Welcome to Hero School, Iruma-Kun!

by rockpunkprincess

Summary:

a coffee, a hectic morning and a (not) demon.

Notes:

The story is ongoing idk how to edit that eh

Chapter 1

"What the Actual Fuck, Hizashi?"

 

 

The morning was supposed to be as normal as can be.

 

 

Shouta Aizawa expected to wake up to the scent of coffee and the distant sound of his husband's off-key singing in the kitchen. He expected to be force-fed breakfast before he even had the chance to sit down properly. He expected Hizashi to drag him out of bed before his alarm even had the chance to alarm clock.

 

 

Instead—

 

 

His alarm had blared obnoxiously for a full minute before he groggily reached over to shut it off. No scent of coffee. No annoying voice calling him Shou, get your ass up, you damn hibernating cat! Just... silence.

 

 

That alone was enough to put him on edge. Worming himself out of his sleeping bag, he trudged toward the living room, rubbing the sleep from his eyes.

 

 

What he saw made him stop dead in his tracks.

 

"Hizashi," he called, voice dangerously calm.

 

 

His husband was sprawled across the floor, painstakingly drawing something onto the wooden boards. Intricate lines and symbols looped together, forming what could only be described as an occult summoning circle.

 

Discarded scrolls littered the room, and in the middle of it all, Hizashi sat cross-legged, humming to himself as he dipped his brush into a container of deep red ink—

 

Wait. Aizawa sniffed the air, his stomach sinking at the distinct metallic tang.

 

"...Is this blood?" he asked, his voice eerily level. Lifting the container to his nose, the scent of rust and iron hit him full force. "What the fuck, Hizashi. This is blood."

 

 

His husband—his absolute menace of a fully grown adult husband— beamed at him like a child caught stealing from the cookie jar.

 

"Yup!" Hizashi chirped. "Not mine, though!"

 

"That's not the point!" Aizawa pinched the bridge of his nose, already feeling a migraine creeping in. His morning routine had derailed so catastrophically he wasn't even sure if he was still awake. Maybe this was some fever dream caused by his caffeine withdrawal.

 

 

He cautiously stepped closer, avoiding the symbols drawn onto the floor. His eyes landed on a thick-ass brown tome, nearly two feet tall, sitting open near the center of the summoning circle.

 

The cover read in what he could only describe as suspiciously unhinged handwriting: "How to Summon the One Who Will Grant All Your Wishes!"

 

 

His stomach dropped.

 

"What. The. Fuck."

"Language, honey."

Aizawa whirled around to glare at his husband. "Hizashi. Why the fuck are you trying to summon a demon in our living room?!" Hizashi blinked at him like he was the idiot in this situation.

 

"Demon? Nah, babe, I'm summoning the one who can solve all our problems." he said while quoting in the air.

 

"That sounds like a demon to me."

"Nope! This is different!" Hizashi waved a hand dismissively before pointing dramatically at the open tome.

 

"The book says this person can grant any wish, no contracts, no soul-sucking nonsense, just straight-up wish fulfillment! It's foolproof!"

 

"Foolproof," Aizawa repeated blankly.

 

"Mhmm!" His eye twitched. He turned around, walked straight into the kitchen, and grabbed every type of coffee within reach.

 

Because if he was going to deal with this, he won't deal with this sober, he needed his regulated substance. As the coffee brewed, he pulled out his phone, checking for an update from the orphanage.

 

Still nothing.

 

He exhaled slowly, rubbing a hand over his face.

 

He took a sip. Good.

 

Another sip. Better.

 

Another— A cold breeze slithered through the apartment.

 

Aizawa stiffened. The wind picked up, growing stronger by the second.

 

Then—

 

The ground trembled. Aizawa barely had time to put down his coffee before the tremors knocked the cup right out of his hands. The mug shattered against the floor.

 

"WHAT THE FUCK IS HAPPENING IN THERE, 'ZASHI?!" he shouted, grabbing his capture weapon from the couch as he rushed back into the living room.

 

The scene that greeted him made his blood turn ice cold.

 

The summoning circle glowed. An ominous golden light pulsed from the floor, tendrils of energy crackling through the air. The symbols Hizashi had drawn in blood burned bright, twisting unnaturally, shifting—

 

And in the center of it all, something was forming.

 

A silhouette.

 

A humanoid shape slowly materialized from the blinding light, the glow outlining their figure. Aizawa's instincts screamed at him to move, to grab Hizashi and get the hell out of there.

 

"HOLY SHIT, SHOU, IT WORKED!" Hizashi cheered.

 

Aizawa barely had time to yank his dumbass husband behind him before the light exploded— And then, just like that, it was over. The energy dissipated. The room fell silent.

 

And standing right in front of them was— A kid.

 

A very confused, very normal-looking blue-haired kid.

 

The boy blinked at them. Aizawa tightened his grip on his capture weapon. The kid took a step back. Both of them spoke at the same time.

 

"Who are you?" Aizawa demanded.

 

"Where am I?" the boy asked, voice laced with panic.

 

Hizashi? Beaming like an idiot.

 

"MR. GENIE, PLEASE GRANT ME A WISH!" The kid visibly paled.

 

"U-umm, sirs," he stammered, hands raised in surrender, "I think there's been a mistake! I-I'm not a genie or whatever! I'm just a kid on my way to school!" His voice rose in distress. "I don't even know how I got here! One second I was walking, and then—BAM, I fell through the ground, and now I'm here!"

 

Aizawa narrowed his eyes, watching the way the kid's breathing grew more erratic. His hands trembled. He was panicking.

 

Shit.

 

He slowly lowered his weapon.

 

"Okay. Okay." Aizawa spoke gently. "Calm down, kid. We're not going to hurt you."

 

The boy nodded rapidly, chest rising and falling too fast. "Good. Now, inhale," Aizawa said, voice steady, "exhale."

 

The kid tried to follow his instructions. His breath hitched, then evened out slightly. "Inhale," Aizawa repeated, "exhale. Focus on my voice. You're safe."

 

The boy took another shaky breath and nodded again.

 

 

His fingers curled into fists at his sides, but the tension in his shoulders slowly loosened. Aizawa exhaled through his nose. Crisis averted—for now.

 

"Now, let's start from the beginning," he said, rubbing his temples. "Who are you?"

 

The boy straightened up as much as he could. "M-My name is Iruma. Suzuki Iruma. I live with my grandpa and Opera-san, and I have two best friends, and I really need to get to school or else I'll be late for class and Kalego-sensei will kill me!"

 

Aizawa frowned. "Right. And where exactly is your school?" Iruma opened his mouth—then promptly froze. His eyes went impossibly wide, his face draining of all color.

 

"Uh," he squeaked, voice suddenly very, very small. Aizawa's stomach dropped.

 

"...Kid. Where the hell were you before you got here?" Iruma swallowed thickly.

 

"Um. So... about that..." He laughed nervously. "I'm... pretty sure I was in Hell."

Chapter 2

Silence.

Aizawa stared at the kid.

Hizashi stared at the kid.

The kid—Iruma, apparently—stared back, shifting awkwardly under their gaze.

 

"...Sorry, I think I misheard you," Aizawa said, pinching the bridge of his nose. "Where did you say you were?"

 

Iruma scratched his cheek. "Um. You know. Hell."

 

Silence.

 

"...Shou?" Hizashi finally said.

"Yeah?"

"I think I actually did summon a demon."

Aizawa inhaled deeply. "Kid, clarify."

 

Iruma flinched at the sharp tone. "W-Well, uh..." He hesitated. "I live in the Netherworld?"

 

Aizawa's eye twitched. "Netherworld?"

 

"Y-Yeah, uh, Hell. But we call it the Netherworld," Iruma corrected, hands waving in a panicked gesture. "I swear I'm not a demon, though! I mean, I—uh—" He suddenly clamped his mouth shut, like he just realized he'd been about to say something really bad.

 

Aizawa narrowed his eyes. "Continue."

 

Iruma swallowed thickly. "I-I'm human."

 

That made Aizawa pause. "You're human."

 

Iruma nodded frantically. "Yep! Totally human! Born and raised! Just a normal guy!"

 

Aizawa exchanged a glance with Hizashi, who looked equally baffled.

 

"...Let me get this straight," Aizawa started, rubbing his temple. "You are a human who somehow ended up in Hell—"

 

"Netherworld."

 

"—Netherworld, and you were just... living there?"

 

Iruma nodded.

 

"And you were on your way to demon school before Hizashi—" He shot his husband a glare. "—dragged you through a goddamn portal into our living room?"

 

"Uh-huh!"

 

Aizawa exhaled very slowly.

 

Then he turned to Hizashi. Hizashi, bless his goddamn heart, had the nerve to look proud of himself.

 

"Shou, babe, honey," he started, grin widening. "I think I actually did it. I summoned the one who can solve all our problems."

 

"He's a teenager, Hizashi," Aizawa deadpanned.

 

"Yeah, but hear me out, Shou—"

 

"No."

 

"But—"

 

"No."

 

Iruma, meanwhile, was shifting uncomfortably. "Um, so, I really appreciate that you guys aren't trying to kill me or anything, but... I kinda need to go back? Like, urgently?"

 

Aizawa shot him a dry look. "Oh, do you now."

 

"Y-Yeah. I mean, my grandpa's gonna freak out if I suddenly go missing, and my teacher's really strict about attendance, and—"

 

The lights flickered.

 

Aizawa's spine went rigid.

 

The temperature in the room dropped several degrees. The faint scent of sulfur curled in the air.

 

Iruma paled.

 

"...Oh no."

 

Aizawa did not like the sound of that. "What do you mean, 'oh no'?"

 

Iruma looked at him with wide, panicked eyes. "U-Um, so, the thing about the Netherworld is... teleportation magic isn't exactly subtle."

 

The ground rumbled. Aizawa cursed, instantly reaching for his capture weapon. "Hizashi—"

 

"Already on it, babe!" Hizashi immediately yanked Iruma to his side, shielding him as the entire house shook.

 

Aizawa braced himself as a massive tear split the air in the middle of their living room.

 

The portal widened, crimson lightning crackling around its edges—

 

And then, from the other side, a towering figure stepped through.

 

A seven-foot-tall, sharply dressed butler emerged, his presence impossibly heavy. His dark, feline-like eyes zeroed in on Iruma in an instant.

 

Iruma froze.

 

"Opera-san," he squeaked.

 

Aizawa had faced villains, monsters, and eldritch horrors before, but something about this... Opera person sent every single one of his instincts into overdrive.

 

The butler took a slow step forward.

 

"Young Master Iruma," they said, voice smooth but dangerously unimpressed.

 

Iruma let out a high-pitched laugh. "H-Hi! Uh, I can explain?"

 

Opera smiled.

 

It was not a friendly smile.

 

Aizawa tightened his grip on his weapon.

 

Shit.

 

Things just got a whole lot worse.

 

Aizawa had seen some shit in his life.

 

But this?

 

This was too much.

 

The moment the strange, feline-like demon— Opera, as Iruma had called them—tried to step forward, something in the air cracked.

 

A deep, resonating shudder ran through the walls.

 

Aizawa felt it in his bones, like the universe itself had been jolted awake.

 

Opera froze.

 

For a split second, the air bent around them—distorting like a heatwave, warping the very space they occupied.

 

Then—

 

CRACK.

 

A jagged rift split open behind them—glowing, pulsing, wrong. It was not a portal. It was not magic.

 

It was reality rejecting their existence.

 

The house groaned, the very fabric of the world straining to keep balance.

 

Then—as fast as it appeared—

The crack sealed itself shut.

The world snapped back into place.

 

And Opera was still standing in Aizawa's living room.

 

Only now, they were frowning.

 

"..I see."

 

Aizawa slowly lowered his stance. "The hell was that?"

 

Opera clicked their tongue, looking more annoyed than anything. "A problem."

 

Iruma paled. "Opera...?"

 

The demon exhaled sharply, shaking their head. "This is unfortunate."

 

"What's unfortunate?" Hizashi piped up. "Because from where I'm standing, it looked like you were about to rip a hole in reality."

 

Opera gave him a flat look. "Not entirely inaccurate."

 

Iruma gulped. "T-Then... does that mean...?"

 

Opera turned to him, their red, slitted eyes gleaming sharper than before. "Yes."

 

Then, with the grave finality of a death sentence, they said:

"You cannot go back."

 

Silence.

 

Pure, deafening silence.

 

Iruma's breath hitched. "W-What?"

 

Opera's expression remained unreadable. "You cannot go back to the Netherworld."

 

"What do you mean he can't go back?" Aizawa cut in. "Didn't you just try to open a way?"

 

Opera narrowed their eyes. "I attempted to return through the natural order of things. However,"they gestured vaguely at the space around them, "this world rejects my presence."

 

Aizawa thought back to the way reality had fractured around Opera. "Because you're too strong," he realized.

 

Opera nodded. "Indeed. Had I forced my way through, it would have disrupted the balance of this realm."

 

Hizashi whistled. "Damn. That strong, huh?"

 

Opera ignored him. "The rift closing so quickly is proof of that. The world is resisting. It is ensuring I do not linger."

 

Iruma looked distressed. "But what about me?" he asked, voice small. "I'm just human—shouldn't the Netherworld let me in?"

 

Opera was silent for a long moment.

 

Then they said, "Perhaps it would have, if you had crossed over naturally. But you were summoned, Young Master. And if I am not mistaken—"

 

They turned to Hizashi.

 

"—this was not a simple summoning, was it?"

 

Hizashi scratched the back of his head. "Uh... depends on what you define as 'simple'."

 

"I define it as 'a spell that doesn't warp space-time.'"

 

"Then, uh, nope?"

 

Aizawa resisted the urge to smack his husband. "You absolute—"

 

"I thought it would just bring a normal demon,"Hizashi hurriedly defended. "Not a kid, okay? I didn't mean for this!"

 

"And yet, here we are," Opera deadpanned.

 

Aizawa rubbed his temples, already exhausted. "So what you're saying is, the summoning fucked with his connection to the Netherworld?"

 

"Precisely," Opera confirmed. "The magic did not just call him here—it ripped him away. And in doing so, it severed the path that allows him to return."

 

Iruma staggered. "So I... I really can't go home?"

 

Opera's expression softened. "Not by conventional means," they admitted. "Not yet."

 

Iruma's hands clenched at his sides. "But—Grandpa—"

 

"He will be searching for you," Opera assured him. "Do not doubt that."

 

Iruma looked down, teeth biting into his lip.

 

Aizawa exchanged a glance with Hizashi.

 

Neither of them had expected this.

 

They were just two guys trying to adopt a kid. And now they were apparently harboring a lost human prince from Hell.

 

Aizawa let out a long, suffering sigh. "So what now?"

 

Opera tilted their head. "Now?"

 

Then, very seriously, they said—

 

"Now, you must take responsibility."

 

Aizawa blinked.

 

Hizashi perked up. "Wait, like—adopt him?”

 

Opera raised an elegant brow. "You were trying to adopt a child, were you not?"

 

Aizawa stared. "That— this isn't the same thing!"

 

"No," Opera agreed. "This is more complicated.”

 

Iruma looked lost. "W-Wait, hold on—"

 

"You are human," Opera continued, "and you are his summoners. That makes you responsible for him."

 

Aizawa pinched the bridge of his nose. "We're responsible for him because my husband is a dumbass."

 

"Correct."

 

Hizashi pouted. "Hey, rude."

 

Opera ignored him and turned to Iruma. "Until we find a way to return you home, Young Master, you must remain here."

 

Iruma's hands shook. "B-But..."

 

Opera crouched down, meeting his gaze with a gentle but firm expression.

 

"Listen to me," they murmured. "You are strong. You have survived much worse. You will endure this as well."

 

Iruma sucked in a shaky breath. Opera straightened, turning back to Aizawa and Hizashi.

 

"I will return once I find a solution." Their voice darkened. "Until then—" their scarlet gaze bore into them, heavy with unspoken threat, "take care of him."

 

Aizawa held their gaze.

 

Then, slowly, he sighed.

 

"Fine."

 

Hizashi grinned. "Guess we got ourselves a kid after all."

 

Iruma let out a weak laugh. "I-I guess so...?"

 

Opera nodded. "Good. Then, for now—"

 

They turned, and in the blink of an eye, vanished.

 

And just like that—

 

Aizawa and Hizashi were left standing in their living room, now the unexpected guardians of a stranded human from hell.

 

"Well," Hizashi clapped his hands. "Guess we should set up a bedroom?"

 

Aizawa groaned. "I need more coffee."

Chapter 3: A New Problem (Or, “What Do We Do With a Kid from Hell?”)

Mornings at the Yamada-Aizawa household had always been relatively quiet. Aizawa was never a morning person, and Hizashi, despite his usual energy, had learned to tone it down before noon.

 

But now, there was an unfamiliar presence in their home.

 

And that presence was currently setting the breakfast table.

 

Aizawa stood in the kitchen doorway, arms crossed, watching as Iruma moved with quiet efficiency. His small hands worked with precision, placing plates and utensils as though it was second nature. He wasn’t just being polite—his movements were careful, practiced.

 

Like he was used to doing this.

 

That fact sat uncomfortably in Aizawa’s chest.

 

Hizashi, seated at the table, finally broke the silence. "Kid, you don't have to do all that, you know."

 

Iruma startled slightly, as if just realizing what he was doing. His fingers twitched, like he’d been caught breaking a rule. "Oh! Uh—sorry. It’s just… a habit."

 

Hizashi chuckled, waving him off. "No big deal, just relax! You’re our guest."

 

Iruma hesitated before nodding, sitting down stiffly at the table.

 

Aizawa took his usual seat across from him, nursing his coffee. The boy reached for a slice of toast but hesitated before taking a bite, his fingers tightening just slightly around the crust. He chewed slowly, carefully.

 

It had been three days.

 

Three days since they’d accidentally summoned a human boy from another dimension. Three days since Opera had arrived, tried to take him home, and promptly realized that reality itself wouldn’t allow it.

 

Which meant Iruma was stuck here.

 

And that presented a problem.

 

The kid had adjusted far too easily. No panic. No tears. No desperate questions about how to get back. Just quiet acceptance.

 

Most kids would be clinging to them for guidance, desperate for reassurance. But Iruma?

 

He just adapted.

 

Like he’d done this before. Like he was used to being shuffled around.

 

Hizashi must have been thinking the same thing, because after a long moment of silence, he sighed and leaned forward, his normally cheerful expression clouded.

 

"Alright, kiddo. We gotta talk."

 

Iruma blinked, pausing mid-chew. "About what?"

 

Hizashi gestured vaguely at him. "You, of course! What are we gonna do with ya?"

 

Iruma tilted his head, confused. "Do with me?"

 

Aizawa sighed, setting his mug down. "You can't just stay cooped up here forever. You’re a kid—you need structure."

 

Iruma blinked at them, something unreadable flickering behind his wide blue eyes. A beat of silence passed before he spoke again, voice quiet.

 

"...I don’t mind staying home."

 

Something about the way he said it—so soft, so matter-of-fact—made Hizashi’s heart twist.

 

"I can help around the house," Iruma added quickly, as if that would make his case stronger. "I can clean, do laundry, organize things—"

 

"Nope, not happening," Hizashi cut in immediately, shaking his head. His voice was firm, but there was something gentle beneath it. "You're not gonna spend your days stuck here doing chores. That’s not healthy, man!"

 

Iruma’s mouth snapped shut. His fingers curled into his lap, shoulders drawing in ever so slightly.

 

Aizawa’s fingers tapped idly against his mug. "...Tell me something, Iruma."

 

Iruma glanced up hesitantly.

 

Aizawa’s gaze was unreadable. "What was your daily life like before you ended up here?"

 

Iruma fidgeted slightly. "Um… well, I’d wake up, get ready, and head to school."

 

Aizawa narrowed his eyes slightly. "You didn’t have any morning responsibilities?"

 

Iruma shook his head. "Opera—our butler—handles all the meals and housework."

 

Aizawa hummed. So he wasn’t used to cooking and cleaning because it was a normal part of his life—he was used to it because it was something he’d had to do before Babyls.

 

Hizashi, meanwhile, latched onto something else entirely.

 

"So you did go to school regularly?"

 

Iruma nodded. "Yes. My teacher’s really strict about attendance…"

 

Aizawa exchanged a glance with Hizashi.

 

That explained a lot.

 

This wasn’t just a kid who happened to be responsible—he had lived in an environment where being capable and adaptable was necessary. He had structure. Expectations. Even now, he was probably waiting for someone to tell him what to do.

 

And that was when the realization hit.

 

Hizashi’s expression changed—his grin turning softer, more thoughtful. His hand rubbed the back of his neck, hesitation flickering across his features.

 

"Shou?"

 

Aizawa sighed. "Don’t say it."

 

"But it’s a great idea—"

 

"Hizashi, no."

 

"Come on, it solves everything!"

 

Iruma looked between them, confused. "Uh…?"

 

Hizashi turned to him, eyes practically sparkling. "Kid, how do you feel about school?"

 

Iruma blinked. "School?"

 

"Yep! As in attending one here!"

 

Iruma paled slightly. "W-Wait, what? But—I don’t have any identification, or records, or—"

 

"That’s the easy part," Hizashi waved him off. "We’ll talk to Nezu—he loves weird cases like this. We can say you’re an exchange student or something!"

 

Iruma still looked unsure. "B-But I don’t have a Quirk…"

 

Aizawa hummed. "That’s not a dealbreaker. U.A. has plenty of support students who don’t rely on combat abilities."

 

Iruma chewed his lip. "But I don’t even know how this world works…"

 

"That’s the point," Hizashi grinned. "You need to learn, right? So why not do it somewhere where we can actually keep an eye on you?"

 

Iruma hesitated.

 

It did make sense. He had no way of knowing how long he’d be stuck here, and just staying home all day didn’t sit right with him. At Babyls, he at least had a role to fill.

 

If he stayed here with no direction… he might start feeling useless.

 

And he hated that feeling.

 

Hizashi, watching his hesitation, softened. He reached out, ruffling the boy’s hair with an almost too-gentle touch. "You won’t be alone, kid. We’ll be there."

 

There was something wistful in his voice, something almost… longing.

 

Iruma looked up at him, unsure.

 

Hizashi, despite all his energy, had always wanted to be a father. But it wasn’t something he and Aizawa had ever seriously discussed. Their lives were too hectic, too full of responsibilities. Yet, here was this kid—this lost, eager-to-please kid—who had landed right in their laps.

 

And maybe… just maybe… this was something they could do.

 

"...Are you sure I won’t be a bother?" Iruma asked quietly.

 

Aizawa sighed. "Kid, if you were a bother, we’d have said so already."

 

Hizashi nodded, smiling. "Yeah, buddy! Besides, you didn’t ask for any of this—we’re just trying to make it work."

 

Iruma still seemed uncertain, but a small part of him… felt relieved.

 

Maybe—just maybe—this wouldn’t be so bad.

 

"...Alright," he finally said. "I’ll try."

 

Hizashi beamed, ruffling his hair again. "That’s the spirit, kiddo! Welcome to U.A.!"

 

Aizawa sighed, sipping his coffee.

 

This was going to be a headache.

Notes:

Sorry if the spacings a little bit wonky, i’m typing on my phone and it’s hella difficult 😭