Chapter Text
Nagisa woke up feeling tired. His memory of last night was… vague, to put it simply. He felt really out of it as he forced his eyes open.
With a groan he slowly pushed himself out of bed. He felt sweaty. Looking down, he noticed he was still in his school uniform. Apparently he hadn’t even bothered to get changed before collapsing into bed last night.
As he got out of bed and rose to his feet, he caught a glimpse of his reflection in the mirror.
Long, blue hair.
It was the first thing his eyes fixated on, and he hated it.
Slowly, bits and pieces of last night, along with memories from nine years prior, made their unwelcome way into his mind.
He had forgotten just how bad it had been living with his mother back then.
Not just the arguments, but the constant control, as though he didn’t have the right to be himself.
The memory made him feel nauseous.
The long hair made him feel worse.
He should cut it.
He wondered how Hiromi would react if he did.
She would probably be mad.
…
That alone almost felt like enough reason to do so.
…Almost.
Nagisa let out a heavy sigh. In the end he decided against it. Now wasn’t the time to act emotionally. Angering Hiromi would only make things more difficult for him.
He wasn’t saying never, he was just saying not now.
With that simple reminder, he decided it was about time that he just get up and get ready for school.
He’ll cut his hair short again, some day.
By the time Nagisa arrived at school, the feeling had dulled. The fresh air and long walk certainly helped take his mind off things. Quickly, he made his way to his desk.
“Morning Kayano,” Nagisa said, greeting Kayano after making it to his desk.
“Oh! Morning Nagisa! I didn’t even hear you walk over,” Kayano replied with a soft chuckle, looking over at him with a smile on her face.
“Say, did you have trouble sleeping last night, Nagisa? You look tired,” She asked, her eyes studying his face.
“Something like that,” Nagisa answered, taking his seat.
“I’ll be fine, don’t worry,” he added a moment later.
“Well, if you say so…” Kayano pouted.
Nagisa watched the classroom entrance as students slowly filtered in. He wanted to speak with Karma about some things when he got the chance.
Finally, after what felt like ages, he spotted Karma entering the classroom. Nagisa pushed himself up out of his chair.
Kayano looked over at Nagisa as he stood up. “Huh? Where are you going, Nagisa? Class is supposed to start soon.”
“Oh, I… just want to speak with Karma about something before class,” Nagisa replied, before walking towards the back of the class where Karma’s desk resided.
“Hm? Morning Nagisa,” Karma said as he took a seat at his desk, where Nagisa was waiting for him. “Need something?”
“Yes, actually. Remember how you said I should… have fun with the whole being from the future, thing?” Nagisa whispered. “Well, I was thinking it over and I think you’re right, but…”
“But~?” Karma drawled.
Nagisa took a deep breath. “I… don’t have any ideas on what to do.”
A silence stretched between them as Karma looked up at Nagisa, shooting him an incredulous stare.
Karma was the first to break the silence.
“Of all the… Nagisa, you have got to be the most boring time-traveler ever.”
“W-well, forgive me for not being an experienced trouble-maker,” Nagisa whispered back defensively, his arms crossed.
“...Ok, but… seriously, nothing?” Karma replied.
Nagisa opened his mouth in preparation to say something back, before being interrupted by Karma cutting right back in.
“Nevermind, obviously you’ve got nothing. Otherwise why else would you be right in front of me asking for advice.”
“Pretty much,” Nagisa replied. “Would you happen to have any suggestions?”
Karma kicked his feet up onto his desk and brought his hands behind his head. He closed his eyes, his face an expression of mischievous contemplation.
“Hmm… I’m not the self-proclaimed time-travellor here, but I’m definitely the right person when it comes to mischief.” Karma opened his eyes and glanced over at Nagisa. “Say, isn’t there a school assembly tomorrow?”
Nagisa pulled up a seat across from Karma. “Oh yeah, there is, isn’t there?”
Karma closed his eyes again as he resumed speaking. “I was planning on skipping it, personally, but you probably already knew that. The only reason they drag E Class down there is to make fun of ‘em. Quite boring, if you ask me.”
“But, putting my plans aside for a moment, you’re from the future, no? I take it that means you already know how they’re gonna go about humiliating E Class, right? You should do something with that, might be fun,” Karma added. “Or… you can keep being the world’s most boring time traveller in existence. Up to you.”
Nagisa brought his hand up to his chin. “Hmm… I mean, I kinda remember it? It was almost a decade ago though. Oh! One of the things they did was ‘forget’ to print out handouts for the E Class… but Koro-Sensei ended up making a bunch of handwritten copies for us.”
Nagisa sat there for a moment, when suddenly his eyes went wide as inspiration struck
“I think I’ve come up with something, Karma,” he began, “What if… I replaced the handouts with fakes?”
Karma looked over at Nagisa. “Hm? Like a bunch of made up announcements and events? Could have some potential, actually. Although, I’m pretty sure the teachers will notice immediately–”
Nagisa interrupted him before he could finish. “I don’t think they will, actually–
A pause.
“Ah, sorry for cutting you off there, Karma. It’s just… I’ve gotten pretty used to how that kind of paperwork looks.”
“Oh, that’s right. You are- were a teacher. My bad, Nagisa-sensei,” Karma drawled. “But hey, at least you’re finding a way to make that teaching degree of yours useful. Bet you didn’t think you’d be using it to pull a high school prank. Almost a shame you’ll have to re-earn your degree.”
Re-earn… my degree…?
The words echoed in Nagisa’s mind. He felt his stomach sink.
The teaching degree that he had worked so hard to earn… it no longer existed.
No, it didn’t exist to begin with, not for at least another seven years!
Nagisa let out a quiet, deflated sigh as the painful realisation hit: he would have to go through university for a second time.
“Class should be starting soon, Nagisa. You might want to get to your seat,” Karma said, interrupting Nagisa’s mental spiral.
Silently, he made his way over to his desk, a headache already beginning to take shape against his temple.
University… again…?
How utterly terrifying.
Would he really have to go through all that again?
With another sigh, he sunk into his seat.
“Nagisa? Are you feeling ok? You look nauseous.” Kayano asked, peering over at Nagisa.
Nagisa let out a small groan. “Yeah, I’m… I’m fine. Just… a bit anxious about something. Don’t worry about it.”
It was currently third period, and Nagisa was sitting at a table with Kayano, Maehara, and Kataoka for science class. They were, along with the rest of the class, all staring at Koro-sensei who was at the front of the classroom, his tentacles clutching an armfull… (tentaclefull?) of various snacks to his chest. He had just finished showing the class how to extract artificial colouring from snack food, before quickly weaving between the desks at Mach 20 to take all the “leftover” snacks.
He was going to keep them for himself.
“He used this as an excuse to swipe snacks ‘cause payday isn’t until tomorrow,” Maehara complained to the table while shooting Koro-sensei an incredulous, judgemental stare.
“Why is a super-organism that can destroy the Earth living paycheck to paycheck?" Kataoka added.
Well… they could do well to pay teachers better…
The class’s quiet muttering however came to a sudden halt, as everyone’s eyes turned to Okuda, who had gotten up from her seat and was now walking towards Koro-sensei, clutching something behind her back.
“U-um, sir…” Okuda stammered.
Can I help you, Okuda-san?” Koro-sensei asked.
Okuda straightened her posture.
“Um… This is poison! Please drink it!” She declared, suddenly thrusting her hands out and presenting Koro-sensei with a collection of vials containing a different liquid each.
If it was any other target, Okuda would've been shot down immediately, possibly in a literal sense as well.
But this was Koro-sensei, Nagisa thought to himself with a fond sigh.
And so, the class watched on as he, almost eagerly, downed the contents of each vial one after the other. Naturally, none of them ended up being poisonous for him.
After finishing off the final vial, Koro-sensei turned his attention back down to Okuda. “Now, Okuda-san. I can’t overlook a student making poison unsupervised. It’s not safe. If you have time later, why don’t we work together on a poison that will kill me?”
Nagisa sat and watched as the familiar event unfolded.
“Making poison with the target?” Kayano questioned.
“I’ll have to ask her about the details later,” Nagisa answered, not that he didn’t already know how things would play out.
Still, there was something he wanted to ask of Okuda anyways.
His eyes glanced over at Kayano meaningfully.
Before Nagisa knew it, the day was over. He didn't end up finding the time to speak with Okuda after school, but last he checked, she and Koro-sensei were still working on the poison together. Ultimately he decided that it would be best if he went home for the day, and ask her for the details tomorrow.
He now found himself standing outside the door to his mum’s apartment. Technically, It was also his apartment, but it felt strange thinking about it like that, so he stuck to calling it his mum’s apartment.
The fact he didn’t feel like he could be himself there only made this mental separation that much easier.
After a final moment of hesitation, he reached out and opened the door, and stepped inside.
As soon as he made it past the entryway, Hiromi greeted him. “Oh, Nagisa, welcome home. I’m glad to see you’ve taken on my advice from last night. How was school?”
He had decided it would be best if he starts coming straight home after school, at least for the next couple of days.
“School was fine,” Nagisa answered, brief but polite as he walked right past her and towards his bedroom.
An uncomfortable feeling twisted in his gut whenever he was around her.
“Oh. I see how it is. Upset because your mother won’t let you stay out late? I’m just looking out for you Nagisa, you know that, right?” Hiromi said, her tone dripping with patronising concern.
Nagisa froze.
“I was young once too, Nagisa, so believe me when I say I understand how you feel, but that’s exactly why I also understand how unsafe it is for a girl to stay out late,” Hiromi added, not even turning around to look at him.
“...Sorry, just a bit tired from school,” Nagisa muttered weakly, lying through his teeth. “...I’ll be in my room doing some studying.”
He walked off, leaving Hiromi behind him and entering his bedroom.
After closing the door, he let out a heavy sigh, and looked at his reflection in the bedroom mirror.
He reached up with one hand, lightly touching one of his pigtails.
He really should just cut it off.
The next morning, Okuda entered the classroom, her face beaming as she held onto a glass round-bottom flask. Inside it swirled a mysterious reddish-pink liquid, the poison she had made with Koro-sensei just the other day.
…Not that it was actually poisonous, Nagisa thought to himself privately.
He almost felt a little bad about letting Okuda be manipulated by Koro-sensei like this.
As if right on cue, the classroom door slid open.
“Speak of the devil…” Nagisa murmured to himself.
“Hm? Did you say something, Nagisa?” Kayano asked, tilting her head in confusion.
“Oh, I was just thinking about Koro-sensei, and then…" Nagisa gestured towards the door. "…There he is."
Kayano gave a light giggle. “Yeah, he can be like that sometimes. It’s like he can just tell when someone’s thinking about him.”
“Okay, everyone. Please be seated!” Koro-sensei said as he made his way to the front of the classroom.
“I brought it, sir!” Okuda announced as she enthusiastically padded over to him, eagerly presenting the flask to him.
“Oh, well done!” Koro-sensei took hold of the flask with a tentacle before uncorking it. “Then I’ll drink it at once!”
Without hesitation, he tipped the flask and drank it. The class fell silent at the loud gulp.
Suddenly, Koro-sensei froze, as his eyes glowed a bright red. A moment later, his body began to glow red with overflowing energy as he let out a sinister, mocking laugh.
“Thank you, Okuda-san,” he said, his voice menacingly low. “Thanks to your concoction, I can advance to a new level.”
The energy flowing out from him intensified, the entire classroom now shaking as it began to fill with a rising dust.
“What… do you mean?” Okuda asked, betrayed and confused.
The powerful energy flowing out of him only intensified even more.
The windows rattled, the glass on the brink of cracking.
A blinding light filled the classroom.
Every sense of every student there was being overwhelmed by the powerful energy flowing out from Koro-sensei.
And then…!
…it stopped.
Anticlimactically.
“Phew…” Koro-sensei sighed, now reduced to a silver goop on his desk. “I actually had you make a tonic that would stimulate my cells and enhance my fluidity.”
A silver blur shot across the classroom.
“As a liquid, I can now fit into the tightest of spaces,” he explained, peeking out from the desk shelf he had managed to squeeze into.
Not a moment later, he shot out from the desk, ricocheting off the walls of the classroom.
“And what’s more, I’m still as speedy as ever! Go ahead! Try and off me!” He taunted.
“What was that poison, Okuda?!” A student asked.
“Y-you tricked me, Koro-sensei!” Okuda exclaimed, her eyes struggling to follow the ever moving silver blur.
Eventually, Koro-sensei came to a halt as he stuck himself into one of the upper corners of the classroom.
“Having the verbal aptitude to deceive others is a vital part of assassination, Okuda-san,” he explained, smiling down at her from the ceiling. “Even the most potent of poisons is wasted if you offer it in such a naive way that your target can take advantage of you.”
Koro-sensei let himself ooze down to the floor. “Nagisa-kun, How would you try to poison me?”
“Huh? Hmm…” Nagisa hummed, turning his attention to Koro-sensei. “I’d probably mix it into a sweet drink you like… and then offer it to you as a special drink I made.”
“Yes, to deceive someone, you must understand their feelings and communicate with them creatively,” Koro-sensei replied as he returned to his normal form and stood back up. “Language is the key to an effective poisoning. Your scientific talent, Okuda-san, will someday be useful to everyone, so, to explain things clearly to as many people as possible, I hope you’ll continue to develop the language skills to poison someone.”
“I-I will!” Okuda replied with an enthusiastic smile.
“Now students, please make your way back to your seats so we can resume homeroom. Unless, of course, someone else has a poison they want me to taste test? I’ll even award extra credit to any student who can find a poison that’ll have an effect on me,” Koro-sensei added with a smug grin as he made his way back to the front desk.
Nagisa took a step towards Okuda. “Hey, Okuda, would I be able to speak with you about something in private after school? It’s about that poison Koro-sensei had you make.”
“O-oh, sure! Although, I don’t think there’s much to discuss, since it didn’t end up being much of a poison in the end…” Okuda replied.
“Yeah, well, I guess it would’ve been a bit of a surprise if it had ended up working. Koro-sensei sure is something…” Nagisa said with a sympathetic smile. “Anyways, I’ll see you after sixth period, then?”
“O-ok,” Okuda nodded.
Compared to the commotion during homeroom, the rest of the day went by quite fast. Sixth period had just finished, and Nagisa was waiting out in the hallway for Okuda. There was something he needed to set in motion, not that he was sure it would end up paying off. Still, it was worth a shot.
“Oh? You’re still here, Nagisa?” Kayano asked as she stepped out of the classroom.
“Hm? Oh, yeah. I wanted to ask Okuda more about that poison Koro-sensei had her make. Even if it didn’t end up working, I figure there might be something we can learn about Koro-sensei from it,” Nagisa explained.
“Oh, and if you see Karma, could you let him know and ask him to wait for me. It shouldn’t take too long and I was hoping to discuss something with him,” he quickly added.
Kayano giggled softly. “You sure are busy today, Nagisa. But don’t worry, you can count on me! The moment I spot him, I’ll let him know to stay put and wait for you!”
Kayano waved Nagisa goodbye as she walked down the hallway and outside. “See you tomorrow, Nagisa!”
“...See you tomorrow, Kayano,” Nagisa replied, waving.
“S-sorry for making you wait, Nagisa-kun,” Okuda said, walking up to Nagisa a moment later.
“No need to apologise. Really, I should be thanking you for staying back for me,” Nagisa replied. “So, about that poison Koro-sensei had you make… I was just thinking, although it doesn’t seem like he can be poisoned, he is still affected by poisons, right?”
Okuda’s face suddenly lit up. “Y-youre right! Even with the regular poisons, although they didn't harm him, his face still ended up transforming, right?”
“Maybe we can’t make a poison that can kill him, but what if we make something that weakens him instead? That way, it might make him easier to kill, even if it’s not what finishes him off.”
This, of course, wasn’t his real goal.
“Oh… You mean something like a muscle relaxant, or maybe a neuromuscular blocker? That might work, b-but… I doubt any ordinary depressants or relaxants would affect him,” Okuda said, her earlier enthusiasm wavering.
“We’ve got a while before the end of the school year, maybe you could try out different things and slip it into his drink to see if it has any effect on him?” Nagisa suggested.
What Nagisa wanted wasn’t something to help kill Koro-sensei. What Nagisa wanted was something that could weaken artificial tentacles. Some sort of tentacle inhibitor.
Something he could use to save Akari Yukimura.
After all, there was no telling how this future would play out.
Even if things had worked out back then, he didn’t know if it would again.
The future is fragile.
It’s dangerous leaving things to chance.
So long as the outcome remains the same, it doesn’t matter how he gets there.
These thoughts bounced around in Nagisa’s mind as he stared at Okuda. He felt a small pang of guilt at lying to her like this, even if only by omission.
But, if there was anyone that would be able to do this, it was her. After all, in just a few years she would grow up to become a well renowned scientist.
So, even if he had to deceive her, he would do it.
“O-oh! That's actually a good idea. A-and I can even try and develop my language skills by trying to trick him into drinking it,” Okuda replied with a smile.
“Thanks, Okuda. Anyways, Karma’s waiting for me, so I probably shouldn't keep him waiting too much longer. Let me know how it goes, by the way,” Nagisa said, waving her goodbye as he made his way to the exit.
“G-goodbye, Nagisa!” Okuda said, waving goodbye back.
To deceive someone, you must understand their feelings, and communicate with them creatively.
Even the feelings his classmates had towards Koro-sensei, their desire to kill him, was something Nagisa could take advantage of to nudge the future in his favour.