, focus on search and rescue during accidents and disasters. Do you have any size limitations on the items your quirk can affect?"

The girl frowned in confusion. She hesitantly replied:

"I’m not sure about small items, but... a school desk is the biggest thing I’ve managed so far..."

"Got it. Suppose your quirk training could push that limit to... say, the size of a car. Sound good?"

"Sounds good," Yui responded obediently.

"As far as I understand, the internal structure of objects isn’t damaged? Electronics don’t malfunction after shrinking and unshrinking, right?"

"Mechanisms don’t work well in altered sizes and can break... but I haven’t noticed any issues after the quirk is undone... so, yes."

"In that case, theoretically, you could bring several ambulances or emergency response units to the scene of any incident! And why bring them? You could carry, say, a motorcycle—or even a scooter in your pocket—I’m sure you could already find a vehicle that you could shrink! Take it out of your pocket, unshrink it, and dash off to perform your heroic deeds. Now imagine how many lives you could save if, for example, during a fire, you could transport five fire trucks in your pocket right to the building!"

Wow, her eyes are so big right now, I’m starting to believe I’m in an anime.

And I’m just getting started.

"What does your quirk work on, anyway? What kinds of objects and matter? Does density matter?"

"On inanimate objects... not on people or living things—no... m-matter? Well... I don’t think I’ve noticed any patterns... everything enlarges—paper, plastic, metal."

"Organic matter? It doesn’t work, you say?" I squinted. "Five minutes ago, you 'shrank' the trash can. How about we check what was inside, huh?"

I stood up and pushed the lid off the trash can, motioning for the confused girl to follow.

A cautious examination—at a distance!—of the trash container showed that, yes, there was indeed organic matter inside. Apple cores, some leftover fast food.

Moreover, they were INSIDE the shrunk object, reduced along with it proportionally. Well, the question of how homogeneous the structure of the objects being altered needs to be is off the table—for lack of necessity.

Not at all.

I picked up an oval leaf from the tree under which we were sitting and handed it to Yui as a study aid. Like, enlarge it just like the bill—both are cellulose, after all... and for her doubts, I had an ironclad response—there were a few leaves like this in the trash can too.

Poor Kodai was almost about to start smoking from her ears.

Deciding to slow things down a bit, I handed her back the notebook with the description of her quirk and suggested she jot down the most important points—like the potential benefits of training for longer duration of size-altering effects and the need to attempt shrinking larger and larger objects.

Meanwhile, I was thinking. When she “shrunk” the trash can, I noticed that she didn’t need to touch the object with all five fingers, unlike, for example, the girl from the future 1-A class who controls gravity. So... does she just need to touch it with her palm?

Or just touch it?

Yui gently tugged on my sleeve:

"But I need to constantly concentrate on the altered object. How will I keep them that way for hours?.."

I smirked crookedly:

"If there’s one thing I can help with, it’s training for concentration like no one else."

But of course, I didn’t explain anything. I asked:

"Do you need to touch the object with your hand to shrink it?"

"Yes, direct contact is required," the brunette responded, slightly surprised. Well, yeah, why would I ask such obvious questions, right?

"With your hand?"

"Uh..."

"Can you shrink an object by touching it, for example, with your foot?"

Yui Kodai—blue screen.

A dozen seconds later, she managed to pull herself together and weakly asked:

"Why?"

I replied (mentally cracking my knuckles):

"As I understand it, you don’t see how your abilities could be useful in close combat. I can understand why. Besides, all heroes have their own specialization; there’s nothing wrong with ranged attacks and support roles..." I yawned and leaned back on the bench. "However, the reality is that any hero will eventually engage in close combat. In reality, you know, there are dark alleys, winding corridors, and smoky city streets. And so, regardless of your quirk's properties or personal preferences, you need to be prepared for that. Well, that’s how I see it."

Yui nodded slowly. I could almost feel new neural connections forming in her brain.

"But how could my quirk help in close combat?"

"It could help remarkably well!" I grinned. "In close combat, with your quirk, you could disable the opponent’s equipment! Shrink or enlarge elements of their armor or costume, causing them to lose balance or even become immobilized!”

“But how…” - the ordinary superhero schoolgirl, who I was rapidly molding into a Terminator, practically moaned.

“The simplest example is when you’re sparring in the dojo. I think you know that the floor there is often covered with mats. The moment your opponent makes a move, you touch the mat under them with your foot – and voilà! The opponent loses balance, opens up, and gets hit in the head by a future hero. Victory for Yui, hooray!” I slightly smirked, watching a faint blush appear on her cheeks. However, she didn’t look away, listening attentively. “Or, say, a villain sneaks into our school. The floors there are wooden. With your power, you could easily shrink a few planks in the floor, making them trip and lose control of the situation.”

“I think I understand… but I could never have imagined such an application for a quirk before…”

“But we can go even further. The limitations on the shape and boundaries of objects are quite arbitrary. I can't guarantee that this will work, but try delving into the study of physics - if you dig deep enough, you’ll realize that discrete units and whole objects don’t really exist in the world. We’re all made of cells, cells of molecules and atoms, all atoms consist of electrons and protons, all protons consist of quarks… Boundaries are not just blurred, they don’t exist. Do you understand? They are all up here.”

I tapped my index finger on my head and smiled as I looked into the wide-eyed girl’s eyes. I wanted to add that “there is no spoon,” but I was afraid she wouldn’t get it.

“But… for All Might's sake, all of this needs to be trained!” the girl suddenly exclaimed.

I frowned.

“Yes. That’s the whole point. By the way, speaking of training: I saw how you cancel your quirk - by folding your hands in prayer and announcing the action, saying something like ‘boom.’”

“Y-yeah?”

“Is that necessary?”

“… well… otherwise, it doesn’t work…” the girl shrugged uncertainly.

I continued to stare skeptically.

“… and other… heroes do it too…”

“…”

“… and it looks cool…” Yui murmured quietly, staring at her knees, blushing deeply from embarrassment this time.

I stopped teasing the cute girl and laughed.

“In any case, it’s your choice, and your allies should be kept informed. However, by doing this, you lose the element of surprise. In any case, we’ll be taught teamwork at U.A., so maybe they’ll suggest a less obvious way.”

“Well, I think I can skip saying ‘cancel,’” she suggested, “but if I don’t fold my hands, it doesn’t work…”

“Have you ever considered that this might just be a psychological limitation?”

The girl stared at me again, wide-eyed. I smirked.

“Try doing the same thing on your own time but differently - with a different hand position, a different word, not folding your hands completely, not folding them at all… I highly doubt that this is a necessary condition for your quirk to work - although, of course, in this crazy world, who knows…”

We sat in silence for a while. The leaves rustled quietly.

“Shoda, do you… do you think I’ll be able to get in?” Yui asked timidly, pulling her knees to her chin and hugging them.

“One hundred percent,” I replied. “Don’t doubt it.”

What more was there to say? I’d seen it with my own eyes.

Kodai didn’t say anything in response, but her shy smile was enough for me. It was the first one I had seen from her, by the way.

I slid off the bench and stretched.

Sunbeams ricocheted off the city skyscrapers, pierced through the dense foliage, and dazzled me as they tried to get into my eyes, playing with each other. I yawned again (Author's note: and you probably wanted to yawn too, admit it!).

“I think it’s time to head home. Gather your thoughts, think about training, make a plan. I’ll help if needed. And I think you’ve got enough information about the possibilities of developing your quirk… for now.”

“Is that not everything?” the girl asked, wide-eyed, jumping up from the bench.

“Nope. We haven’t even covered half.”

“O_O.”

Illustrations:

Yui has already settled in, no longer nervous, and is getting ready t̶o̶ ̶w̶r̶a̶p̶ ̶N̶i̶r̶e̶n̶ ̶a̶r̶o̶u̶n̶d̶ ̶h̶e̶r̶ ̶f̶i̶n̶g̶e̶r̶to be a good comrade.

Canonical superhero outfit for Yui.

Looks exactly like those guys who service race cars at pit stops.

Not a fan.

Will change.

Yui Kodai uses her quirk on a metal barrel. Note that she DOESN'T need to touch the object with all five fingers (the fandom wiki is wrong).

And forget about the pink glow from someone else's quirk, she has no special effects.

Nuff said.