Note: This is an Assassination Classroom AU, and I wrote it assuming the reader knows about a certain twist from later in the story. The bottom line is that if you have no idea who Aguri Yukimura is, I'd advise to not read any further if you don't want to be spoiled.

A very special classroom

Prompt: "I've got my books - now I'm ready."

-Hey, I brought those books I told you about yesterday. I'll just leave them here so you can look at them later.
Tuuri put the books on his desk with her usual cheerful smile, and skipped back to her seat. The difference between the smile she showed when she was genuinely being nice and the one she showed when she had any kind of ulterior motive was smaller than it used to be, but still there, and big enough to be noticeable to someone who had younger siblings of their own. But it also caused the young woman to remind him of the fact that he would never get to see any of his younger siblings ever again. They wouldn't recognize him if they saw him anyway. If only he hadn't been desperate enough for a job to accept being a test subject in that shady government laboratory. He noticed the covers of both the books that Tuuri had brought him looked quite new for those of items that she was supposed to just happen to own, and that Reynir could be quite crafty with the special material that was harmful to him, but might as well be rubber to ordinary humans. He brushed one of his upper tentacles against the spines and covers of both books, but nothing happened. Physical contact with the special material usually made his skin melt.

The bell signaling the beginning of the class rang. The roll call happened without anyone making a move. He still remembered the first one that had happened after Sigrun had taught the students how to use guns. All twenty-six of them had tried to shoot him with special material pellets at the same time, but he had been able to dodge them all, thanks to the sheer speed at which he was now able to move. They had given up after everyone had run out of ammo. First period of the current day was math, and he decided to start it with a problem that would leave him with time to look at one of the books that Tuuri had brought. He opened the first book, and started reading it. It was quite interesting, indeed. Um… he had never considered that aspect of the issue.

He suddenly had a new issue to address. He was about to grab the handkerchief he usually used to pull special material weapons out of people's hands, only to realize that it was gone from its usual spot. Thinking fast, he decided to settle for gabbing Lalli himself by the waist, hoping the surprise alone would be enough to make Lalli drop the special material knife he was holding. True to himself, Lalli held onto the knife, and promptly used it to slice off the part of the tentacle holding him. The loss of his tentacle slowed him down, but he was still more than fast enough to dodge Sigrun's own attempt at stabbing him. Just as it happened, he remembered where he was keeping his other handkerchiefs, grabbed one out of his desk drawer with his still-intact upper tentacle and used it to grab Sigrun and Lalli's knives in one swipe.

Lalli response was to walk back to his seat, and the math problem. To think that Tuuri had pleaded with Sigrun to get him transferred to another class, back when the students had first been told that their new teacher needed to be killed within the following year, and that they were going to be drafted into the effort. Lalli was now one of Sigrun's favorites, and Tuuri had picked up on his talent sufficiently to have him hold the weapon while she was the one who came up with a plan. Sigrun, meanwhile, gave him a dejected look:
-You were really about to get yourself stabbed because you got distracted by a book? You're kind of lame for a weird monster who's threatening to destroy the planet, Big Guy.
He moved away from his desk just in time to avoid the spray of special material pellets coming out of the second book Tuuri had left on it, which had suddenly opened on its own while Sigrun was talking to him.

xxxx

Tuuri was tinkering with the fake book's timer at her desk, while Reynir and Emil were tending to the octopus in a big tank in the back of the classroom. Despite the fact that his very existence was meant to be top secret, students of the class had muttered about octopuses in the presence of outside people too many times, and the cover story had ended up being that the class had an actual pet octopus named "Big Guy". While seeing for how long they could convince outsiders that they had a non-existent pet octopus would have been both amusing and a good way to test everyone's ability to lie convincingly, Sigrun had quickly decided that the lack of actual pet octopuses in the class was too much of a risk, and had gotten "Little Guy" installed in the class overnight. The animal had unfortunately quickly turned into a perfect tool for Sigrun to throw a few jabs at him, but had also fortunately revealed that Emil completely lost his aversion for anything that got his hands dirty when it came to caring for animals. Reynir, meanwhile, had had to move far away from a family farm to attend the school, and was missing the animals. It also gave them something to do together, as each of them being good friends with one of the Hotakainen cousins had put them in the same social circle, but left them with painfully little else to do or talk about when left alone with each other.

Lalli ran into the classroom:
-Onni had to come by here for work. He wants to see the fake Big Guy. We need to hide the real Big Guy and all the killing things.
In a split second, he had re-arranged the teacher's desk so it looked like Sigrun had been the one using it, and hidden himself in the secret storage room for the special material weapons. Not exactly the safest place for him, but it was the room that was best hidden from people who weren't part of the class. He heard a knock on the trap door:
-Hey, do you mind if I come in? Onni used to be one of my uncle's subcontractors, so things tend to get more awkward than they need to when we're in the same room.
His first instinct had been to tell Emil to go hide where he would have hidden if that secret room hadn't existed, in case someone from outside the class came looking for him. Letting Emil in would put one of the students who was the most interested in the hefty reward for killing him in the same room as him and plenty of tools to do exactly that. However, Emil's words intrigued him, so he permitted him to enter.

Onni looked at the aquarium:
-So this is the famous octopus. He's a big guy, indeed. It must cost quite a lot to feed him.
Sigrun answered the best schoolteacher voice she could muster:
-A shrimp breeding pool was being set up for the school as a learning tool around the time we got him. We don't actually spend too much extra money on that.
Even though it was a private school, it was still a relatively affordable one. Yet, the higher-ups had insisted on installing a regular food source for the octopus, and it had been very hard to explain to parents or whoever else was paying for tuition. On that subject, Sigrun realized that the Hotakainen family must have bounced back from Onni losing his biggest client a couple years ago quite fast for both Tuuri and Lalli to be attending the school. Sigrun decided to keep the question for later, as she was currently supposed to play the role of a teacher keeping an eye on the students who were spending the second half of the lunch break in the classroom. And resist the urge to pocket half the Viking-themed trinkets Big Guy had left on the desk to take them home before he put them back to wherever he had been hiding them so far.

-Their family is pretty much used to function in the wake of a mishap. Our family business collapsing right when theirs was starting to do well is only the most recent of them. When all the other subcontractors were still bummed out by the loss of my uncle's business, Onni was the only one able to think straight enough to notice there was a way they could help each other if they acted fast. The arrangement he offered kept him and a few other subcontractors from falling prey to people taking advantage of the situation. They are all doing quite well, now. But considering you're here, their next mishap may not be that far away.
He didn't point out to Emil that he was in a good position to try fixing that. Whether he made use of the fact before they both needed to go back to class or not, he was going to learn a valuable lesson.
-Is this the reason Lalli was never properly examined until recently?
Emil stayed silent for a few moments before speaking:
-I never really thought of that. My impression was that it was just routine for the teacher we had before you to make sure whatever had gotten us sent to her class wasn't part of a bigger problem. She talked one-on-one with me when I came here, too. But when she talked with Lalli…
In his mind, Emil's voice shifted to another one, telling the exact same story, from a different perspective:
-From what I can tell, his behavior just kept getting explained away by whichever tragedy was the most recent. I don't think someone has actually listened to him in his entire life, and he was having great trouble putting his thoughts into words while I was speaking with him. He and one of the students already in the class turned out to know each other, but…
With some effort, his mind managed to shift back to Emil's voice in the present time:
-I had been quite mean to him at an office party back before my uncle got into trouble, so I went to apologize to him. Next thing I knew, I was the only person in the entire class to be somewhat friendly to him, and I couldn't bring myself to leave him alone up until Tuuri got transferred here.
He already knew that Tuuri was a more recent transfer than Lalli; both of them had started on the same day.

-Ah, don't worry about this this. I quickly figured out that Tuuri had let her grades drop on purpose because she was worried about Lalli being here. Many of the kids are here because they are having actual trouble with the schoolwork. Having her here lets more of them get help at the same time. This class is intended to help them bounce back, after all.
This was the official reason the class existed, but Sigrun didn't buy it. As far as she could tell, its true purpose was to sweep the students that risked giving a bad image of the school under the rug, all while continuing to collect their tuition fees. The practice of having the students help each other on their weak subjects, while the teacher tended to those who were having trouble across the board hadn't been as much a program as a necessity. The principal was just lucky that there were a few students who had actually been stimulated by such an environment, rather than seeing it as a blatant sign the school had just plain given up on them. However, she was quite sure that the fact that the other octopus-like creature could move at high speed and was surprisingly dedicated to actually teaching his students was the only reason they were currently getting any kind of real help. Onni spoke:
-About that. I've been told that you are refusing to let Tuuri help Lalli, and instead making her tutor some country boy. This is obviously not working well for either of them. Arguments are breaking out in our household much more frequently then they used to. Would you mind letting them work together, at least from time to time, to see if it helps things?
Pleading for Lalli to be transferred to another class had been only one of the many ways Tuuri had tried to take Lalli's activities in the class in her own hands, and had all around acted as if the fact that she had gotten herself transferred to the class for the sole purpose of "making things easier for him" automatically entitled her to have her requests fulfilled. Big Guy's response had been to have her tutor Reynir and limit her hovering over Lalli as much as he could, to get an idea of how Lalli dealt with things on his own. Putting them in a situation in which they were no longer obligated towards each other, but in a position to see each other interact with other people and their schoolwork, had made their relationship more complicated than it had been before. They were both finding out new things about each other every day, but at the same time were having trouble shaking off the habits that had engrained themselves over their entire childhoods. Many of those habits were now in that difficult limbo where the old way of doing things was agreed upon to be wrong, but the new way had yet to be completely worked out. It was most certainly following them at home, and she couldn't blame Onni to be taken aback if he was used to them at least outwardly getting along. Unfortunately, their cooperation from just this morning concerned something that they weren't supposed to talk about with outsiders to the class. She suddenly realized that she had the perfect answer for Onni:
-You know what? There happens to be projects on which the students will need to work in pairs coming up soon. I could have them work on theirs together. If they don't mind, of course.
Tuuri and Lalli both nodded from behind Onni's back, each of them looking somewhat sincere. The first bell for the end of the lunch break rang. Sigrun was very happy to hear it:
-On that subject, class is going to resume in five minutes. We are a little far away from the main building, so I suggest you get going if someone is expecting you after the lunch break is over.

They had now been sitting in the dark room in silence for a decent amount of time, and Emil had yet to make a move. He knew because he had been monitoring the room all this time. Fortunately, he had found the perfect way to keep himself busy. The first end of lunch bell rang, prompting Emil to speak.
-Sigrun will probably use this to kick Onni out of the class if he hasn't left on his own yet. Would you mind going out first to make sure that he's actually left? You can be in and out before he even notices you're there, right?
-Of course I can. In return, I'll just ask you to please watch your language.
During the brief instant for which the room's trap door had to be open for him to leave, light from outside poured in, showing Emil the dozen of special material grenades – his weapon of choice – that he had silently placed within a literal arm's reach of the young man during their conversation. Emil didn't let a full swear out, at least.

xxxx

The exercise was more complicated than the last one Sigrun had imposed upon them during the previous "Physical Education" session. In pairs of two, they were supposed to "Kill" as many other pairs as possible, while avoiding getting "killed" themselves. Lalli wasn't the only student in the class who was good with a rifle, but the distribution in proficiency was still such that people usually ended up in Lalli's range for an accurate shot before Lalli was in theirs. Tuuri's job consisted mostly of watching out for people coming in from his blind spot. While on lookout, she couldn't help thinking about how Lalli had never done that well at school, and this, of all things, had turned out to be not only what he was good at, but something in which he was better than her. The only thing softening the blow was that physical activities had never been her strong suit. She and Reynir had been among the six first to "die" in the two previous exercises similar to this one the class had undergone so far. The second time, the four other "dead" students watching the rest of the exercise unfold had ended up commenting about how "creepy" it was that Lalli had taken so easily to this class they were officially not supposed to have. One of them had gone as far as to outright tell Tuuri that Lalli was probably going to kill both her and Onni without warning someday. Both Sigrun and Big Guy were doing their best to make sure each of them understood the full implications of what they were learning to do, but it had been hard for Tuuri to tell how much of it all Lalli had actually understood. They were forbidden from trying to kill Big Guy if there was any risk of collateral damage that would put someone else's life in danger. Their own friends and family, alongside the personnel and other students of the school, were off-limits as well. Those rules were clear, and Lalli would follow them. But a small part of Tuuri nonetheless had doubts about what would happen if Lalli ran into a complete stranger acting hostile towards him, and he couldn't run away. She couldn't believe how radically the exact reason she didn't want Lalli walking around alone had changed over just a few weeks. She suddenly noticed signs of someone coming. She reflexively changed her position on the tree branch one which she had been sitting, only to realize too late that her leg had gone numb. Lalli noticed her starting to fall, but didn't manage to catch her, not that it would have done any good: Lalli didn't have much muscle, and she was quite pudgy.

xxxx

Tuuri was starting to wonder if there was anything Big Guy could not do as she examined her newly bandaged wounded shoulder.
-How am I supposed to explain this to Onni?
-You are all officially doing parkour. You fortunately suffered something that can be explained by that.
She suddenly realized that she was alone in a room with Big Guy. It was the perfect opportunity to share her thoughts about Lalli, so she did.
-Your cousin needs something he's good at in his life more than you realize. He hasn't gotten used to what comes with it quite yet, so it may not be a good idea to take it away anytime soon. As for the future, I will point that as of now, he has shown no more interest in pursuing such activities in the long term than you have. And if it can reassure you, Sigrun has been keeping an eye on him, and has yet to see anything that would make him a danger to himself or others should he actually choose to pursue a line of work that requires proficiency in fighting or weapons.
-How would I explain that to Onni? What happened to our parents and Lalli's has made him extremely prone to worrying about us each time we do something somewhat dangerous. If Lalli ends up with a job where he has a higher than usual chance of getting badly hurt…
-It will be his choice to make as an adult, if he decides to choose this path. You and your brother can try talking it out of him if it ever happens and if you wish. If that doesn't work, the best you can do is support him. Good things to go back to can make the difference between hanging on and letting go in the worst times. In such moments, I'm sure he would rather have a supporting family than one constantly pestering him to change careers. Both you and Reynir are excused from your tutoring session tonight. Go home and get some rest, it will help you heal.
Tuuri nodded and got off the stool on which she had been sitting:
-I just need to get…
Big Guy used the very tentacle that Lalli had sliced this morning, now regenerated, to open the small infirmary's door and reveal a grinning Reynir, holding both their bags and their raincoats:
-Thought you could use a little help. And since I live in the building next-door to yours…
Reynir helped her put her raincoat on, and she noticed it was not actually hers, despite the fact that it had looked identical to it at first glance. She was about to ask Reynir whether he had mistaken someone else's raincoat for hers when she remembered what he had been working on; he had mentioned that he had yet to find a way to make the stuff look like ordinary fiber, which was the reason he was sticking to garments that were supposed to have its natural texture in the meantime. She wondered if Big Guy had noticed yet. She would find out tomorrow.