In June, as the rain kept falling and the damp, sticky rainy season began, a change came to our classroom.

“Alright everyone, you’ve already heard from Karasuma-sensei that a transfer student is coming, right?”

“Yeah, honestly, they’re probably an assassin.”

“Tch, another transfer student assassin, that makes Ayanokōji, a transfer student too, look like he’s got no place here, hahaha.”

Terasaka said that while looking at me.

But in this classroom, a guy like me who transfers in normally is probably the rare one.

“Nuruhuhu, we underestimated things with Ritsu-san and got burned, so Sensei won’t let his guard down this time!! Either way, it’s a good thing when everyone gains another ally.”

“Speaking of which, Ritsu, as a fellow transfer student assassin, haven’t you heard anything?”

“Yes, just a little. Under the initial order, the plan was to deploy me and him at the same time. I would handle long-range shooting and he would handle close-range attacks, working together to corner Sensei, but that order was canceled for two reasons. One was that his adjustments took longer than planned. The other was that with my performance, I was not capable enough to support him, I was overwhelmingly inferior to him as an assassin…”

Ritsu is the one who blew off Korosensei’s finger and she’s being talked about like that, so what kind of monster is coming next?

While I was thinking that, the classroom door opened.

A man dressed entirely in white in a strange outfit was standing there.

“Sorry, sorry, I startled you. But the transfer student isn’t me. I’m their guardian. Well, I’m dressed like this, so just call me ‘Shiro’ or something.”

The man who called himself Shiro walked into the classroom with a friendly smile.

He’s hard to get a read on.

“Nice to meet you, Korosensei, the kid’s personality is a bit unusual, so I thought I’d introduce him directly in person, that’s why I came. Hey, ‘Itōna,’ come on in.”

Even after Shiro said that, there was still no sign of anyone coming in through the door at the front of the classroom.

More than that, I could faintly sense a presence approaching from behind.

No way…

““Dokan!””

With that impact, a boy busted through the wall as he entered the classroom and sat down next to Terasaka.

“I won! Therefore it has been proven that I am stronger than this classroom wall.”

““No! Come in through the door!””

Ignoring my classmates yelling back at him, I stared at the transfer student.

This guy isn’t just a normal human…

Maybe Karma sensed the same thing because he asked a question.

“Hey, Itōna-kun, something’s been bugging me. You just came in from outside empty-handed, right? It’s pouring rain outside, so why aren’t you wet by even a single drop?”

Ignoring Karma’s question, the boy called Itōna walked up toward Karma.

“You’re probably the strongest in this class. But don’t worry, you’re weaker than me, so I won’t kill you. The only ones I want to kill are the ones who might be stronger than me.”

With that, Itōna slowly approached Korosensei.

“In this classroom, it’s only you, Korosensei.”

“By strong and weak, do you mean fighting? Itōna-kun, in a contest of strength you can’t beat Sensei, you can’t even stand on the same level as me, hahaha.”

“I can. Because we’re ‘brothers’ who share blood…”

Saying that, the boy named Itōna raised his fist toward Korosensei.

“If you lose you die… big brother.”

“Nyu…”

“You don’t need tricks between brothers. I’ll kill you and prove my strength. After school, we fight in this classroom.”

After saying that, Itōna left somewhere together with Shiro.

If what he said earlier is true, I can also guess why he wasn’t wet from the rain.

This might become a good opportunity to push the class’s sense of unity to grow…

* * *

Karasuma POV

Right after the declaration of war, the student named Itōna went somewhere and the man calling himself Shiro was just laughing as he read a magazine.

Was that ‘brothers’ comment the truth, or was it just a tactic to shake him up?

What exactly is this man plotting?

“Hm? Ah, sorry for startling you, teachers. That kid is classified information of the highest level, so it’s only natural that even you, on the ground here, weren’t told. But I’ll guarantee it, that kid really is Korosensei’s brother and after school, that will be obvious to everyone.”

* * *

When morning classes ended and lunch break arrived, the classroom wasn’t fired up with the usual pointless chatter, it was consumed by the ‘brothers’ suspicion about Korosensei, brought on by what Itōna said earlier.

“That Itōna guy is eating sweets at an insane speed… being a sweet tooth is the same as Korosensei.”

“And how hard he is to read on his face too.”

“Nyu… everyone keeps comparing me and him because of this brother suspicion and I can feel more eyes on me than usual. It’s making me squirm. To freshen up, I’ll look at the gravure magazine I bought today. This is what you call an adult pastime!”

Korosensei struck a smug pose and started reading the gravure magazine, but almost at the same time, Itōna started reading the same magazine and the class erupted.

“This makes it way more believable!”

Okajima shouted, but there are actually scientific cases where siblings can have similar preferences in the opposite sex, so that’s probably what he meant.

“Is that true, Okajima-kun?”

“That’s right, Nagisa! Men who love big boobs are all brothers!!”

Looks like I was an idiot for even trying to take his side for a second.

“If they really are brothers, why doesn’t Korosensei know about Itōna-kun?”

“Hah, great question, Kayano-chi! Actually, Sensei and Itōna-kun are brothers who got separated long ago and Korosensei lost his memories from that time and when the two reunite, they don’t realize they’re brothers and they start a fated battle!”

“Okay, but why is only the little brother a human?”

“Well, like, a sudden mutation, or something? Hahaha.”

“You’re not digging into the important part at all, Fuwa-san. Work your plot more!”

“Eh, stories aren’t only about chasing realism!”

Their silly conversation lightened the heavy atmosphere from earlier and it felt like a bit of Class E’s usual liveliness was coming back.

But once after school comes, the classmates will feel it whether they want to or not…

The ‘threat’ of someone called Itōna…

And…

That everything we’d been doing as assassination until now was just playing around, that we’d only been soaking in lukewarm water all this time, that ‘softness’…

* * *

Even though the end-of-day chime rang, no one tried to go home like usual and everyone stayed quietly in the classroom.

Alright, even if you claim you’re Korosensei’s ‘brother,’ let’s see how far you can really go…

“You’re bored of ordinary assassination, aren’t you, Korosensei. So why don’t we set one rule? If you step even one foot outside the ring, you’re sentenced to death on the spot. How about it?”

“What the hell is that? Who's going to enforce it if you lose… a rule like that, right guys, you think so too?”

Sugino seemed to think Sensei didn’t need to follow the rules, but that’s wrong.

If he doesn’t follow a rule decided in front of everyone, his trust as a teacher drops.

The teacher version of himself ‘dying’ is something heavier than death for a guy who cares about his students more than anyone.

Nine times out of ten, he’ll accept this proposal.

“Fine! I accept that rule! But Itōna-kun, if you harm the spectators, you lose too.”

“Yeah, that’s fine.”

“Then we’ll start on the signal… Assassination… begin!”

““Doon!””

The instant Shiro gave the signal, Korosensei’s arm flew off.

But in that moment, the classmates’ eyes weren’t on Sensei, they were glued to Itōna.

“No way… ‘tentacles’?!”

“...Where did you get that… where did you obtain those ‘tentacles’…”

As he shouted and glared at Itōna, Sensei’s face was packed with a kind of anger I’d never seen before.

“You don’t have the right to ask, Korosensei, but now you get it, right? Different parents and different upbringing, but you two are undeniably brothers. Still… that’s a scary face. Did you remember something unpleasant?”

“Looks like, Shiro-san, I’ll have to question you too.”

“You can’t. Because you’re going to die.”

As he said that, Shiro aimed the light from a flashlight hidden in his sleeve at Sensei.

“Nyu?!… My body…”

“When this pressure beam is fired at close range, your cells react and your entire body stiffens for an instant. And Itōna won’t miss that. I know everything, your weaknesses.”

Sensei narrowly dodged Itōna’s fierce assault that came in during that split-second opening by using a secret move, molting, but he lost several legs.

Even for Sensei, his reaction speed against a first-time attack isn’t that fast.

I caught Shiro in the corner of my eye and his expression had a calm confidence.

“Molting, huh… right, there was that too. But Korosensei, I know molting has a weakness as well. That technique consumes more energy than it looks like, so right after, your proud speed drops and regenerating your body also takes a lot out of you. By my calculations, at this point, your physical performance is almost equal and with my support added, an unstable-minded you is no enemy.”

Shiro fired the light again and Korosensei had his legs crushed by Itōna.

But I know he’s not the kind of guy you can finish off with just that.

“Looks like your leg regeneration is done, but can you endure the next rush?”

“This is the first time I’ve been pushed this far. It looks like a straightforward match-style assassination, but it’s calculated very carefully. I have many things I want to ask you, but first I have to win, otherwise you won’t talk, will you?”

“You still think you can win? Posturing this far is impressive.”

“Shiro-san, there is one thing you forgot to include in your calculations.”

“There isn’t. My calculation method is perfect. Talking to you any longer is a waste of time, do it, Itōna.”

Countless tentacles shot out from the airborne Itōna to pierce Korosensei… except that didn’t happen and instead, Itōna’s tentacles burst apart.

“Oh my, it seems I stepped on a ‘lost item,’ hahaha. If it’s the same tentacles, then anti-Sensei knives work on them just the same. If you lose tentacles, you get shaken up just the same. But Sensei is a bit more bold!”

Saying that, Sensei wrapped Itōna up in his own skin and hurled him boldly out of the school building.

“There shouldn’t be any damage. But your foot is outside the ring. Sensei wins. By the rules, you’re sentenced to death. You can never kill Sensei again. If you want to be ‘revived,’ learn here with everyone in this class. There are things that performance calculations can never measure, that is the difference in experience. Sensei became a teacher because he wants to pass that on to you. If you don’t steal Sensei’s experience in this classroom, you can’t beat Sensei.”

When Korosensei said that, Itōna, driven by fury, attacked again, but Shiro retrieved him.

“Sorry, Korosensei. It seems this kid wasn’t in a mental state where he could attend school yet. It’s his first day as a transfer student, but we’ll have him take a leave of absence for a while.”

“Wait! As his homeroom teacher, I can’t just abandon that student. I’ll take care of him until graduation. Also, Shiro-san, I have a mountain of things I want to ask you.”

“Nope. I’m leaving.”

With that, Shiro carried Itōna and walked out of the classroom.

Sensei reached a hand toward Shiro’s shoulder, but anti-Sensei fibers had been woven into his clothes, so Sensei couldn’t even touch him with a single finger.

And so, the new transfer student, Horibe Itōna, joined our Class E.

* * *

Shiro POV

After retrieving Itōna and leaving the school building, I reported today’s results to the government.

“We failed this time, but it’s not a problem. I already came up with the next plan. Besides, with his personality, he won’t run from that place until March, when the Earth is supposed to be destroyed. And that class… it’s interesting.”

After finishing the report, I disappeared into the darkness together with Itōna.

They still have only seen the ‘light’ side of that target.

Just like white’s opposite is black, where there is light there is always deep darkness.

When they learn that, will they really be able to keep being teacher and students?

* * *

Right after Shiro and Itōna left the classroom, I slipped out without letting my classmates notice and followed after them.

“Hey, can I ask you something?”

“What is it? I don’t have much time either, so if you can keep it short, it would help.”

“I’m not here for a long talk either. I don’t want my classmates to catch on. I’ll get to the point. ‘Are you the creator of that monster?’”

When I said that, Shiro stopped his careless smile and turned serious.

“I’m surprised… who are you, exactly?”

“Aren’t you the one who said you don’t have time? I’m the one asking questions. Answer simply.”

“Fine, the answer is yes. But can you tell me why you think that?”

“It’s simple. The moment Sensei saw Itōna’s tentacles, his expression and your reaction like it was exactly as expected and you know the weaknesses of the tentacles too precisely. On top of the fact that he’s an artificial lifeform, that means you’re either his creator or someone who was involved in that research.”

“I see, pulling that much information out of that conversation, that’s impressive. I’ll honestly praise you for that.”

“More conversation is dangerous, I’m leaving.”

“One last thing. What’s your name?”

“‘Ayanokōji Kiyotaka.’”

“We’ll meet again eventually. I’m looking forward to that time.”

“Good, that’s convenient. I have a proposal for you too.”

Leaving those words behind, I turned my back to Shiro and started walking toward the classroom where everyone should be.

After seeing Itōna’s strength today, the classmates will have realized just how powerless they are.

And each of them will think about what they need to break the current situation and start acting.

Think, hesitate and grow.

For no one else but…

‘For my sake.’

I’ve never once thought of those classmates as allies.

All humans are nothing more than tools.

The process doesn’t matter, I don’t care what sacrifices it takes.

In this world, ‘winning’ is everything.