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My teachers son?

Summary:

After Shinsou runs away from home and finds his favourite teacher working after hours at school, he gets taken into his home and brought into his life style just to fall in love with his son. Y/N.

-erasermic
- I wrote this a few moons ago and forgot bout it whoops
- mini age gap like 1 year
- no smut

Chapter Text

You’d started noticing it slowly at first how your dad coming home later and later now that the school term had begun. At the start, it felt normal. Just boring paperwork, long teacher meetings, the usual grown-up stuff. But then… he kept “forgetting” his capture weapon at school. More than once. And that was definitely not normal. It didn’t take long before Hizashi cracked. Apparently, Aizawa had been secretly training one of his students. Private tutoring. Extra work all so they could make it into the hero course.

But you had never even met this kid. So obviously, your brain filled in the blanks. You imagined someone weak. Shy. Kinda useless, if you were being honest. The type who tripped over their own feet and couldn’t control their quirk properly. Probably had some weird, not-helpful-in-fights kind of ability too. Honestly? You had no real clue since you were still in primary school after all. Your last year before you’d graduate and (hopefully) make it into U.A. High.

Still. You had opinions. You sighed dramatically, sprawled across the couch with your legs spread out, your tail swishing lazily behind you. It flicked back and forth until-‘Thwamp’. Mochi, your very real and very grumpy cat, hissed in annoyance from where your tail had smacked him again. “Oops,” you mumbled, not sounding very sorry.

On the floor, Eri sat at the coffee table, completely focused on her drawing. Crayons scattered everywhere as she carefully added more details to her stick figures of you, her, Aizawa, Hizashi… and, of course, a whole army of cats. It’d probably end up pinned to the fridge like all her others. It was late. Rain tapped softly against the windows, sliding down in streaks and thunder rumbled quietly in the distance. Hizashi had already made dinner for the four of you, like always but Aizawa still wasn’t home.

“Dad” Eri’s small voice broke the quiet. “When’s dad coming home?” Hizashi stood by the sink, staring out the window for a second before shrugging. “Dunno, kiddo. Said he had extra work today.” He glanced at his phone. No messages. Nothing. He sighed, turning back to the dishes, letting the warm water and bubbles fill the sink. “Don’t worry,” he added, softer this time. “He’ll be here soon.”

Eri didn’t look convinced. You watched them both for a moment before yawning, stretching your arms and paws out in front of you. “Hey… what’s the student like?” you asked. “The one he’s training.” Hizashi paused, glancing over his shoulder. “His class?”

“No, the private tutoring.” “Oh.” He went back to washing, the sound of running water filling the kitchen. “He’s… a quiet kid,” he said after a moment. “Doesn’t talk much. Had a rough past.” That was it. Not very helpful. You huffed quietly, but another yawn cut you off. “I’m going to bed.” “Me too,” Eri added, rubbing her eyes. “Alright, night you two,” Hizashi said with a small smile, though it didn’t quite reach his eyes.

Thunder cracked loudly outside, lighting up the sky for just a second as rain poured harder against the windows. In the bathroom, you stood at the sink brushing your teeth, watching your reflection. Beside you, Eri balanced carefully on her little stool, doing the same. She was still so small only four her horn barely noticeable against her hair. You wiped your mouth, smoothing down your whiskers and blinking sleep from your eyes.

“When do you think dad will come home?” Eri asked quietly. You paused, then shrugged, giving her a small, reassuring smile. “Probably soon. Don’t worry about it, Eri.” Your ears twitched at the steady rhythm of the rain, oddly comforting. You both headed to bed not long after. And as soon as your head hit the pillow, you were out fast asleep, wrapped in the soft sounds of the storm. Completely unaware of the trouble unfolding at your father’s school that very night.

-

“Shut up, son!” ‘SMACK!’ The sound rang sharp through the house, louder than it should’ve been, like it echoed inside Shinsou’s skull instead of the room. “You’ve wasted all of our money just to get into the support class!?” “I told you it’s not my fault!” Shinsou snapped back, voice cracking despite how hard he tried to steady it. That was a mistake. Another hit, harder this time. His head snapped to the side, one eye squeezing shut instantly as pain bloomed across his face. His nose burned, then went warm too warm and he didn’t need to touch it to know it was bleeding.

“Don’t talk back to me!” his father barked. Before Shinsou could even recover, something struck him from behind his mother. The force sent him stumbling forward, barely catching himself before he hit the ground. “Shinsou,” she hissed, voice sharp and cold, “all you ever do is disappoint us.” He swallowed hard, breathing uneven. His hands clenched at his sides but he didn’t raise them. He never did. “Can’t you do anything right for once!?” his father yelled, grabbing him roughly by the collar, fingers twisting into his tie and yanking him forward.

“I tried!” Shinsou shouted back, anger finally breaking through the fear. “I did everything I could!” That earned him another punch. Right to the face. Everything went white for a second. Shinsou hit the floor hard, the impact knocking the air from his lungs. His ears rang, a dull, suffocating sound that drowned out everything else for a moment. He tasted iron. His vision blurred.

Above him, their voices kept going but it all blurred together now. Yelling. Accusations. Disappointment. Always disappointment. “You’re useless” “Waste of space” “Why can’t you be normal!?” His fingers curled against the floor. He didn’t fight back. He never fought back. But something inside him something small and quiet finally broke.

“I didn’t choose this quirk!” he shouted, voice raw, shaking as he forced himself up onto his elbows. “I didn’t choose any of this!” The room filled with the hush of their shocked faces. “Don’t you dare blame that on us.” Another shove. He fell back again, shoulder slamming into the ground. His chest tightened. It was getting hard to breathe not just from the hits, but from everything pressing down on him at once. The anger. The hurt. The exhaustion.

“Why couldn’t you try more Shinsou?! You’re such a fucking waste of money!! We spent everything on you! We wasted years looking after you and this is the respect we get!?” Every word hit straight to his heart.

He couldn’t do this. Not tonight. Not anymore. Before they could grab him again, Shinsou scrambled up stumbling, nearly slipping then bolted. “Get back here!” his father shouted. But he didn’t stop. He ran down the hallway, heart pounding so loud it drowned everything else out, and slammed his bedroom door shut behind him, locking it with shaking hands.

His breathing was messy, he stared at the locked door hearing the sounds of loud foot steps approaching and he turned back to his room. He had to hurry. He grabbed his old bad, half-broken zipper shoving things inside without thinking. A phone charger. Whatever cash he had stuffed in a drawer. A hoodie. His hands were shaking so badly he dropped the coins twice before finally managing to shove them into his pocket. Outside his door, footsteps.

“Shinsou!! open this fucking door!” He didn’t. Instead, he pushed open his window. Cold air rushed in immediately, along with the sound of rain heavy, relentless, pouring down like the sky had split open. Perfect. Without letting himself think because if he thought, he might stop he climbed out, slipping down the drain pipe and falling into a bush. The drop wasn’t far, but it still hurt when he hit the ground. He stumbled, nearly falling again, but caught himself.

Then he ran. Rain soaked him instantly, drenching his clothes, his hair, washing the blood from his face and mixing it with the water dripping down his skin. He didn’t know where else to go. So he ran to the only place that made sense. School. By the time he got there, he was shaking not just from the cold, but from everything. His body ached, every step heavier than the last, but he kept going.

The building was dark. Quiet. But not completely. One room had a light on, the staff room. His chest tightened as he reached the door, hesitating for just a second before pushing it open. There he was. Aizawa. Sitting at his desk, papers scattered around him, looking up the moment the door creaked open.

For a second, neither of them said anything. Rain dripped from Shinsou onto the floor. His breathing was uneven, his face bruised, his clothes soaked through, his eyes teary and red. “…Shinsou?” Aizawa’s voice was low, but sharper than usual. More alert. Whatever Shinsou had been holding together the entire run over whatever thin thread keeping him standing. Everything tore to shreds. “…I-i- d-didn’t know where e-else to go,” he said, voice barely above a whisper.

Aizawa was on his feet before the words had even fully left Shinsou’s mouth. That quiet, broken admission hit harder than anything else. “Shinsou..,” Aizawa said gently, already shrugging off his capture weapon and scarf, setting them aside without taking his eyes off him. His voice had lost that usual dry edge now it was softer now, steadier. Careful. The sound of rain still whispering on the windows.

Up close, it was worse. Bruising already forming. Blood, half-washed away by the rain, still trailing faintly from his nose. His clothes clung to him, soaked through, and he was shaking, not just from the cold. “Sit down,” Aizawa said, pulling his chair out, but Shinsou didn’t move. He stood their shaking, frozen, unable to move now his ankles were wrecked from the fall and he was painted in bruises.

Instead, he stepped closer, slow, deliberate giving Shinsou time to react, to pull away if he wanted. He didn’t. So Aizawa gently guided him down into the chair anyway, a hand steady on his shoulder. “You’re safe here,” he said quietly. “No one’s going to touch you.” Shinsou’s breathing hitched, and suddenly it was like everything he’d been holding back shattered all at once.

“I- I didn’t-..” his voice broke, and he clenched his fists, trying to stop it, trying to not fall apart. It didn’t work. Tears spilled over anyway. Aizawa didn’t say anything for a moment. He just moved grabbing a spare blanket from the back of the room, wrapping it around Shinsou’s shoulders carefully, like he might break. “Breathe,” he murmured. “Slow. You’re alright.” Shinsou shook his head, shoulders trembling. “I’m I- I’m sorry-” “Don’t apologise.”

Firm. Immediate. Aizawa crouched slightly in front of him, just enough to meet his eye level without crowding him. “You didn’t do anything wrong.” That only made it worse. Shinsou let out a broken sound, somewhere between a sob and a breath, and before he could stop himself before he could think he leaned forward.

Aizawa caught him without hesitation. One arm came up around his back, the other steadying his shoulder, pulling him into a firm, grounding hold. Not tight. Not suffocating. Just… there. Shinsou’s grip twisted into Aizawa’s shirt as he cried, quiet at first, then harder, the kind of crying that hurt like it had been building for years. Aizawa didn’t rush him. He just stayed there, one hand resting lightly against the back of his head, keeping him steady. “I’ve got you,” he said softly. “You’re okay.”

It took a while before the crying slowed. Even then, Shinsou didn’t pull away just sat there, exhausted, breathing uneven, clinging to what little stability he had left. “Can you stand?” Aizawa asked after a moment. A small nod. “Alright. We’re not staying here.” He helped Shinsou up carefully, keeping a hand near him in case he stumbled which he did, slightly. Aizawa steadied him immediately.

“Come on. You’re coming home with me.” The word home made Shinsou freeze for half a second but Aizawa didn’t miss it. “My place,” he corrected quietly. That seemed to help. Before they left, Aizawa pulled out his phone, typing quickly. ‘Shinsou is coming over.’ Sent to Hizashi. Then he grabbed another blanket, wrapping it more securely around Shinsou before guiding him out into the hallway and into the rain again this time with someone beside him.

By the time they reached the apartment, Shinsou was barely holding himself up, he was half asleep and tear stained while Aizawa got the door open quickly, ushering him inside, away from the cold. “Sit,” he said, guiding him to the couch. Warmth hit almost instantly. And with it everything else. The warm lamps and lights cascading around the apartment. The cat doors, cat toys and cat food bags around the house. The messy pantry that was covered in unicorn stickers.

Now that he wasn’t running anymore, the adrenaline was gone. The pain came back harder. The exhaustion. The shaking. “…They-” Shinsou started, voice hoarse, staring down at his hands. “My parents..hit me.” Aizawa’s expression didn’t change much but something in his eyes did. Something sharper. Colder.

“…I figured,” he said quietly. “You don’t have to explain right now.” But Shinsou shook his head. “I didn’t get into the hero course,” he continued, words tumbling out unevenly. “They said I-wasted their money and” His breath caught again. “I tried,” he whispered. “I really tried.” “I know,” Aizawa said immediately. Too quickly for it to be anything but certain.

Shinsou looked up, just slightly and that’s when Aizawa noticed it. “…You’re still bleeding.” It had started again. Slower this time, but enough. Aizawa moved without hesitation, grabbing a towel and a basic first aid kit, kneeling in front of him again. “Hold still.” Shinsou flinched slightly when the towel touched his face but Aizawa’s movements were careful. Gentle.

“You’re alright,” he repeated quietly. “You’re safe here.” The words were steady. Certain and maybe for once Shinsou would feel it.

The apartment was quiet except for the soft hum of the heater and the steady patter of rain against the windows. Shinsou sat curled slightly into himself on the couch, the blanket wrapped tight around his shoulders, damp hair clinging to his face. Aizawa knelt in front of him, one hand steady as he finished cleaning the last of the blood from his nose movements careful gentle in a way that didn’t feel fragile, just… safe.

“You’re alright,” Aizawa murmured again, more to ground him than anything. Shinsou nodded faintly, though his breathing was still uneven. The hall way light went on and a very exhausted looking Hizashi appeared. “Shouta, i-“ Hizashi stepped into the room and stopped. His eyes flicked from Aizawa, kneeling on the floor, to Shinsou on the couch wrapped in blankets, bruised, exhausted, clearly not okay.

There was a pause. A long one.

“…I’ll be in the study,” Hizashi said quietly. And then he turned around and walked right back out. No questions. No noise. Just space. Aizawa didn’t even look up, but there was the faintest shift in his shoulders acknowledging it. Shinsou blinked, confused, still a little out of it. “…Was that-” “Yeah,” Aizawa said simply. “Don’t worry about it.” He stood, moving to sit beside him instead, not too close just enough to be there.

“Have you eaten?” he asked after a moment. Shinsou hesitated. Then shook his head. “No.” Aizawa hummed quietly, already pulling his phone out. “Figures.” He didn’t make a big deal out of it. Didn’t sigh, didn’t lecture just opened an app and scrolled for a second. “Any allergies?” Shinsou shook his head again. “Good.” Aizawa tapped a few times. “Let’s order…Japanese curry. Easy to eat.”

There was something grounding about how normal he made it sound. “And tea,” he added. Shinsou blinked, watching him. “…You don’t have to-” “I know, I haven’t had dinner yet either.” Aizawa said simply. The room fell quiet again, but it wasn’t as heavy this time. Shinsou shifted slightly under the blanket, and that’s when he noticed it.

A faint sound. A soft ‘thump’… then another. His eyes flicked toward the hallway. “Do you have a cat?” he asked quietly. Aizawa didn’t even look surprised. “Yeah.” Right on cue, a slow, heavy presence padded into the room. A very round, very fluffy cat. Mochi. He stopped halfway, blinking up at Shinsou like he was assessing him then, with absolutely no hesitation, continued forward and jumped up onto the couch beside him with a soft oof.

Shinsou blinked twice, Mochi turned once, twice, then flopped right against his side like he’d decided he belonged there. “…Oh,” Shinsou breathed. Carefully like he thought he might disappear he reached out and rested a hand on his fur. He could feel a slow heartbeat, the drums of an inner purr. Mochi immediately started purring. Something in Shinsou’s shoulders dropped. “He’s nice,” he said, voice quieter now but calmer.

Aizawa glanced over. “He likes you.” Shinsou startled slightly, but Mochi didn’t move so he didn’t either. Shinsou looked to the hall way then looked back at Aizawa, hesitation flickering across his face. “…I didn’t know you were… married,” he admitted. Aizawa didn’t react much but he just leaned back slightly, arms resting loosely. “We keep it quiet.”

Shinsou nodded slowly, fingers still absentmindedly brushing through Mochi’s fur. There was another small pause. Then Aizawa spoke again, quieter this time. “I’ve got two kids.” Shinsou blinked, clearly not expecting that. “You do?” “Yeah.” Aizawa’s gaze flicked toward the hallway for a second, like he could see them even when they weren’t there. “Eri. She’s four.”

Shinsou’s expression softened slightly at that. “And (Y/N) is Fifteen.” That caught him more off guard. “Oh.” “Yeah,” Aizawa said, like it wasn’t a big deal. “You’ll probably meet them eventually.” Shinsou nodded slowly again, still processing. But now he had the warmth of the blanket, the steady sound of rain, the quiet clinking of traffic below and Mochi purring loudly against his side.

Shinsou stayed quiet for a while, fingers absentmindedly combing through Mochi’s soft fur as his purring filled the space between them. The warmth, the quiet, the steady presence of someone not yelling at him it all felt… unreal. But his mind hadn’t stopped turning. “What are they like?” he asked suddenly, voice softer now, hesitant. “Your kids.”

Aizawa glanced at him briefly, like he was deciding how much to say. “Depends which one,” he muttered. Shinsou huffed faintly at that, the smallest hint of something almost normal slipping through. “Both.” Aizawa leaned back slightly into the couch, arms loosely crossed, eyes half-lidded like always but there was something calmer about him now.

“Eri’s the youngest,” he started. Shinsou nodded, listening closely. “Her quirk is called Rewind,” Aizawa continued, voice quieter now. “She can reverse a person’s body to a previous state.” Shinsou’s hand stilled slightly in Mochi’s fur. “…That sounds… really strong.” “It is,” Aizawa said simply. “It’s also dangerous. She can’t fully control it yet.” His tone didn’t change much but there was something heavier underneath it. Careful. Protective.

Shinsou nodded slowly. “So… she needs training too?” “Yeah.” Aizawa didn’t elaborate but he didn’t need to. Shinsou looked down for a second, then back up. “And (Y/N)?” That got a different reaction. Aizawa exhaled lightly through his nose, something almost like quiet amusement flickering across his face. “He’s fifteen,” he said. “And he’s got a cat-type quirk.” Shinsou blinked. “…Like-” “Ears. Tail. Enhanced reflexes. Night vision,” Aizawa listed plainly. “Claws when he wants them.”

Shinsou’s eyes flicked down to Mochi, then back up. “That’s kinda cool.” “Yeah,” Aizawa admitted. “Don’t tell him I said that.” Shinsou let out the faintest breath of a laugh barely there, but real. “What’s he like?” he asked. Aizawa didn’t even hesitate this time. “Grumpy.” Shinsou snorted quietly. “Constantly,” Aizawa added. “Bad attitude. Acts like he hates everything.” “Does he?” Shinsou asked. Aizawa shook his head slightly. “No.”

There was a brief pause. “He just pretends to.” Shinsou went quiet again, something about that answer sticking with him. Mochi shifted beside him, pressing closer, her purring louder now. Without thinking, Shinsou rested his head back against the couch, fingers still tangled in her fur. “He sounds” he hesitated, searching for the word. “Like someone I’d get along with.”

Aizawa glanced at him. “Probably.” The room settled into a softer silence after that, the rain still falling outside, tea quietly being made in the kitchen, and the weight in Shinsou’s chest just a little bit lighter than before.

The food arrived not long after. Aizawa brought it in quietly, setting everything down on the table like he didn’t want to startle anything fragile. Warm containers, the smell of Japanese curry filling the room almost instantly, rich, comforting and grounding in a way Shinsou hadn’t realised he needed. “Eat,” Aizawa said simply, handing him a spoon.

Shinsou hesitated for half a second like he wasn’t sure he was allowed to but then nodded, shifting forward slightly on the couch. Mochi grumbled at the movement but stayed pressed against his side. The first bite was almost overwhelming. His stomach twisted like it didn’t know what to do with it after everything, but he kept eating anyway slow at first, then a little faster.

Aizawa ate beside him steady, like this was normal. Like Shinsou being there bruised, exhausted, wrapped in a blanket was something that could just fit into their night. “It’s good,” Shinsou muttered after a while, almost like he felt he had to say it. It wasn’t a long meal. Shinsou slowed down halfway through, exhaustion catching up to him again, the warmth making his eyelids heavy.

Aizawa noticed immediately. “You’re done,” he said, taking the container before Shinsou could argue. “I can-” “No,” Aizawa cut in, not harsh just certain. “You’re going to sleep.” Shinsou didn’t fight it. He didn’t have the energy to.

The spare room was simple. Clean. A little unused but not unwelcoming. Aizawa handed him a dry shirt and sweatpants. “Change. There’s a towel in the bathroom.” Shinsou nodded, moving slower now, every step heavy. By the time he came back out, hair still damp, clothes slightly too big, he looked smaller somehow. Aizawa had already pulled back the blankets.

“Get in.” Shinsou did, hesitating only slightly before slipping under them. The bed felt like home although it wasn’t his to call home. He felt safe here, like nothing bad could happen ever. “Thank you,” he mumbled, voice barely audible. Aizawa paused by the door, watching him for a second. “Go to sleep, Shinsou.” For the first night in a few days he slept. A soundless sleep.

The apartment fell quiet again. Rain still tapping against the windows. The soft hum of everything settling. Hizashi leaned against the doorway, arms loosely crossed. “Is he okay?” Aizawa stepped out, closing the door gently behind him. “He will be.” Hizashi studied him for a second longer, then sighed softly. “You’re not sleeping, are you?” Aizawa didn’t answer. “Yeah,” Hizashi muttered. “Thought so.”

“I’ll be in the living room.” “Mm.” Hizashi didn’t stop him. The glow of the laptop lit up the dim room. Aizawa sat at the table, shoulders slightly hunched, eyes sharper now focused. The email had been open for a while before he started typing. He explained everything that needed to be said and nothing that didn’t. That Shinsou’s home situation was no longer stable. That his parents would no longer be responsible for his schooling. That, effective immediately, Shinsou would not be returning to that environment.

Aizawa’s fingers hovered over the keyboard for just a second. Then continued. That financial responsibility would be transferred. That arrangements would be handled personally. That Hitoshi Shinsou would continue his education without interruption. Aizawa rubbed his eyes and added the final line. That Shinsou would be residing under his care moving forward. Simple. Final. Non-negotiable. Aizawa read over it once. Twice. Then hit send.

He sat there in the whispers of the rain, Hizashi padded in quietly, setting a fresh cup of tea beside him without a word before leaning against the counter.“…You’re serious,” he said after a moment. Aizawa didn’t look up. “Yeah.” “We’re doing this?” Aizawa finally glanced over. “He’s not going back there.” It wasn’t said loudly. It didn’t need to be. Hizashi held his gaze for a second then exhaled softly, something warm and certain settling into his expression.

“Yeah,” he said. “Okay.” Another pause. Then, lighter “Guess we’ve got another kid, huh?” Aizawa huffed quietly, the faintest hint of something almost tired-soft crossing his face. “Looks like it.” Down the hall, the spare room stayed quiet. For the first time in a long time Shinsou slept without fear of what would happen when he woke up.