Chapter Text
The room had finally started to calm down when Osamu Dazai's voice broke through, softer than usual.
“…There’s something we need to discuss.”
His tone was different, and that subtle shift caught Shota Aizawa’s attention immediately.
“…Go on,” Aizawa prompted, curious.
Dazai cast a quick glance at Chuuya Nakahara. Chuuya remained silent, offering no objections, so Dazai pressed on.
“…Why do quirks here… change people?” he inquired. “Physically.”
A moment of silence hung in the air.
“In Yokohama,” he added, “abilities don’t do that.”
His words resonated in the room. Hawks tilted his head, intrigued, while Nezu's gaze sharpened, reflecting a mix of thoughtfulness and understanding.
Aizawa was the first to respond.
“…Because quirks aren’t external,” he explained. “They’re part of the body.”
Dazai’s eyes narrowed slightly, curiosity piqued. “Define ‘part.’”
Nezu interjected, his voice steady and precise.
“In our world, quirks are genetic,” he clarified. “They’re inherited, biologically expressed—woven into a person’s physiology from birth.”
Chuuya frowned, a hint of confusion in his expression. “So… it’s not something separate from them?”
“Correct,” Nezu affirmed. “A quirk is not an *addition* to the body—it is, in essence, the body itself.”
Hawks nodded, adding with a casual air, “That’s why you see physical traits—wings, extra limbs, unique eyes—whatever matches the ability.”
He shrugged lightly, his own wings shifting behind him. “It’s all interconnected.”
Dazai absorbed this, his expression inscrutable.
“…So the mutation is a result of the quirk itself?”
“More accurately,” Nezu corrected, “the quirk is the result of the mutation.”
That flipped their understanding upside down.
Chuuya’s gaze sharpened. “So people are born like that?”
“Yes,” Nezu confirmed.
Aizawa crossed his arms, contemplating. “Not all quirks are visible,” he added. “Some are internal, some subtle. But they’re still tied to biology.”
Dazai glanced down at his own hand, a flicker of realization crossing his face.
“…Ours aren’t like that,” he said. “Abilities in Yokohama don’t alter the body.”
Nezu nodded thoughtfully. “Which suggests a fundamentally different origin,” he mused. “Your abilities may not be genetic in the same way, or may operate through an external or metaphysical mechanism rather than biological mutation.”
Chuuya clicked his tongue in annoyance. “Great. So we’re the odd ones here.”
Hawks smirked, leaning back with an air of amusement. “You say that like we didn’t already notice.”
“Shut up.”
Aizawa chose to focus on the more pressing matter at hand. “…It also means your abilities may not follow the same rules,” he said. “Which makes them harder to predict.”
Dazai offered a faint smile. “That’s usually how we operate.”
Nezu’s gaze lingered on both of them, a hint of understanding in his eyes. “Different systems,” he said softly, “but not incompatible.”
Chuuya adjusted his hold on Shuji, the baby nestled in his arms. “…As long as it doesn’t affect him,” he muttered.
Aizawa glanced at the baby, then back at them. “…We’ll make sure it doesn’t,” he assured.
Dazai didn’t respond immediately, but he didn’t argue either. For the first time, they weren’t just learning about this world; they were beginning to understand where they fit within it.
The conversation settled into a quiet understanding. After a moment, Nezu hopped lightly down from his spot. Aizawa followed suit, straightening from where he had been leaning.
“Well,” Aizawa said, his tone returning to its usual calm bluntness, “that covers what we needed.”
His gaze flicked between Osamu Dazai and Chuuya Nakahara. “I’ll meet you in class.”
Chuuya nodded, a small acknowledgment. “…Yeah.”
Aizawa then turned his attention to Shuji, still securely in Chuuya’s arms. “Hawks will be here while you’re in school,” he added. “So don’t worry about your kid.”
Hawks flashed an easy grin, leaning back as though he owned the space. “Full-time babysitter,” he declared. “I’ve got it handled.”
Chuuya narrowed his eyes slightly. “…I’m holding you to that.”
“Fair enough.”
Dazai exchanged glances between them, a hint of amusement returning. “…Try not to teach him anything questionable,” he cautioned.
Hawks smirked. “No promises.”
Aizawa sighed quietly, shaking his head. “Ignore him.”
Nezu offered a small, warm smile. “If anything arises, don’t hesitate to contact us,” he said. “You’re not alone in this.”
That sentiment lingered in the air. Chuuya didn’t say anything, but his grip on Shuji relaxed a fraction. Dazai nodded once. “…Got it.”
Aizawa turned toward the door. “Be ready,” he added over his shoulder. “Class doesn’t wait.”
With that, he stepped out, Nezu following closely behind. The door closed softly behind them, and silence returned—but it didn’t feel empty.
Hawks stretched slightly, his wings shifting behind him as he turned back to them. “Well,” he said, “guess it’s just us now.”
Dazai exhaled faintly. “…Looks like it.”
Chuuya glanced down at Shuji, then back up. “…Let’s get ready.”
Because soon enough, they wouldn’t just be survivors anymore; they’d be students.
Preparing for class turned out to be… stranger than either of them had anticipated. Not due to danger. Not because of uncertainty. But for something far simpler.
Clothes.
---
Chuuya Nakahara stood before the mirror, staring at his reflection, feeling an odd disconnect.
“…This feels wrong,” he muttered to himself.
He tugged at the sleeve of his black-and-grey shirt, the fabric looser than what he was accustomed to. The cross design across his chest felt foreign, yet not entirely unpleasant. The long sleeves hung differently, a stark contrast to his usual fitted attire.
He wore black ripped jeans, a chain hanging at his side, and combat boots. It wasn’t bad, just… not him. At least, not the version of himself he recognized.
“…Tch.”
---
Across the room, Osamu Dazai appeared significantly less perturbed, though still out of place in his own right.
He wore a white shirt layered under a soft grey sweater, paired with tan pants and black-and-white sneakers. He glanced down at himself, tilting his head slightly.
“…I look domesticated,” he murmured, a hint of irony in his tone.
Chuuya snorted. “You look normal.”
“That’s worse.”
“Cry about it.”
Dazai offered a faint smile, adjusting his sleeve. “…I suppose it’s a change of pace.”
---
From the main room, Hawks peeked in, taking in the sight of both of them.
There was a brief pause.
Then—
“…Wow.”
Chuuya frowned. “What?”
Hawks grinned. “Didn’t expect you two to clean up this well.”
“Shut up.”
Dazai placed a hand lightly over his chest. “We aim to impress.”
“Mission accomplished,” Hawks replied dryly.
Chuuya rolled his eyes but grabbed his jacket anyway. “…Let’s just go before I change my mind.”
Dazai chuckled softly. “Too late. You’re already part of society now.”
“Don’t remind me.”
---
In the background, Shuji made a small, content sound, observing the activity around him. Chuuya’s attention flicked to him, his expression softening just a fraction.
“…We’ll be back soon,” he murmured, more to himself than anyone else.
Dazai noticed but chose not to comment. Instead, he stepped toward the door, glancing back once. “…Ready?”
Chuuya took a deep breath. Then he nodded. “…Yeah.”
And just like that—dressed in clothes that didn’t quite feel like theirs yet—they stepped out to face something entirely new.
The hallway outside Class 1-A buzzed with energy, louder than anything they had experienced since their arrival.
Voices, laughter, movement.
Normal.
Chuuya stood before the door for a moment, hand hovering before finally knocking.
A beat passed.
From inside—
“Come in.”
It was Shota Aizawa.
Chuuya glanced at Osamu Dazai, who offered a faint, encouraging smile. “After you.”
“…Tch.”
Chuuya pushed the door open.
---
The classroom stilled almost instantly, dozens of eyes turning toward them.
Students.
Some looked completely ordinary.
Others—
Not.
Horns, tails, unusual eyes, skin tones that defied anything Chuuya had seen before. Physical traits that were clearly a part of them, not mere accessories.
Mutation quirks.
Chuuya’s gaze swept across the room, taking everything in rapidly.
He didn’t stare, but he noticed.
And yes— it felt strange. Not wrong, just… unfamiliar.
Back in Yokohama, abilities didn’t *change* you like that.
For a fleeting moment, something tightened in his chest—
Then his eyes landed on a few students who looked entirely human.
And just like that—the tension eased slightly.
“…Okay,” he muttered under his breath.
Dazai, standing beside him, seemed far less fazed—if anything, mildly intrigued.
“Well,” he murmured, “this is lively.”
---
At the front of the room, Aizawa straightened slightly from his usual slouched position.
“You’re late,” he said flatly.
“Fashionably,” Dazai replied with a hint of mischief.
“Don’t start.”
Aizawa’s gaze moved between them, then toward the class.
“These are the two new students I mentioned.”
A low murmur spread through the room—curiosity, whispers.
Aizawa didn’t allow it to build.
“Introduce yourselves,” he instructed. “Names. Abilities. Full explanation.”
That snapped Chuuya fully out of his thoughts.
“…Right.”
He stepped forward slightly, one hand sliding into his pocket.
The room quieted once more, all eyes on him.
Chuuya exhaled once, steadying himself.
Then—
“Chuuya Nakahara,” but please call me Chuuya I don't like my last name. he announced, without hesitation.
“My ability is called *Upon the Tainted Sorrow*.”
A few students leaned forward, captivated.
“I control gravity,” he continued bluntly. “Anything within my range or line of sight—I can manipulate it. Increase it, decrease it, crush things with it, move myself—whatever.”
The room fell silent, the weight of his words sinking in.
That wasn’t a small ability.
Chuuya didn’t sugarcoat it.
“There’s also a state called *Corruption*,” he added, his voice taking on a sharper edge. “It boosts my power way past normal. I can create gravitational singularities—basically miniature black holes.”
A few audible reactions filled the room this time, a mix of awe and alarm.
“…But,” he continued, his tone firm, “I lose control. Completely. If I go into it, I don’t stop until someone stops me—or I die.”
Silence enveloped them, heavy and palpable.
Chuuya gestured slightly toward Dazai. “He’s the only one who can shut it down.”
Attention shifted instantly to Osamu Dazai.
Dazai stepped forward, his demeanor relaxed.
“Osamu Dazai,” he introduced himself smoothly, a faint smile gracing his lips.
“My ability is called *No Longer Human*.”
He raised a hand just enough to catch everyone’s attention. “When I make contact, I can nullify abilities. Completely.” There was a brief pause before he continued, “And the thing is, it’s always active. There’s no off switch.”
The atmosphere in the room shifted, plunging into a profound silence.
Aizawa observed his class with keen eyes, taking in their varied reactions.
Shock flickered across some faces.
Interest sparked in others.
Caution settled in like an uninvited guest.
Dazai casually tucked his hands into his pockets, a playful smirk dancing on his lips. “Just a heads up—try not to lean too heavily on your quirks around me. You might find it a bit disappointing.” His lighthearted remark eased the tension, if only slightly.
Aizawa let out a slow breath. “Alright,” he said, his voice steady. “Please take your seats.” Chuuya scanned the room once more, still acutely aware of the differences and adjusting to them,
but the tightness in his shoulders had eased. Dazai strode forward with an air of confidence, as if he had always belonged there. In that moment, they seamlessly transitioned into being part of Class 1-A.
The hush that enveloped the room following their introductions was short-lived.
Almost instantly, a hand shot up.
With messy green hair and wide, analytical eyes, Izuku Midoriya leaned forward, clearly grappling with the flood of information.
“Um—Aizawa-sensei?” he began, his voice a mix of curiosity and concern. “Shouldn’t we refer to them as *quirks*? And what’s with the term *abilities*? Why are they using different names?”
A few classmates nodded in agreement, murmuring their own questions.
Suddenly, a sharp voice sliced through the air.
“Tch. Who cares?”
Katsuki Bakugo reclined in his seat, a scowl etched on his face.
“If they’re strong, that’s all that matters,” he declared, his gaze challenging as it flicked toward Chuuya and Dazai. “The name doesn’t change anything.”
Aizawa appeared unfazed by the interruption.
“Bakugo,” Shota Aizawa stated flatly, “please sit down and refrain from disrupting the class.”
“Tch.”
Bakugo relented, though his irritation lingered.
Aizawa turned his attention back to Midoriya.
“It’s a valid question,” he acknowledged, inviting the class to listen closely.
As the classroom quieted again, Aizawa explained, “Their terminology differs because they come from a different system. From where they are from, powers are called *abilities*, not quirks.”
Midoriya’s eyes sparkled with excitement, his mind racing ahead.
“So their powers aren’t genetic?” he asked eagerly.
“Unknown,” Aizawa replied. “However, according to what we know, they don’t function like quirks do.”
A brief pause hung in the air.
“They don’t cause physical mutations,” he elaborated, scanning the room to ensure everyone was following. “And they seem to operate under different rules.”
The class buzzed with contemplation.
Midoriya muttered to himself, clearly deep in thought.
“Different origins… different limitations… maybe external vs. internal activation…”
Bakugo rolled his eyes, exasperated. “There he goes again.”
Nearby, Dazai tilted his head, amusement flickering in his expression.
“…He’s interesting,” he remarked quietly.
Chuuya shrugged slightly. “He’s loud in a different way,” he replied, a hint of amusement in his voice.
Aizawa continued, his tone steady. “For now, you’ll approach their abilities as you do with quirks—in terms of training and control. But remember, what applies to you may not apply to them.”
That seemed to settle the matter.
Mostly.
Bakugo still appeared unimpressed, though a spark of interest shone in his eyes now.
Midoriya, on the other hand, looked like he had a hundred questions dancing on the tip of his tongue.
And the rest of the class?
Curiosity filled the air.
Aizawa glanced back at Chuuya and Dazai.
“Please take your seats,” he reiterated.
This time—
there were no interruptions.
Yet the attention on them?
That was far from fading.
Aizawa surveyed the room, ensuring everyone was settled.
“Since we have new students,” Shota Aizawa announced, “today’s lesson will be different.”
A few students perked up, intrigued.
“We’ll be delving into the *Tripartite Framework* in Yokohama.”
That revelation sparked immediate reactions—confusion, curiosity, and interest rippled through the room.
Aizawa’s gaze swept across the class.
“What do you know about Yokohama?”
Before he could finish, two hands shot up.
Quickly.
Izuku Midoriya.
And Shoto Todoroki.
Aizawa pointed at Midoriya.
“Midoriya.”
Midoriya straightened, his mind racing.
“Yokohama is known as a high-risk zone with a concentration of normal people,” he explained, speaking rapidly but clearly. “There’s limited official hero presence compared to other regions, and a lot of underground activity—crime organizations, independent groups…and this is my guess but since Chuuya and Dazai are here they must be from Yokohama meaning that some percentage of people there have abilities like them”
He paused, searching for the right words.
“…It’s not governed like most areas of hero society.”
Aizawa nodded approvingly. “Good.”
Then he turned to Todoroki.
“Todoroki.”
Shoto spoke calmly, weighing his words.
“It’s unstable,” he stated. “Power isn’t centralized. Multiple factions operate there instead of a single authority.”
His eyes flicked momentarily toward Chuuya and Dazai.
“…Which creates conflict.”
Aizawa acknowledged his insight with another nod.
“Correct.”
He shifted slightly, addressing the entire class now.
“Yokohama operates under what’s known as a *Tripartite Framework*,” he clarified. “Three major forces maintain a balance of power.”
Chuuya, leaning back in his seat, muttered under his breath, “Maintain is a strong word.”
Dazai smirked at that, amusement dancing in his eyes.
Aizawa continued, undeterred.
“First,” he began, “law enforcement.”
“Second, organized underground groups.”
A few students exchanged glances, their minds racing with implications.
“Third, independent ability organizations.”
Midoriya was already scribbling notes at a rapid pace.
“So instead of a hero-dominated structure,” Aizawa added, “it’s a balance between opposing forces.”
Bakugo scoffed lightly. “Sounds messy.”
“It is,” Aizawa replied, his tone serious.
Todoroki spoke again, his voice thoughtful.
“What happens if one side collapses?”
Aizawa didn’t respond immediately, his gaze flickering briefly to Chuuya and then to Dazai.
“…Then the balance breaks,” he finally said.
An uneasy silence followed.
Because suddenly—
this wasn’t just a theory anymore.
It was *their* world.
And everyone in that room felt the weight of that realization.
Aizawa stepped closer to the board, ensuring he had the class’s full attention.
“…Listen carefully,” Shota Aizawa instructed. “This isn’t like our system.”
He picked up a marker and wrote three words across the board:
**Day — Twilight — Night**
“This represents the *Tripartite Framework*,” he elaborated. “A three-part balance of power that governs Yokohama.”
A few students leaned forward, intrigued.
“It was designed by Sōseki Natsume,” Aizawa added, “to prevent the city from collapsing under the weight of ability users and conflict.”
Midoriya’s pen flew across his notebook, capturing every detail.
Aizawa pointed to the first word.
---
**“Daytime.”**
“The Special Division for Unusual Powers,” he explained.
“Government-run. They handle legal affairs, administration, and ability-related incidents during the day.”
He paused briefly to let the information sink in.
“Led by Santōka Taneda.”
Todoroki nodded slightly, processing the information. “So they function like law enforcement and regulatory control,” he summarized.
“Correct,” Aizawa affirmed.
---
He tapped the second word.
**“Twilight.”**
“The Armed Detective Agency.”
A few students exchanged intrigued glances.
“They tackle cases too dangerous for standard authorities,” Aizawa clarified. “But unlike underground groups, they operate with a moral code.”
“Led by Yukichi Fukuzawa.”
Midoriya looked up, his curiosity piqued. “So… a middle ground between heroes and vigilantes?”
“Something like that,” Aizawa confirmed.
---
Then—
he pointed to the final word.
**“Night.”**
“The Port Mafia.”
The room shifted slightly at the mere mention of the name.
“Controls the underworld,” Aizawa stated bluntly. “Logistics, illegal operations, black market activity—everything that happens in the shadows.”
A moment of silence followed.
“Led by Ōgai Mori.”
Bakugo scoffed lightly, skepticism lacing his tone. “So you’re saying criminals are part of the system?”
“Yes,” Aizawa replied flatly, silencing him.
---
Aizawa stepped back, allowing the three sections to linger in the air.
“These three groups maintain a balance,” he reiterated. “Not cooperation—*balance*.”
Chuuya leaned back in his chair, arms crossed, a hint of sarcasm in his voice. “...‘Strained’ is putting it lightly.”
Dazai added with a faint smirk, “Functional chaos.”
Aizawa didn’t argue.
“Each controls a part of the day,” he continued. “Daytime, twilight, and nighttime operations.”
Neatly divided.
But fragile.
Todoroki spoke again, his tone serious.
“And if one side breaks the agreement?”
Aizawa’s gaze hardened slightly, the weight of his words heavy in the air.
“…Then the system collapses,” he stated.
Midoriya swallowed hard, connecting the dots in his mind.
“That would mean… constant conflict.”
“Exactly,” Aizawa affirmed, his eyes flicking briefly toward Chuuya and Dazai.
“…This system isn’t about peace,” he added. “It’s about preventing total destruction.”
Silence enveloped the room.
Because suddenly—
Yokohama didn’t just seem like a city.
It felt like a place perpetually on the brink.
And sitting in that classroom—
were two individuals who had navigated the delicate balance of that world.