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A Yellow Octopus in The World of Heroes

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Izuku is a normal kid. Well, at least until he was four. You see, Izuku is in the minority of the world who does not possess an ability known as a quirk. Some people can fire lasers from their eyes and some can memorise books with a blink of an eye. Izuku, on the other hand, wishes he had at least something.


He was shunned from society, bullied or left alone. He used to have a friend, Bakugou or as he used to call him ‘Kachan’. He lost that cutesy nickname when he was four. But, even so, his mother kept sending him to the same schools as him. He was forced to become Bakugou’s shadow.


That was though, until his second year of junior high. Why? I’ll tell you.


It was a normal day of school at Aldera high, the birds were singing but inside of Izuku’s mind it was storming. He was totally done with everything. The bullying was getting too much. What used to be simple words turned into quirk-powered punches.This day though, was partially bad. He had managed to score the top student in his class for the end of year exams.


Bakugou had come second.


Now Bakugou did not like this at all. He gathered his lackeys (Extras as he calls them) and formulated a plan.


They waited for Izuku to reach the stairs to exit the school then in a blink of an eye, they pushed him with all their might.


Izuku let out a sound of distress, dropping his books and stumbling down the stairs, reaching his arms out to break the fall. A loud snap echoed throughout the hallway. It was silent. No one dared to make a sound.


Horrified, Bakugou and his lackeys make their exit, running in the opposite way.


Izuku stared at his arm, shocked. His arm bent in the opposite way. How was he gonna hide this?


Long story short, his mother took him to the hospital and took him out of Aldera and switching to Kunugigaoka. It was easy though, being the end of the year. That’s how he found himself in this situation, Staring at a bright yellow octopus who was grinning widely. 


Despite having great grades he was still bumped down to the ‘E’ class. Also known as the end class. Because apparently life hated him. Anyways, back to the elephant in the room. Or should I say octopus?


“Nice to meet you!” The being said. “I’m the one who blew up the moon!”


That’s right. Just a while ago the moon had been blown up. The moon, now named the crescent moon, was shining bright in the sky despite it being the middle of the day.


“I also plan on blowing up the Earth next year!” It continued. “Seeing as I’ve become your homeroom teacher, I look forward to working with you!”


The creature smiled wider, if that was even possible. It was creepy if Izuku was being honest. A man standing next to the octopus stepped forward.


“I am Karasuma from the Ministry of Defence. We work with the Hero Commision. First of all, I would like you to understand that what I’m about to say is classified government information. Now cutting straight to the point I would like you to kill this monster.”

Gasps filled the air as the man- Karasuma finished. Izuku’s mind was in a twist. He wanted to become a hero. What kind of hero kills others? What kind of hero kills anyone? In the midst of his internal panic, someone with blue hair nudged him.





Quirk: Calming voice

When talking to someone she can calm them down. If her voice is used in a different tone, her quirk has different effects. It’s great if she wanted to ever do acting as a job!


Quirk drawbacks:

Always active, causing her to sometimes strain her voice.


“Hey,” Kayano said in a soft voice. “Calm down. We can get through this. Anyways, us green-haired people gotta stick together!”


She smiled as Izuku relaxed. 


“That’s right!” Izuku replied. “If we kill the octopus we save the whole world. Making us great heroes!”


Izuku and Kayano smiled as they turned back towards the chalkboard towards their teacher.


“The reward for success in killing this creature will be 10 biliion yen. It is an appropriate sum after all people usually don’t like working in assassination.”


Eyes widened as the reward was revealed. 10 billion yen was a lot of money ($131,447,600 aud or $95,570,320 usd), you could do a lot with it. Both good and bad.


After a quick explanation the government workers rolled out some carts filled with guns and green, flimsy knives. 


“And remember,” Karasuma chimed in. “This must be kept a secret from your friends and family.”


Izuku looked around his classroom. Mixed reactions filled the faces of his classmates. Some shocked, some surprised and some with bloodlust filled smiles. 


This was going to be a long year…


Chapter Text

Izuku was honestly kinda shaking. They had been handed guns and knives that seemed to be useless. He had gathered with his class after the first school day had ended. Izuku, being the shy kid he was, decided not give any input when his class started talking about assassination plans.


The next day arrived in a flash, Izuku being too afraid of the consequences to tell anyone about his first day of school.


They gathered in the classroom early, waiting for their teacher. Guns lay beside their desks. It was oddly quiet for a classroom. From Izuku’s experience it was usually filled with chaos before the teacher got there.


Eventually, the students heard a slimy sound of their teacher in the hallway. Nodding to each other, they got in position.


“Ah,” The creature began. “It’s now time for role cal-“


The octopus was cut off by the class standing up. Simultaneously, they fired their guns. A barrage of bullets sprayed around the classroom as all the students tried to land a shot on their teacher.


Their teacher though, was moving at the causal speed of Mach 20. You know, as you do. By moving at such a speed he managed to dodge all the bullets with ease, all while taking roll call.


“Well, if you want to kill me you’ll have to do better than that! Now! Clean up this mess! This assassination should not affect your studies!”


Izuku’s class just sighed in defeat as they cleaned up the anti-sensei bullets. Their sensei had shown them the devastating effects said bullets and knives had on him mere moments ago. Saying something along the lines of him becoming like Tofu, the weapons slicing right through him.


“Hey! Nagisa, Midoriya!” Terasaka said. “Let’s work on an assassination plan!”




Quirk: Intimidation

When wanting to talk with someone, his intimidation overpowers his senses. This makes him snarky and somewhat aggressive.


Quirk drawbacks:

Always active so his aggression continues to show, his intelligence is also lowered. With proper training he should be able to turn it off.


Despite not wanting to go, Izuku followed him with Nagisa. He could see that he was in the same boat. Sighing, the rainbow-haired children followed Terasaka and his friends.


“So,” Terasaka began. “You’ve both been observing him, haven’t you?” 


Izuku and Nagisa looked at each other, notebooks in hand. Blinking at one another, they both turned to their pages on their sensei.


Nagisa Kun


Quirk: A snake eyes


When holding a weapon, Nagisa can mask his movements and paralyze his opponents when  close enough. His eyes are also a permanent mutation, causing him to see little details.


Quirk drawbacks:
If he uses his quirk for too long, his movements become sloppy and loud. The paralysis effect stops working, straining Nagisa’s eyes.


“Our sensei is some sort of unkillable teacher. He displays different moods depending on the colour of his face.” Nagisa and Izuku began. “The yellow face he usually wears is his neutral face. When it’s striped green, he’s confident. It also differs when a student gets an answer either right or wrong, being an ‘x’ or an ‘o’. And what’s very interesting is that after lunch time-”


“Yea I don’t need to know that.” Terasaka interrupted. “When he has his most carless face on, one of you will stab him.”


Terasaka handed an object to both of them, whispering something to Nagisa. Without thinking, Nagisa grabbed the object and knife before heading back inside.


After lunch, Izuku’s Sensei was explaining the task for the lesson. They had to make poems and end them with the word tentacles. 


“The flower petals fell like coloured snow. The vines withered up from the ground like tentacles” Their Sensei said, giving them an example. After some time Kayano spoke to the teacher.

“Umm, Sensei? What should we call you?” She asked.


“Well, Kayano why don’t you think of one for me?” Their Sensei replied.




Izuku had noticed it, the octopus teacher had been slow to respond. Nagisa must have seen it too because he took the opportunity to stand up from the desk and go to their teacher. A knife was positioned behind the piece of paper Nagisa was holding. 


Everyone held their breath as Nagisa walked over to their teacher with a small smile on his face. It was kind of strange, someone was about to attempt to assassinate their teacher and they seemed to be happy, not thinking about the actions of doing it.


“Ah, Nagisa. Have you finished already?” Their smiling teacher asked.


Nagisa gave a small nod before rushing in to stab the teacher. 


It didn’t work though, the octopus simply just stopped him with his tentacles with ease. He shook his head in disappointment.


“I’ve told you already, if you want to assassinate me you need a better-” Their teacher was cut off by Nagisa hugging him. “-Plan.”


Terasaka gave a large grin as he pressed a button on a remote, causing a huge explosion. Everyone shielded their eyes as a rain of ‘Anti-sensei’ bullets flew around the room. Terasaka gave out a massive chuckle, explaining his plan and saying that he would pay for Nagisa’s hospital bills with the prize money.


Walking over, Terasaka stopped, looking at the weird sheet that covered Nagisa. Izuku did what he did best, he started analysing it to his best ability, eventually coming to the conclusion that it was the skin of his teacher.


“I actually shed once a month.” Izuku heard his teacher say. His voice echoed throughout the silent classroom. “Good observation, Midoriya! But, I don’t like doing it. The only reason I did do it was so Nagisa wouldn’t get hurt.”


And that’s when they were met with a new emotion. Pitch black, pure anger.


“Terasaka, Yoshida, Muramatsu! This was your plan, wasn’t it?” 


“What!?” Terasaka screamed in defense. “It was all Nagisa and Midoriya’s idea! All I did was press the button!”


Their teacher rushed out of the classroom, returning moments later with everyone's house addresses. 


“It was against the deal for me to harm you, my class but, I could go after all your friends and families.” The octopus grinned before turning an orange colour with a red ‘o’ on it. “I must say Nagisa, you looked so calm and natural up until you grabbed me. And Midoriya! You have some great analysis and I wouldn’t be surprised if you were told to contribute to this plan against your will. After all, you seem to have a great heroes complex.


The rest of you, however. Didn’t take any regard for Nagisa’s safety. So, no more assassination attempts that put your lives at risk, understood? Good."


“A teacher who can’t be killed.” Kayano started. “Sensei means teacher and koro senai means unkillable. So what about the name Koro Sensei?”


Everyone agreed with the name. It was perfect for their teacher. 


They are assassins. Their target is their teacher. Class 3-E, the assassination classroom had just begun. It was going to be a long year...