Six Months Later
The neighborhood park was Izuku's favorite place, even if it hurt a little now. Before the diagnosis, he'd come here and imagine himself using his future quirk to save people, to be a hero. Now, at four and a half, he came here with his notebook, watching the other kids play and taking notes on how they used their developing quirks.
Kaito sat beside him on the bench, practicing his heat vision control by carving intricate patterns into a piece of scrap wood. At nine years old, his control had become incredibly precise—he could adjust the temperature and intensity to do delicate work or, if needed, cut through steel.
"That's a really good analysis, Izu," Kaito said, glancing over at his brother's notebook. Izuku had been documenting how their friend Tsubasa used his small wings for enhanced jumps rather than true flight. "You noticed he uses the momentum from his wing beats to change direction mid-air. Most people wouldn't catch that."
Izuku beamed at the praise, his pencil moving faster. Ever since getting the notebook, he'd filled nearly thirty pages with observations, hero video analyses, and strategic ideas. It helped—focusing on the technical aspects of heroism rather than dwelling on what he couldn't do.
"Deku!"
Both brothers looked up at the familiar, aggressive voice. Katsuki Bakugo stomped toward them, his two friends Tsubasa and another boy flanking him. At nearly five years old, Kacchan had grown more confident and, unfortunately, more abrasive since getting his explosion quirk.
"Oh, hey Kacchan!" Izuku smiled brightly, closing his notebook. Despite everything, he still considered Katsuki a friend. They'd known each other their whole lives.
"Don't 'hey Kacchan' me, you quirkless loser!" Katsuki snapped, tiny pops of explosion crackling in his palms. "What are you even doing here? This is where kids with quirks play!"
Kaito's eyes narrowed, his heat vision fading as he set down his wood. "Katsuki, that's enough."
"Stay out of this, Kaito!" Katsuki's face flushed red. It was a sore spot for him—no matter how much his quirk developed, Kaito's powers were on a completely different level, and everyone knew it. "Your loser brother doesn't belong here!"
"Kacchan, I'm just watching—" Izuku started.
"Watching? Like some kind of stalker? You're never gonna be a hero, Deku! You're quirkless! You're nothing!" Katsuki's hand shot out, snatching the notebook from Izuku's lap. "What's this? 'Hero Analysis'? Are you kidding me?"
"Give it back!" Izuku reached for it, but Tsubasa blocked him with his wings.
Kaito stood up slowly, and the temperature around them seemed to drop. "Katsuki. Give him the notebook. Now."
"Or what?" Katsuki challenged, but there was a tremor in his voice. Even at nine, Kaito's presence could be intimidating when he was angry. "You gonna beat me up? Everyone knows you're too much of a goody-goody to actually fight."
"I don't need to fight you," Kaito said quietly. "I just need you to do the right thing."
"The right thing?" Katsuki laughed harshly. "The right thing is for Deku to give up on this stupid hero dream! He's just gonna get himself killed!"
With that, Katsuki channeled a small explosion into his hand and blasted the notebook, scorching its edges. Then he threw it over the fence into the pond below.
"No!" Izuku cried out, scrambling toward the fence.
Kaito moved faster than any of them could see. One moment he was standing by the bench, the next he was in front of Katsuki, his hand gripping the smaller boy's wrist. Not hard enough to hurt, but firm enough that Katsuki couldn't pull away.
"You think being strong means you can bully people weaker than you?" Kaito's voice was calm, but his eyes—his eyes were glowing faintly blue, and everyone in the park had gone silent. "You think having a flashy quirk makes you better than my brother?"
"Let go of me!" Katsuki struggled, explosions popping uselessly against Kaito's invulnerable skin.
"Izuku has more courage in his little finger than you have in your whole body," Kaito continued. "He faces every day knowing the world says he can't achieve his dream, and he still tries anyway. That's what a real hero does. What you just did? That's what a bully does."
He released Katsuki's wrist and in a blur of motion, dove off the fence. The other kids rushed to look over, gasping as they saw Kaito hovering above the pond, Izuku's notebook in hand. He landed lightly back on the grass, water droplets evaporating from his skin with barely a thought.
Kaito walked past Katsuki without another word and knelt beside Izuku, who was crying quietly, trying to hide his face.
"Here, Izu," Kaito said gently, holding out the notebook. It was singed and waterlogged, but most of the pages were intact. "It's okay. We can dry it out. Your notes are still there."
"I'm sorry," Izuku sobbed. "I'm sorry I'm so useless, Kai. You always have to protect me—"
"Hey." Kaito pulled his little brother into a hug, not caring about the other kids watching. "You're not useless. You're not weak. And you never have to apologize for who you are."
Behind them, Katsuki stood frozen, his face a mixture of shame and anger. His friends had backed away, uncertain.
"You want to know something, Katsuki?" Kaito turned his head slightly, still holding Izuku. "You've got an amazing quirk. You could be a great hero someday. But not if you keep acting like this. Heroes don't tear people down. They lift them up."
With that, Kaito stood, keeping one arm around Izuku's shoulders. "Come on, Izu. Let's go home and fix up your notebook. Then maybe we can watch that new All Might rescue video."
As they walked away, Izuku clutching his damaged notebook to his chest, the other children parted to let them through. Several looked at Izuku with new eyes—if Kaito Midoriya, the most popular and powerful kid in the neighborhood, believed in his quirkless brother that much, maybe there was something special about Izuku after all.
That Evening
Inko found both boys at the kitchen table, carefully using a hair dryer on low heat to dry out the notebook pages. Kaito was using his heat vision with surgical precision to evaporate water without damaging the paper further, while Izuku gently separated pages that had stuck together.
"What happened?" she asked, noticing the scorch marks on the notebook cover.
"Kacchan happened," Kaito said, his voice tight. "But we handled it."
Izuku looked up at his mother, his eyes still red from crying but his expression determined. "Mama, can Kai teach me to fight? Like, real fighting?"
Inko's eyes widened. "Izuku, you're only four—"
"I need to be stronger," Izuku interrupted, his voice small but firm. "I can't have a quirk, so I need to be better at everything else. Smarter, faster, tougher. Kai said he'd help me, but I want to ask you too. Please?"
Kaito looked at his mother seriously. "I've been thinking about it, Mama. If Izuku really wants to be a hero, he needs every advantage he can get. I can train with him, teach him what I know about combat and strategy. And I'll never push him too hard—I promise. But he needs this."
Inko looked between her two sons. Kaito, nine years old and already thinking like a pro hero. Izuku, barely past four, with a dream that everyone said was impossible.
She thought about telling them no, about protecting Izuku from the harsh reality that awaited him. But then she saw the determination in both their eyes, the unshakeable bond between them.
"Okay," she said softly. "But we do this right. Tomorrow, we're enrolling both of you in a proper martial arts class. And Kaito, you're not to use your strength when sparring with Izuku. Regular human level only."
"Of course," Kaito agreed immediately. "I'd never hurt him."
"And Izuku," Inko knelt down beside her youngest son, "this is going to be hard. Harder than anything you've ever done. Are you sure this is what you want?"
Izuku looked at his brother, then back at his mother, and nodded with absolute certainty. "I want to be a hero, Mama. Like All Might. Like Kai. Even if everyone says I can't, I have to try."
Inko pulled both boys into a hug, tears streaming down her face. "Then we'll try together. All three of us."
Later That Night
Izuku lay in his bed, the repaired notebook on his nightstand. Kaito had helped him reinforce the cover with clear tape and even drew a small symbol on the front—a star with a plus sign, representing both of them together.
"Kai?" Izuku called softly into the darkness.
From the other bed, his brother's voice answered. "Yeah, Izu?"
"Do you really think I can do it? Become a hero without a quirk?"
There was a pause, and then Kaito's silhouette sat up in the dim light from the window. "You want to know a secret?"
"What secret?"
"I don't just think you can do it, Izuku. I know you will. You want to know why I'm so sure?"
"Why?"
Kaito's eyes caught the moonlight, shining with absolute conviction. "Because you're my little brother. And I've never met anyone with a stronger heart than yours. Your quirk isn't powers, Izu. Your quirk is that you never give up, no matter what. And that's rarer and more powerful than anything I can do."
Izuku felt warmth spreading through his chest, pushing back the darkness of doubt that had lived there since the diagnosis.
"We're gonna do it together, right?" Izuku asked. "Both of us at UA?"
"Both of us at UA," Kaito confirmed. "And then both of us as pro heroes. The Midoriya brothers, saving people with smiles on our faces."
"Like All Might."
"Better than All Might," Kaito said with a grin Izuku could hear in his voice. "Because there's two of us."
Izuku laughed, the sound lighter than it had been in months. "Kai?"
"Yeah?"
"Thanks for being my brother."
"Always, Izu. Always."
As Izuku drifted off to sleep, he dreamed not of the quirk he'd never have, but of the future he'd create. A future where a quirkless boy and his impossibly powerful brother stood side by side, proving that heroes came in all forms.
And somewhere across the city, All Might finished his patrol, unaware that two young brothers had just made a promise that would one day change the world of heroes forever.