A few days later
Class 3-E
(Y/N) POV
Me: So, how was your trip to Hawaii yesterday?
Nagisa&Karma: Fun!
Me: I see.
Yesterday, those two asked Koro-sensei to bring them to Hawaii so they could watch a movie. Since I'm not interested in that movie, I didn't follow them.
Koro-sensei entered the class and greeted everyone.
And yesterday we received a message from Karasuma saying that there will be another assassin will join us as a student.
Koro-sensei: When Ritsu-san and Sara-chan first came, I underestimated them a bit and had dreadful experience, so this time, I'll be on guard.
Me: Just what did you do to him, Sara?
Sara: We cut five of his tentacles, remember?
Me: Oh, right.
Koro-sensei: In any case, I'm truly happy that your number of comrades-in-arms is increasing.
Hara: Come to think of it, do you two know anything about them, Ritsu, Sara?
Sara: I've been trained in different place than them, so I know nothing.
Ritsu: Yep, she's right. But I know something about the new student.
She started telling them what she knows about the new student.
I didn't pay too much attention to her though. But from what she said, she was an overwhelmingly inferior assassin compared to the new student. Oh, and the new student is a boy.
Suddenly our class door open. Everyone looked at the door and saw a man. He was wearing white robe and white mask that cover his whole face except the eyes part.
He then suddenly brought out a pigeon out of nowhere.
Man: Sorry, I must have frightened you.
Me*thought*: Not even a little.
Man:*playful tone* I, however, am not the transfer student. I am his guardian. Well, I'm dressed entirely white, so just call me "Shiro".
I stared at his eyes.
Me*thought*: Hmm?
Shiro noticed that I was staring at him.
Shiro: Is there anything I can help you with?
Me: No, thank you.
I lean against my hand and look out at the window.
Me*thought*: His eyes are eyes of someone that want revenge.
Shiro continued talking for a little bit before calling the new student to sit beside Ritsu.
Shiro:*playful tone* Hey, Itona! Come on in!
Suddenly someone crashed the wall at the back of the class and entered the class and sat at the desk beside Ritsu.
Itona: I... Am victorious. I have proven myself to be stronger than this classroom's walls. That alone is enough. That alone is enough.
Me: Shiro-san, do you never teach him how to use a door?
Shiro: What a sharp tongue you have.
I looked at Koro-sensei to see his reaction.
Me*thought*: Seriously, what's with that half-assed face?
Shiro: Anyway, this is Horibe Itona. Please call him by his given name. Oh, and I've spoiled him a bit, so for the time being, allow me to watch over him.
I stood up and start to walk to the door.
Me: Gotta hit the restroom.
I got out from the class and made my way towards the restroom.
Whilst walking, I looked out at the window.
Me: So it's really raining. Then how come Itona's body completely dry? And his eyes... He's striving for strength. Well, he is still weaker than me.
Timeskip
Class 3-E
After school
(Y/N) POV
We've made a ring desk because Itona wanted to execute Koro-sensei like this.
And when I went to restroom earlier, Itona declared that he's Koro-sensei's brother. Sounds ridiculous? Yeah, I think the same.
Shiro: You must have had your fill of plain old assassinations, Koro-sensei. Let's settle on a single rule for this match. If you take even one step out of the ring, you'll be executed on the spot!!! How about it?
Me*thought*: It's not like Koro-sensei have any choices. If he violates the rule that has been decided in front of everyone, then his credibility as a teacher will decrease.
Koro-sensei: Very well, let's go with that. However, Itona-kun, causing harm to those watching will also mean defeat.
Shiro: Well then, we'll begin on my signal.
He raised his hand.
Shiro: Assassination...
He lowered his hand signalling the match has started.
Shiro: Start!!
In an instant, one of Koro-sensei's tentacles gone.
Everyone except me, Sara, and Karma was shocked. Not because of Koro-sensei's tentacle, but Itona.
Me*thought*: That explains it. His remaining dry in the rain despite being empty-handed was entirely due to those whirling tentacles.
Koro-sensei's face slowly turns pitch black.
Koro-sensei:*mad* Where did you get those!! Those tentacles!!
Shiro: We have no reason to tell you, Koro-sensei. However, with this you should understand. He has different parents and was raised differently. But you and this boy are brothers. Still, that's a quite frightening face you're making. Has this... Brought to mind something unpleasant?
Koro-sensei: It would seem that I need to ask you some questions as well.
Shiro: You won't be able to, seeing as you'll be dead.
Suddenly a bright light came out from inside of his robe sleeve and Koro-sensei's body rigid.
Shiro: When exposed to this pressurized beam at point-blank range, your cell's viscosity will increase your entire body will instantly go rigid.
Itona wasted no time and attacked Koro-sensei with his tentacles. He continued to slam his tentacles to Koro-sensei's body.
Muramatsu: Is he dead?!
Sara: As if.
Terasaka: Look up.
Everyone looked at the ceiling.
Shiro: Molting, hm... Come to think of it, you did have such a trick at your disposal. Even so, Koro-sensei, we are well aware that your molting has a weakness. Itona-
Before he could finish his sentence, I shot one of Itona's tentacles with anti-sensei's bullet.
Koro-sensei: Fufufu, nice save, (Y/N)-kun.
Me: When you made a ring, you also have made one rule. What is it? It's, "the ones who outside of the ring can't help the fighters inside the ring. You can only switch fighters".
Karma:*smirks* But since you have violated that rules, then we'll do the same.
I shot all Itona's tentacles. He tried to dodge my attacks but all the bullets I shot reached him with no problem.
Shiro: You brat...!!
Me: Don't talk like you're an adult. What do you come here for? Revenge? Hmph, what a childish reason. I bet you're the actual reason someone you "love" died. I feel sorry for you, you know? Why? Because you hung up on revenge and can't live your own life.
Koro-sensei quickly trapped Itona with his molted skin and threw him out from the class.
Koro-sensei: I wrapped you up in the skin I molted, so you likely didn't take any damage. However, your feet have left the confines of the ring. It's my win. And it's fair and square. You received help from outside and I also received help from outside. According to the rules, it's the death penalty for you. You won't be able to try and kill me a second time.
Itona pissed off.
Koro-sensei: If you wish your life to be restored. Then please come and study alongside everyone in this class. There are some things that can't be so easily calculated. That's the difference in our levels of experience. I have lived just a little longer than you. And have just a little more knowledge. In this classroom, you need to make time to learn from sensei's experiences or you won't be able to win against me.
Suddenly black tentacles emerged from Itona's body.
Rio: Black tentacles?!
Sousuke: Holy shit! He's losing it!
Itona jumped into the class.
Itona: I'm strong. No one is stronger than me with these tentacles. No one.
Koro-sensei:...
Itona was about to attack Koro-sensei but a bullet pierce him and he fell to the ground.
Shiro: My apologies, Koro-sensei. It would seem that this boy still had such a mindset which would prevent him from going to school. And I failed to assassinate you this time because a miscalculation. I won't make the same mistake again next time.
He said and picked Itona up before walking away.
Koro-sensei: Wait, you have some explanation to do.
He touched Shiro's shoulder and his tentacle immediately melted.
Shiro: Anti-sensei fabric. You won't be able to lay even a tentacle on me. Itona will come back soon. March is around the corner, after all. I will take it upon myself to serve as his home tutor until then.
And with that, he left the class.
Koro-sensei: (Y/N)-kun, do you...
Me: I know nothing about that Shiro guy. What I said to him earlier just my assumption. Nothing more, and nothing less. Anyway, I think you have some explanation to do.
Isogai: Yeah, he's right. What's up with the tentacles that Itona have?
Hayami: You've always evaded telling us the truth, about you. After seeing that, you're not getting out of here without giving us some answers.
Koro-sensei:.... It's really unavoidable... There's no choice but to tell you the truth...
Everyone except me and Sara leaned closer to hear.
Koro: I'm... I'm... I'm actually an artificially-created creature.
Everyone:....
Me&Sara: That's it, I'm leaving.
Koro-sensei: E-Eh?
Sugino: That was expected, duh.
Me: There is no octopus with speed of Mach 20. And you said you're not an alien. And then Itona showed up. It's clear that he was created after you.
Everyone: He's totally right.
Koro-sensei: S-So sharp! What a frightening children!
Nagisa: We're interested in the reason of you being mad earlier. Why were you born... And what you were thinking that led you to our class.
Koro-sensei just quiet.
Me:... I think it's pointless to ask him now. If he blows up the earth, then what we know will be nothing but dust. The only way to make him talk is try to kill him.
Koro-sensei: (Y/N)-kun is right. Try to kill me. Assassin and target. That should be the relationship binding yourselves and I. If you are seeking for the crucial answers that I hold... All of you can do is assassinate me.
He turned around and start to walk to the door.
Koro-sensei: We'll end today's lessons now. Until tomorrow!
To be continued...