Back at the house, Akira sat at the table with a notebook open, drawing like the page had personally challenged him.
Erika came down after changing out of her uniform and leaned over his shoulder.
The sketch was armor.
Fitted plates. A narrower waist. Lines that did not look like his.
"What is this?" she asked. "New armor for you? But why does this one look more feminine?"
Akira did not stop the pencil.
"Because this one is not for me. It's for you."
Erika pulled back a little.
"What are you up to now?"
"Well, I originally wanted to make myself stronger so I could protect you. Then I realized I can't always stay near you." He pointed at the sketch. "So if I can't always protect you myself, the next best thing is making you stronger."
Erika understood exactly what he meant.
She sighed.
"Akira. I'm perfectly capable of getting stronger myself."
Akira smiled.
"I know. But there is nothing wrong with growing even stronger, right?"
Erika sighed, trying to divert his attention.
"Don't you have some other important thing to do?"
That landed.
Akira's pencil stopped.
"Yeah. I think Ritsu's E-skin is completely synthesized by now. All that's left is to install it into her body, calibrate it, and connect it to her artificial sensory network."
Erika's shoulders loosened.
"Yeah. Go do that instead of this."
Akira nodded.
"Fine. I'll finish that first."
He left the notebook on the table and went downstairs.
Erika stayed where she was for one peaceful second, relieved he had left the armor alone.
Then the rest of the sentence caught up with her.
Synthetic skin.
Once it was on, Ritsu would look like an actual human girl.
And Akira would be standing there working on a naked girl.
Erika ran after him.
"Stop right there. I will not approve it!"
Akira had just opened the synthesizer. He looked back.
"What happened?"
Erika saw it.
The E-skin in the tray looked far too much like a human girl's skin.
"This is so creepy. Close your eyes."
She covered them with her hand, yanked him away from the machine, and shut the synthesizer herself.
Only then did she let go.
Akira blinked at her.
"Wh-what was that about?"
She immediately scolded him.
"Akira. Bad. You shouldn't see girls naked."
Akira looked even more confused.
"But I am making her. And it's not real skin."
Erika snapped.
"That's not the point."
She turned to the screen above her robot body.
"Ritsu. You don't want anyone to see you, right?"
Ritsu tilted her head on the monitor.
"I don't mind if it's Akira-kun. I mean, he made it."
Akira pointed at the screen, helpful.
"Yeah. She won't mind."
Erika looked at both of them with an expression that said she could not believe she was having this conversation.
"What? No. I will not allow it. Think of something else. Something normal. Can't you make those robot arms do it?"
Akira shook his head.
"I don't know. This process is sensitive. I don't want to damage her skin. She needs human touch."
The words were already out before he heard them.
Erika's red face said she had heard them just fine.
"You cannot touch her. I will touch her. And you cannot look either. Do it with a blindfold."
Akira frowned.
"And how exactly am I supposed to do that? Besides, you don't know anything about this."
Erika thought for a bit and then said,
"You can guide me. As for your eyes, close them and use your Transparent World. You can do that, right?"
Ritsu's voice came from the speaker.
"Transparent World?"
"Don't worry about it," Erika said.
Akira thought it over.
"It's not that simple. I can't maintain Transparent World for a long time, and I'm not sure how the precise, delicate work will go like that…" He paused. "…But it does sound like a nice challenge."
"Yeah," Erika said. "Let's do that."
Erika already had her handkerchief. She tied it over his eyes before he could argue.
"Alright. Can you see?"
"Couldn't you give me some time?" Akira sighed, then activated Transparent World. "Whatever. First, take her skin out and place it on her body. I'll guide you on what to do next."
Erika did.
The synthesizer opened. The skin went onto the metal frame.
"What's next?"
She did not get an answer in words.
Akira stepped in behind her, put his arms around her, and closed his hands over hers.
Erika jumped.
"Wh-wh-what are you doing?"
"Well," Akira said, blind and perfectly reasonable, "if I can't touch her, I can touch you, right? You can touch her. So I can use your hands to work on her."
Erika's whole face burned.
"But that's—"
Ritsu sounded genuinely curious.
"Is it some kind of romance?"
"Noooo!" they both shouted.
After that, nothing about the work was simple.
Akira could only hold Transparent World in short bursts. Erika had to wait each time the world went dull for him. He steered her fingers. She did the touching. Ritsu offered occasional comments that did not help.
They finished anyway.
The moment the last connection set, Erika shoved him toward the stairs.
"Out. I need to dress her."
The basement door shut in his face.
Akira stood in the hallway, still blindfolded, locked out again, muttering, "But that's my lab."
---
The next day, class started like normal.
Nagisa looked down at his desk. He had been talking about his mother coming to meet the teacher and some of the troubles he was facing.
Sugino winced.
"Your mom, huh? She's a tough cookie."
Nagisa sighed.
"Koro-sensei said to let him handle it, but…"
Nakamura cut across him, staring at the silent box in the corner.
"Wait. Why isn't Ritsu turning on?"
Maehara checked his phone.
"Hey. She would usually be on by now. Even the mobile Ritsu app isn't working."
The class started to murmur.
Then the door opened.
Koro-sensei and Irina came in with the same stunned looks still stuck on their faces.
Akira and Erika followed them.
Both of them were smiling like they knew something the room did not.
Koro-sensei clapped his tentacles together, a little too brightly.
"Good morning, everyone! Well, today we have a new student joining our class!"
The room erupted at once.
"Seriously? A new student this late?"
"Who could it be?"
"Is it an assassin again?"
"Of course it's an assassin. I just hope it's a normal one."
Okajima leaned forward.
"I wonder if it's a cute girl."
Koro-sensei lifted a tentacle toward the door.
"Now then. Let's welcome Ritsu-san."
A girl walked in.
Lilac hair. Blue eyes. A school uniform that sat on her like it had always belonged there.
She stopped at the front of the room and smiled.
"Good morning, everyone."
The class exploded.
"Whaaaaaaatttttt?!"
"Wait. Is that Ritsu?"
"Wait. Ritsu is human now?"
"How did that happen?!"
Ritsu's smile did not change.
"This is a new body made by Akira-kun."
Every head turned.
Akira raised a hand, modest and not modest at all.
"Oh, don't be like that. It was a team effort."
The class answered together.
"Of course it's you."
Nobody noticed Erika look away, her ears a little red.
Koro-sensei cleared his throat.
"Now, Ritsu-san. Please go sit in your seat."
Ritsu glanced at the corner.
"But, Koro-sensei, I don't have a bench."
Koro-sensei pointed toward the back.
"Yes. Your old body is occupying it. We can place a chair next to it."
They did.
Ritsu sat beside the silent artillery box like it was the most normal thing in Class E.
The moment she sat down, the class closed in.
"Are you a cyborg?"
"Is that skin real?"
"How did you guys even do this?"
Nakamura took her hand before anyone could stop her.
"…It feels just like a human's."
Ritsu looked down at their joined hands, curious and pleased.
"Yes. This is synthetic E-skin. It feels just like human skin. And I can feel with it, just like a human too."
The noise jumped again.
"She can feel?"
"What kind of technology is this?"
Koro-sensei wiped at his eyes.
"My students are all getting along…"
Irina stared at him.
"That's what you're worried about?"
Ritsu raised her other hand.
"Koro-sensei. I have a request."
Koro-sensei wiped his tears.
"What is it, Ritsu-san?"
"You see, I have this new body and all. I want to test it, so…" She smiled a little wider. "Can I assassinate you this afternoon?"
Koro-sensei brightened at once.
"Of course, Ritsu-san. I'd be happy to see how much you've grown. Just remember—an assassination attempt is also an opportunity to learn."
Ritsu nodded.
"Understood, Koro-sensei."
The class had the same thought at the same time.
She's booking assassinations now?
---
The rest of the day went normally.
Well, aside from Nagisa's mom causing a commotion that even scared Akira into latching onto Erika's sleeve until the hallway cleared.
Then the final bell rang.
Koro-sensei shut his book.
"Well, that's all for now. Don't forget to finish the homework." His eyes found the new girl by the silent box. "Ritsu-san. Are you ready?"
Ritsu stood.
"Yes, Koro-sensei. I am ready."
Nagisa looked at her empty hands.
"Ritsu. Do you have any weapon?"
Ritsu smiled.
"Don't worry. I have my weapon."
She walked over to her old body and held out her hand.
A handle unfolded from the artillery box with a clean metallic click.
She lifted the whole thing as if it had always been meant to be carried.
Under everyone's shocked gaze, she tilted her head.
"Are you ready, Koro-sensei?"
They took it outside.
The mountain yard behind the building. Class E and Irina lined the edge to watch.
Ritsu held the huge black coffin like a minigun.
"Then, here I go."
The monolith opened.
Two Gatling guns slid out and screamed.
Koro-sensei slipped between the streams, laughing.
"Nuruhuhuhu! An attack like this is not enough to hurt me, Ritsu-san!"
"I know."
She closed the distance at a speed no ordinary student could match.
The box opened again. Two shotguns kicked. Koro-sensei bent around both bursts like they were polite suggestions.
Then Ritsu jumped.
Boosters kicked in from the back of the coffin and threw her higher.
Anti-sensei BBs rained down from above.
Nagisa did not take his eyes off the sky.
"Akira-kun. Did you upgrade her old body like this?"
Akira had his hands in his pockets.
"Yeah."
Nakamura stared at the flying coffin.
"But why use her old body as a weapon?"
"That's Ritsu's idea. She got it after watching some anime with me." Akira sounded faintly proud. "She said she is a bit attached to her old body."
The class turned on him as one.
So it was you who corrupted her.
Akira kept going anyway.
"I call it the Compact Artillery Box. CA Box for short."
A long, tired pause.
Seriously? CA Box?
In the yard, the aerial barrage did not tag Koro-sensei.
It did throw a lot of dirt into the air.
Koro-sensei peeked through it.
"Is that it, Ritsu-san?"
Ritsu landed, still smiling.
"Just as planned."
The CA Box coughed out grenades.
They missed him on purpose.
Smoke poured across the ground, thick and wrong-colored. Visibility dropped. Koro-sensei started to melt.
"Anti-sensei smoke?"
"Not just that."
Missiles left the coffin next.
Koro-sensei dodged the warheads.
They hit the dirt around his feet instead.
Anti-sensei paste splashed up and grabbed his lower tentacles for a second too long.
"Now."
The CA Box opened down the center.
The main cannon lit red.
A short charge.
Then a beam.
It crossed the yard like it had never needed time.
The class froze.
Akira's voice was almost lazy.
"That's an anti-sensei laser cannon. Yes. It was actually fired at the speed of light."
Someone whispered it first.
"Speed of light?"
"That's faster than Koro-sensei."
"Does that mean she got him?"
The smoke tore apart.
Koro-sensei stumbled out of it, breathing hard.
Part of him was missing.
The class did not make a sound.
Ritsu saw he was still standing and lowered the coffin at once.
"Energy output reduced. Switching to normal mode."
Koro-sensei patted his tie with a remaining tentacle.
"My clothes are okay. Only my tentacles?"
Akira nodded.
"Yeah. It only hurts tentacle-based creatures." He squinted. "But how did you dodge a light-speed attack?"
The missing pieces were already crawling back.
Koro-sensei puffed up, recovering his voice.
"That's because Sensei pushed my speed limit and surpassed my previous speed."
Akira did not even blink.
"No. You just have super intuition."
Koro-sensei let the joke die on its own.
"Anyway. Ritsu-san, you almost got me. That's good."
Ritsu bowed a little, the coffin resting against her leg like a school bag that could end the world.
"Thank you, Koro-sensei. Now I can help my classmates more."
That was the signal.
The class closed in, already talking over each other about Gatling guns and paste and a laser that should not have existed on a mountain campus.
Erika leaned toward Akira without looking away from the circle.
"She had more tricks up her sleeve, right? Why didn't she use them?"
Akira watched Ritsu smile in the middle of all that noise.
"Who knows. She has her own thoughts."
He smiled too.