The alarms still hadn't stopped screaming.Even after the explosion that tore through the central chamber of the Erabus facility, the metallic wail persisted — a chorus of dying machines, groaning steel, and voices that weren't sure if they belonged to ghosts or survivors.
Nagisa staggered forward through the smoke. His breathing was steady, yet his heart was an earthquake under his ribs. The floor hissed beneath him, molten and red with fragments of energy discharge. Sparks fell like glowing rain. Somewhere deeper in the complex, something large was shifting — the heartbeat of Erabus itself.
Hakumura's voice came through the comms, distorted and crackling.
"System's halfway down! I've got to bypass three firewall nodes— this place is running organic encryption. It's breathing, Nagisa— I mean it. The servers are alive from the Erabus energy!"
Nagisa's gaze sharpened. "Alive…" he whispered, stepping past a corridor of shattered glass, each shard catching the burning reflection of the battle that had just ended. Agents lay motionless, their armor still steaming. "Then that means it's feeding on something."
"Yeah," Hakumura's tone dropped. "'Erabus Energy' itself."
The connection fizzled out.
Nagisa exhaled once, grounding himself. He tightened his gloves, checked the knife at his hip — not for killing, but as a reminder of who he once was. The knife was dull, intentionally. He hadn't sharpened it since Koro-sensei's final lesson. He never wanted it to be efficient again.
A low hum rose from the walls, mechanical yet strangely vocal. And then, through the blur of steam, Nagisa saw him.
Dr. Erabus.
Still alive.Still walking.
His pristine lab coat was shredded, his face half-hidden beneath the reflection of his own luminous technology. Wires trailed from his arm into a device that pulsed like a living heart. He looked almost spectral — a being suspended between centuries of guilt and genius.
"You made it farther than I thought," Erabus said, his voice calm, almost paternal. "I suppose that was expected from the student who killed a freak."
Nagisa froze.The words hit him like shrapnel.He didn't correct him — he never did.
Erabus tilted his head, observing him the way a scientist studies a subject. "You still don't understand, do you? All this — the chaos, the pain — is evolution. You began it the moment you pulled that trigger on Koro-sensei."
Nagisa clenched his jaw. "I didn't kill him out of hate. I killed him because I believed in what he taught me — to protect what matters."
Erabus chuckled, the sound low and fractured. "Protect? You murdered the only being who could have saved humanity from itself."
The air around them vibrated. From the walls, the Erabus cores flared to life — hundreds of small, hovering fragments of moonrock fused with biomechanical components. They spun around Erabus, forming a massive orbit of light and sound.
Nagisa's eyes widened. "You… used the moon's debris as a neural field."
"Not used — reborn." Erabus raised his hand, and the fragments glowed brighter. "These stones were touched by the energy of a being beyond our comprehension. I merely harvested their language."
He pressed his palm to himself. The veins beneath his skin glowed blue. "The Erabus Energy you despise — it's not mere science. It's the memory of the explosion that tore the moon apart. The scream of space itself."
Nagisa's grip on his dull knife tightened. "You're losing yourself to it. I can tell."
Erabus smiled faintly. "I already did. A long time ago."
The first clash came without warning.A beam of concentrated Erabus energy ripped through the corridor, slamming into Nagisa's path. He dove aside, the blast tearing through steel and fire alarms. He rolled and landed low, eyes locked on Erabus's shifting silhouette. The scientist moved like a machine, each step powered by magnetic propulsion.
Nagisa darted forward, weaving through the storm of light. He moved with assassin precision — every breath calculated, every dodge flowing like water. His mind recalled old lessons, echoes of a classroom filled with laughter and chalk dust.
"Assassination isn't about killing, it's about understanding."
Koro-sensei's voice whispered through memory, almost like the hum of the Erabus machinery itself.And Nagisa understood.
He closed the distance, striking at Erabus's wrist with his dull blade. Sparks erupted. The scientist staggered back, surprised — not by pain, but by recognition.
"You don't fight to win," Erabus murmured, "you fight to teach."
Nagisa's expression hardened. "You're right. I'm teaching you that your humanity still exists — even now."
Erabus's eyes glimmered, emotion flickering for just a second. Then the madness returned.
"Then learn this lesson yourself!"
He slammed both hands into the floor.The room exploded upward — gravity inverted, pulling debris and fire into the ceiling as the two beings fell upward into a spiraling chamber above. It was a laboratory turned battleground, walls lined with liquid stasis pods containing failed experiments. Some still twitched faintly — hands pressed to glass, faces warped in silent agony.
Nagisa's heart clenched. "You used people—"
"Volunteers!" Erabus shouted, though his voice trembled. "Every one of them believed in my dream — to rebuild the world that your teacher tried to destroyed!"
"Then you don't understand his dream at all," Nagisa said quietly, stepping through the floating rubble. "Koro-sensei didn't destroy the world. He gave it a chance to start again."
The battle intensified.Erabus summoned the fragments of the moonstone into intricate formations — spiraling discs of plasma that fired like sentient bullets. Nagisa's body moved beyond thought, guided by instinct, by years of training under the weight of guilt and growth.
He countered with redirection techniques, using the facility's broken panels to reflect energy beams. He flipped from surface to surface, closing the distance again, until finally he managed to slam his shoulder into Erabus's stomach. Both crashed through a series of floating server tubes, landing hard near the reactor core of the facility.
Nagisa groaned, forcing himself up. Erabus staggered, clutching his bleeding arm — the wires now sparking erratically.
"Why… won't you die?" the scientist rasped.
"Because you don't deserve to die by my hand," Nagisa said, voice steady. "You deserve to remember. And I don't kill."
Erabus laughed weakly. "Remember…? I barely remember my own name."
Nagisa looked up sharply. "Then who are you?"
There was silence — a deep, aching pause that filled the ruined lab.
Then the scientist smiled faintly. "Not Erabus. Not anymore. My real name… was Hokuro Poku."
[FLASHBACK – The Birth of Erabus]
The world turned to sepia and static.The roar of the reactor faded into the gentle crackle of an old radio, the same kind that used to play in a small apartment in a distant city — before the world had forgotten him.
Hokuro sat beside his dying mother. The room was dim, lit by a single candle. The air smelled of medication and wilted flowers.Her voice was soft, brittle.
"You don't have to fix everything, my child… sometimes, you just have to feel it."
He was young then — barely twenty — his uniform still neat from the military academy. His hands were trembling as he held hers.
"Mom… I'll save you," he whispered.
She smiled, eyes half-closed. "You already have… by being here."
Then she was gone.
The radio kept playing.A song about the moon. He never even got to say goodbye.
He didn't cry that day. He didn't sleep either. He simply stared at the candle until it burned out, until the wax hardened like time itself.
The next morning, Hokuro enlisted again. He needed order — something to drown the silence. The military gave him that, for a while. Until he discovered science.It began with curiosity — repairing a broken communications module. Then it became obsession — modifying drones, designing artificial nerve links, learning how to rebuild what time had taken away.
He quit the military with honors, chasing the illusion of purpose.For years, he worked alone.He built prosthetics for veterans, organs for patients. People called him a hero. But every invention was just another step toward something deeper — her.
He wanted to bring his mother back.
He built the first resurrection machine from carbon-fiber skeletons and quantum interference engines. He called it the EVE-0 System.And he tested it… on her preserved DNA. His depression from her death fuelled him.
The explosion destroyed half his lab. The blast took his right eye and left leg. The world called it an accident. He called it all a failure.
Then came the dark years.Prison.Three times.Each time he was released, he tried again — each attempt worse than the last. He rebuilt his body, repaired his mind, replaced his heart with circuits that didn't feel.
Until he forgot why he began at all.
The flashback fractured again — jumping decades forward.He was older now, standing before government officials in a clean white lab.Behind him glowed a new experiment: a shimmering sphere of moonstone energy suspended in magnetic fields.
One of the officials asked, "What do you call it?"
He smiled weakly. "Project Erabus."
And thus began the end.
Back in the present, the light of the reactor pulsed red — collapsing.
Nagisa stood still, trembling as the vision faded from his mind. He'd seen grief before, but this was different. This was the story of a person who couldn't stop running from love — until it devoured him.
"Dr. Hokuro…" Nagisa whispered, stepping forward. "You don't have to do this anymore."
Erabus laughed hoarsely, tears running down his dirt-streaked face. "Don't… pity me, stude. I'm the reason your world bleeds."
"Then stop the bleeding," Nagisa said, almost shouting now. "You're still alive — that means there's still time."
Erabus's eyes softened — truly, for the first time. He looked almost human again.But then the core behind him began to surge uncontrollably.
Hakumura's voice cut through the comms again, panicked.
"Nagisa! Get out of there! The reactor's destabilizing — he's set it to collapse into a spatial vacuum!"
Nagisa turned to run, but Erabus caught his arm weakly. "Let me… end it. Please."
Nagisa hesitated, tears stinging his eyes. "Don't—"
"Every scientist deserves the chance to fix their final mistake," Erabus said quietly. "Let me have that."
Nagisa's grip loosened. Slowly, painfully, he stepped back.Erabus smiled faintly, turned to the reactor console, and began entering override commands with trembling fingers.
"Tell your students," he murmured, "that even monsters can remember the light… even if only for a second."
The reactor core blazed like a recoiled sun.The last thing Nagisa saw before the explosion was Erabus standing tall, backlit by his own creation — smiling the way a person somtimes does when they finally forgive themselves.
Then, everything turned white...
Episode 13: "The Mirror of Erabus — Part II" (Conclusion Of Arc)
The world was silence.
Not the kind of silence that came from peace — but the kind that followed destruction. The kind that hummed beneath your heartbeat, whispering, "You survived, but not unbroken."
Nagisa's eyes fluttered open to a sea of gray ash. The world around him was unrecognizable.Where the Erabus facility once stood — its shimmering towers, its mechanical heart — there was only ruin.The air shimmered faintly, laced with particles of moonstone dust. They hung in the sky like dying stars.
He coughed, tasting metal and blood. "...Hakumura?"No answer.Only the faint hiss of burning debris.
He pushed himself up, every muscle screaming. The impact had thrown him halfway across the complex — his uniform torn, hair matted with soot. His dull knife lay beside him, scorched but intact.
He reached for it slowly, gripping it as though holding a memory.
He's gone, Nagisa thought.Dr. Erabus. Hokuro Poku. The scientist who wanted to fix everything, and broke everything instead.
He could still feel the echo of that final smile burned into his mind — not the smirk of a mad scientist, but the trembling gratitude of a human who finally understood the word forgiveness.
The wind carried ash across his face, cold and heavy. Somewhere in that dust, he could almost hear Koro-sensei's voice:
"Even when you've saved the world, Nagisa… make sure you don't lose yourself in it."
He let out a shuddering breath. "I'm trying, Sensei… I really am."
The Wreckage
Nagisa stumbled through the remains, searching for signs of life. The facility had collapsed inward — a crater of twisted steel and molten glass. In the distance, fire still licked at the sky.
A broken console sparked weakly. On instinct, he knelt beside it.The screen flickered, then glitched to life — showing faint traces of system logs.
ERABUS PROTOCOL: TERMINATED.
DATA TRANSFER: 12%...FAILURE.
Nagisa frowned. Transfer?Then his heart sank.If part of the system had escaped the destruction… then Erabus might not have died alone.
Before he could think further, a voice called out — hoarse but alive.
"Nagisa—!"
He turned sharply. Through the dust, a figure stumbled forward, clutching a damaged arm."Hakumura!"
The young person looked half-dead, burns tracing his cheek, but his eyes were clear — clear and trembling.Nagisa ran to him, catching him before he collapsed.
"I thought—" Hakumura gasped, "I thought the blast got you…"
Nagisa smiled faintly. "Guess I'm harder to erase than I look."
Hakumura let out a laugh — broken, half-delirious, but real. "He's gone, right? That lunatic's gone?"
Nagisa hesitated. He looked back toward the crater, where faint blue light still pulsed beneath the rubble."He is. But what he created… might not be."
Hakumura followed his gaze, expression darkening. "You mean the data—?"
Nagisa nodded slowly. "He was trying to transfer it before the explosion. I think he only got part of it through. If that's true, someone — somewhere — might still be running his program."
Hakumura's hand clenched. "Then all this… was for nothing?"
Nagisa's voice was quiet. "No. For the first time… I think it was for something."
They sat in silence for a long while. The fires hissed around them, embers glowing like stars against the broken steel.
Nagisa closed his eyes, listening to the faint hum of the wind. He could almost hear children's laughter — old echoes from a school that no longer stood. Class 3-E. The hill. The sunset. Koro-sensei's strange, warm smile.
Every lesson, every tear, every goodbye.
"Assassination is not the act of ending life," Koro-sensei had once told them. "It's the art of understanding its worth."
Nagisa whispered the words now, voice breaking. "Then I understand, Sensei. Even monsters… have worth."
Hakumura looked at him, quiet for a moment. "You really believe that? After what that freak did?"
Nagisa turned, meeting his gaze. His expression was weary, but unwavering."Yes. Because if I stop believing that… I become one myself."
The Ghost Memory
Night fell over the ruins.The two survivors made camp beneath the fractured dome of the once-great facility. The stars shimmered faintly through gaps in the steel.Nagisa sat alone under the moonlight, his dull knife in hand, staring at its reflection.
For a moment, he thought he saw Koro-sensei's smile reflected there. Then it shifted — into another face. Hokuro's.
He blinked. The image didn't vanish.
He frowned. "...Hakumura."
The other person looked up from where he was patching his arm. "Yeah?"
"Do you… see that?"
Hakumura turned — but there was nothing in the knife's reflection for him."See what?"
Nagisa hesitated. "Never mind."
But as he looked again, the reflection changed — now showing a younger Hokuro, eyes wide and full of determination. The person before the madness.
And in that moment, Nagisa heard his voice.
"Do you know what it's like," the reflection whispered, "to live your whole life trying to fix something you never broke?"
Nagisa's throat tightened. "I think… I do."
The reflection tilted its head, smiling faintly. "Then maybe we're not so different, you and I. You seek peace through forgiveness. I sought peace through control. We both wanted to heal the same wound."
Nagisa's hands trembled. "You caused so much pain."
"I know," said the reflection softly. "But you forget — pain was the only language I remembered."
Then the reflection flickered out, leaving only the cold steel of the blade. An imagination that Nagisa had come imagined through sorrow alone himself.
Nagisa lowered it slowly, eyes wet.For the first time, he didn't see an enemy when he thought of Erabus.He saw a broken being, chasing the ghost of his mother through science and sin — and failing because he couldn't forgive himself for surviving her.
"Maybe that's what it means," Nagisa murmured to himself, "to lose the lesson."
Hakumura frowned. "Lesson?"
Nagisa smiled faintly. "He never learned what Koro-sensei tried to teach all of us. That purpose without heart… is just machinery."
The Heart That Still Beats
By morning, rescue drones from the outer defense network had arrived — anonymous, unmarked, government-issued. They combed through the debris, collecting data, scanning for survivors.
Nagisa watched from afar. He knew better than to approach. These weren't rescue teams — they were erasers. Sent to clean up the remnants of Project Erabus, erase every trace of the truth.
Hakumura joined him, wrapping a fresh bandage around his arm. "You think they'll find anything?"
"They'll find what they want to find," Nagisa replied quietly. "Nothing more."
The wind blew through the ruins, scattering papers, fragments of moonstone dust glittering in the dawn light.For a brief moment, the world looked peaceful — beautiful, even. Like it had been washed clean.
Nagisa stared at it all, his reflection mirrored in the broken glass around him. His eyes looked older — not tired, but wiser.
He spoke softly, mostly to himself.
"You know, Sensei… I used to think justice was about punishment. About stopping bad people from hurting others. But maybe… justice is really just empathy in disguise."
Hakumura looked at him, brow furrowed. "You always talk like that when the world's burning around you."
Nagisa chuckled faintly. "Maybe that's when it matters most."
Hakumura smirked, shaking his head. "You're impossible, Shiota."
"Maybe," Nagisa said, smiling softly, "but we're still here."
The Final Memory — Dr. Erabus
As they prepared to leave, Nagisa spotted something half-buried in the rubble — a small, cracked memory chip. He knelt, brushing away the dust.Stamped on its side was a single word: "HOKURO."
He inserted it into his portable console laptop. The screen flickered, showing a final message.It was a recording — a video log.
The face of Dr. Hokuro appeared, older, weary, and almost… human again. He spoke slowly, voice trembling.
"If anyone finds this… it means I've failed.
I thought I could fix the world through control — that science could cure what love could not. I was wrong. I became the thing I feared most: a god who forgot what it meant to be human.
If the one watching this is Nagisa Shiota… then you already know the truth. Koro-sensei wasn't the monster we made him out to be. He was the dream I couldn't reach.
I used to think I was cursed to lose everything I loved. My mother, my friends, my own sanity. But maybe the curse was never losing them — it was refusing to remember them.
So… thank you. For reminding me."
He paused, smiling faintly — the same broken smile Nagisa had seen before the explosion.
"Tell your students, Shiota… don't let their purpose turn to ash like mine did. And if you ever find my mother's photo — tell her I'm coming home. I can tell if your seeing this you've won Shiota."
The screen faded to black.
Nagisa sat still for a long time, tears silently falling onto the cracked earth.Then he whispered, voice trembling but clear:
"Rest well, Dr. Hokuro. You made it home."
Epilogue – The Shattered Moon
Weeks passed.
Japan's skies were quiet again, though the moon hung heavy — scarred and fractured, but still shining.Nagisa stood on the rooftop of his repaired apartment, the wind brushing through his hair.
The world had moved on quickly. The government had buried Project Erabus under layers of classified silence. But Nagisa hadn't forgotten. He never would.
Beside him, Hakumura leaned against the railing, sipping from a can of coffee. "So… what now, sensei?"
Nagisa smiled faintly at the word. "Now? We rebuild. There's always another lesson."
Hakumura looked at him. "Even after all that?"
"Especially after all that," Nagisa replied. "Because people like Hokuro taught me something I didn't expect — even those who fall the furthest… leave behind a reason to climb."
The younger one sighed. "You're still too good for this world, you know that?"
Nagisa laughed quietly. "Maybe. But that's why Koro-sensei trusted me with it."
He gazed up at the moon — broken, glowing softly through the clouds.For a moment, he could almost see it whole again.
And in that silver light, he heard them — faint voices from a classroom on a hill:
"Shiota-kun, you're always thinking too much!"
"C'mon, teach! Time for the next lesson!"
"Nagisa… smile for us."
He smiled — truly smiled — for the first time since the war began.
"Alright, Sensei," he whispered. "Lesson learned."
[CREDITS SCENE – The Hidden Transmission]
Static.A dark room.A terminal still glowing beneath the ruins of the Erabus facility.
DATA TRANSFER COMPLETE.
RECEIVER: UNKNOWN.
PROJECT ERABUS – PHASE II ACTIVATED.
A faint, childlike voice spoke through the static:
"Hello, Father. I've been waiting."
The screen flickered — then went black.
To Be Continued...