Itona straightened inside the white cage, tentacles already unfurling. Anti-sensei blades gleamed along their lengths.
"Koro-sensei… compared to me, you are… weak…"
All four tentacles shot forward at once.
Koro-sensei twisted and dodged as best he could, but the enclosed space of anti-sensei sheets left him almost no room to maneuver. One blade scraped across his side. Another clipped a tentacle. He took more damage in those first few seconds than he had in most of their previous encounters.
Outside the cage, Shiro watched with calm satisfaction.
"First we make drastic changes to the field. Then we attack. Easier to confine him first, then strike." He glanced toward the students. "I've taken a page from your tactics, you see."
Akira's voice was flat.
"So this is the plan you came up with."
"Exactly. Once that creature starts losing his students' trust, his movements grow panicked. Even if things seem a little off, he'll dive right in—the fool. What Itona has on his tentacles are gloves with sharp edges made of anti-sensei material—"
"No," Akira interrupted. "What I meant was… you were gone for a long time, and this is all you could come up with? Don't you have any creativity?"
Shiro's masked face turned toward him. The air around him seemed to drop several degrees.
Akira continued without concern.
"I mean, the process of luring him wasn't bad. The anti-sensei sheet cage isn't bad either. But the method of finishing him off… lacks originality."
Shiro frowned.
"What did you say?"
Akira ignored the threat entirely and raised his phone.
"Alright, everyone. I have a drone above us. We can see inside the sheets."
The students quickly gathered around the screen. The live feed showed Koro-sensei and Itona clashing inside the white cage.
Shiro's gloved hands clenched into fists.
"As long as he dies today, my plan works."
Akira waved a hand dismissively, eyes still on the phone.
"Yeah, yeah. Whatever."
Shiro looked like he wanted nothing more than to punch him, but remembering Akira's strength, he decided it wasn't worth it.
On the screen, Itona's tentacles continued their relentless assault. Every surface around Koro-sensei was deadly to the touch, forcing him into narrower and narrower escapes.
Koro-sensei suddenly shot upward, trying to leave the cage from above.
Itona's tentacle snapped out and caught him.
"I won, big brother." Itona's voice was cold. "By killing you, I'm solving just one problem."
He slammed Koro-sensei back down into the cage hard enough to crack the ground.
"I am proving… my strength!"
All four bladed tentacles converged on Koro-sensei at once.
This time, Koro-sensei slipped between them as if the attacks were moving in slow motion.
Itona's eyes widened. He attacked again, faster, from every angle.
Every strike missed.
Koro-sensei weaved through the storm of blades, his voice calm even while dodging.
"Yes, very well done, Itona-kun! If this were before the first term, you may very well have killed me. But your attack pattern is a simple one. No matter how fast you are, no matter how strong… no matter how many schemes your guardian thinks up… no matter how easily I freak out… by our third fight, I can see and adapt to your patterns."
Outside the cage, Akira threw both hands up as if he had just been proven right in a long argument.
"See?! I told you so! No originality!"
Itona landed on the top edge of the sheet walls, breathing hard.
"No way… it can't be…"
He launched every tentacle downward in one final, desperate wave.
Koro-sensei caught all four of them at once with his own tentacles and the fabric of his robes, holding them motionless.
"Itona-kun… I study, too, you know." His voice was quiet but firm. "How could I teach anyone if I didn't grow and learn day by day?"
Akira glanced at his phone.
"Heard that, Ritsu? That's why I told you your initial calculations were wrong. They didn't account for him growing too."
"I was still in my previous version, okay?" Ritsu muttered.
Erika's voice cut through the commentary, sharp and annoyed.
"Guys. There is a serious fight going on here."
Inside the destroyed remains of the cage, Koro-sensei sighed and released Itona's tentacles.
"Now… let's get rid of this dangerous cloth cage."
He drew several of his own tentacles together into a single point. Light began to gather there, growing brighter and denser with every second.
"Experiencing my Absolute Defense form, and my experiments with Akira-kun over the vacation, taught me yet another skill."
The glow intensified.
"Compressing not my whole body, but a portion of my tentacles… to release a burst of energy."
Outside, Shiro took an involuntary step back as the light pulsed against the white sheets.
"Wh-what…?"
Koro-sensei's voice rose over the growing hum.
"Remember this, Itona-kun. I say assassination is education. The Assassination Classroom's teacher will get stronger every time he teaches!"
WHOOOOOOOM!
A brilliant white beam erupted upward.
The anti-sensei sheets disintegrated on contact. The shockwave blasted Itona clean off and sent the remains of the cage flying in every direction.
Akira watched the fading light and nodded in mild approval.
"…Great. He can Kamehameha now."
Koro-sensei caught Itona before he could hit the ground and turned toward Shiro, still holding the boy carefully.
"So there you have it, Shiro-san. Leave him to Class E and go quietly. Oh, and… spread the accurate word that I am not an underwear thief!"
Kayano pumped a fist.
"And I'm actually a B-cup! A B-cup!"
Akira glanced at her with clinical honesty.
"Really? Your measurements are a bit smaller, though. I'd say A."
Kayano stumbled backward, both hands flying to her chest.
"How did you know my cup size?!"
Before Akira could answer, Erika's hand clamped down on his shoulder.
"Let's have a talk."
"Wait, I'm innocent!" Akira said quickly. "I can just see her size by looking at her chest—"
Erika's eyes narrowed.
"Then why are you looking at her chest?"
Silence.
Absolute silence.
Akira's face went pale.
"I am innocent, believe me—!"
Erika already had him in a rear naked choke.
While the two of them struggled off to the side, Koro-sensei and Shiro faced each other in a brief, heavy silence.
Then Itona suddenly screamed.
"Ahhhhhh!"
He fell from Koro-sensei's tentacles and collapsed to the ground, writhing. The tentacles along his head began to swell unnaturally.
"Itona!"
"My head's… killing me!" Itona clutched at his skull. "My brain's about to burst!"
Shiro watched without emotion.
"With the shock of his repeated defeats, his tentacles are starting to gnaw away at his mind."
Koro-sensei's voice sharpened.
"Hang in there, Itona!"
Shiro continued as if discussing a failed experiment.
"This might be all he can take. Why, he can't even pull off this little scheme of mine." He looked down at the boy. "Itona. If this is all you're capable of, the organization will stop paying. It's not that I don't feel sorry for you, but we have to cut our losses at some point… if only to get the next model up and running."
He turned away.
"This is goodbye, Itona. You're on your own now. You have two to three days before you die, now that I've stopped your treatments. Take care."
Koro-sensei moved forward.
"Wait! What do you mean he will die soon?! What kind of guardian are you?!"
Shiro glanced back over his shoulder, his voice cold.
"Quit playing school, you monster. All you can do is break things… break everything. I will not countenance your existence. I wish only for your death… no matter the sacrifice."
He vaulted over the wall and disappeared.
Just before he vanished completely, his voice drifted back.
"Say… are you sure your dear students are okay like that?"
Itona's tentacles turned jet black.
With a feral cry, he lunged straight toward the group of students.
Koro-sensei tried to intercept, but the energy beam had left him noticeably slower. He wouldn't make it in time.
A figure stepped in front of the charging boy.
Akira—released from the choke for emergency pending investigation—caught Itona's blackened tentacles mid-strike.
"Sorry, Itona. I calculated your movements long ago."
He twisted, slammed the boy face-down into the ground, and kept a firm hand on the back of his head.
"Now keep quiet while we finish this."
Koro-sensei looked mildly distressed.
"Akira-kun, you should have been gentler."
Akira didn't ease the pressure.
"But Koro-sensei, emergency violence is justified."
The entire class shouted at once.
"No it isn't!"
Nagisa quickly stepped closer, his expression serious.
"Wait—before that. He said Itona will die in three days, right? What should we do?"
Karma crossed his arms.
"Can we remove his tentacles?"
Koro-sensei shook his head.
"As long as Itona has a pathological attachment to power and winning, his tentacle cells will stick so tightly that we can't remove them."
Terasaka frowned.
"We can't cut them off somehow?"
"Not until we get rid of that attachment," Koro-sensei answered. "That's why we have to know more about how he got this way."
Akira kept Itona pinned, but his voice remained calm.
"Koro-sensei. I might have a way to help him."
Koro-sensei turned to him in surprise.
"…You do?"
Akira kept one hand firmly on the back of Itona's head and looked up at the others.
"Yeah. I made something that can possibly help us in this situation… though I never tested it before."
Koro-sensei's eyes narrowed slightly.
"Why didn't you test it before?"
"Koro-sensei, people with tentacles aren't exactly running around everywhere," Akira replied. "There are only two of you I know, and I couldn't exactly test it on you, right?"
"…That does make sense."
Fuwa leaned forward.
"Wait. You made a… a what?"
Karma tilted his head.
"Some kind of tentacle cure?"
"No." Akira shook his head. "I didn't make a cure. This is something different."
Koro-sensei floated a little closer.
"Come on, Akira-kun. Don't keep us waiting. Tell us what it is."
Still pinning Itona, Akira reached into his back pocket with his free hand and pulled out a sleek, futuristic syringe gun. Inside the chamber, a glowing yellow liquid pulsed softly.
"This is a tentacle-connection serum. I made it using the tentacle cells I recovered from you, Koro-sensei. It should give the user an extremely strong affinity with the tentacles. Strong enough that, theoretically, if the user's connection is stronger than the current host's, the tentacles should detach and transfer to the new host."
He looked down at Itona.
"So I'm going to take his tentacles."
The entire group exploded at once.
"Absolutely not!"
"Akira-kun, it's dangerous!" Koro-sensei said.
Erika's voice was sharper.
"Do you want me to lock you up? Is that it?"
Nagisa stepped forward, worried.
"Akira-kun, if you do that… won't you be the one who dies in three days?"
Akira remained calm.
"Everyone, calm down. I have a plan. Just trust me."
Erika's eyes narrowed further.
"No. I already told you not to do dangerous experiments with your own body. And Koro-sensei can remove them himself once we know more about—"
"I know," Akira interrupted quietly. "But I just want to try something. Don't worry. It'll be over soon."
Before anyone could grab him, he pressed the syringe gun against the back of his own hand—the same hand holding Itona down—and injected the glowing serum.
"Wait—!"
For a second, nothing happened.
Then thin, glowing white lines spread from the injection point across Akira's hand and wrist. Itona's blackened tentacles shuddered, then began crawling toward the light, turning white. One by one, they detached from Itona's head and latched onto Akira instead.
Itona's body went limp.
The white lines continued climbing up Akira's arm, reaching his shoulder, his neck, and finally the side of his head. His eyes flashed a bright, glowing white.
For a moment, the transferred tentacles writhed as if in agony.
Then, with a violent full-body flinch, they tore themselves free from Akira, dropped to the ground, and melted into nothing.
Silence.
Everyone stared.
Akira blinked. The white glow faded from his eyes, leaving him looking completely normal.
"See? I told you it wasn't that much."
Erika was already at his side, gripping his wrist.
"Are you alright?"
Koro-sensei floated closer, clearly unsettled.
"What happened?"
Nagisa looked at the dissolving remains on the ground.
"Did the tentacles… self-destruct?"
Akira rolled his shoulder, testing it.
"Well… the tentacles asked me what I wanted to become. I told them, 'Who the hell do you think you are? I'm already the perfect creature. Get the hell out of me.' And they just… self-destructed."
The explanation was so absurd that no one spoke for several seconds.
Koro-sensei finally managed a weak,
"…Eh? What?"
Akira gestured to himself as if the answer should have been obvious.
"I mean, look at me. I am the most handsome, intelligent, talented, cool guy in the world."
Erika didn't even hesitate.
"You forgot to add 'humble' to that list."
"That's because I'm too humble to add it," Akira replied seriously. "Anyway, there's basically no one better than me, so I don't need tentacles coming out of my head to make me better. It would only reduce my handsomeness."
The class exchanged glances. No one was sure whether the logic made sense or not. They all looked to Koro-sensei for guidance, but the one who seemed the most lost was him.
Erika exhaled and tightened her grip on Akira's wrist.
"Anyway. Since you put yourself through another dangerous experiment… I will have to punish you."
Akira's eyes widened.
"Wait—it wasn't dangerous! I promise it wasn't dangerous!"
While Akira and Erika were still discussing his punishment in what could only generously be called a peaceful manner, Karma pointed at the unconscious boy on the ground.
"So… what should we do with him?"
Everyone turned to look at Itona.
Koro-sensei's expression softened.
"He is my student too. And part of Class 3-E. We will take him in."
Fuwa frowned slightly.
"But we don't know anything about him."
"Let's talk to Karasuma-sensei first," Koro-sensei replied.
Akira reached into his pocket and held out a thin data drive.
"Well, about that."
He placed it in Koro-sensei's tentacles.
"That's everything I have on him. His backstory, family details, medical information, and a few other things. You should take care of him from here."
Nagisa blinked.
"…Is that legal?"
Karma shrugged.
"Too late to talk about it now."
Koro-sensei accepted the drive with both tentacles. For once, his usual playful tone was completely gone.
"…Thank you, Akira-kun."
Akira waved a hand and turned away.
"Don't worry about it. Now I have anime to watch. I'll be on my way."
Erika's hand shot out and caught his shoulder before he could take a second step.
"Where do you think you're going? Today you did a lot of naughty things. You know unusual information about F-cup girls, and you performed another dangerous experiment on yourself. Don't you want to explain all of that to me?"
Akira's voice turned careful.
"Erika, let's talk peacefully. No need for violence."
She began dragging him toward the street without another word.
"Sure. Let's go home and talk about what to do with you."
"Come on, everyone!" Akira called over his shoulder, digging his heels in. "Don't just stand there—save me!"
No one moved.
The rest of the class had already gathered around the unconscious Itona, talking quietly among themselves.
Akira's final cry of "You traitors!" faded into the night as Erika pulled him away.
---
On the way home, with nothing left to do, Akira reached out telepathically.
"Hey, sis. Did you see that?"
Selena's voice came back, calm and slightly pointed.
"No. You told me not to read your mind, remember? Anyway… what did you see?"
Akira was quiet for a moment, eyes on the dark street ahead.
"…Something weird. When the tentacles connected, it wasn't just will. There was something else underneath. I don't know what it was."
Selena asked,
"Can you identify it?"
"Not yet." He glanced up at the night sky. "I need more data."
Selena's tone softened just a little.
"Well done for now. Good luck with your punishment."
Akira cried.
"Please save me."
The connection cut off without another word.
That night, Akira received a grim reminder.
Never upset Erika.