Assassin Hero!

Explanation

"Let me tell you a story," Nezu said, somehow conjuring up two cups of tea.

Aizawa still sat there, dazed at what Nezu told him.

Nezu blew up the moon?

More importantly, Midoriya and a whole fucking class might be traumatized and the government knew this yet didn't do anything?

"I thought that the moon was blown up by a high-ranking villain."

"Well," Nezu responded, "one could consider them as a high-ranking villain, especially since what they did was certainly endangering society."

"What did they do?" Aizawa pressed.

"That's why I said I was going to tell a story! Now drink up your tea. Let's see," Nezu put down his cup and started to remember.

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Once upon a time...

"You vulgar swine!"

"Actually, I'm the principal of UA," Nezu said.

"Shut it! You are in no position to speak back!" a man in white said on the other side of the glass.

"Hey now, be nice," another person on the same side of the glass as Nezu began.

"And you! How does it feel, 'Reaper', to be reduced to this??"

He laughed, that is, the man in the lab coat, who then choked on his own spit and started to have a coughing fit.

"Sure, buddy," the so-called 'Reaper' said. "Sure."

The lab coat man growled before looking around frantically. "Where is that fucking bi - "

"I'm here! And so are the reports you told me to bring!"

A lady in a similar style lab coat ran over, waving several papers around.

She stopped right in front of him, catching her breath before handing the papers to him. "Here you are - "

The man's right hand travelled from Point A to Point B. Her face, once unmarred, now sported a large, red handprint.

"What a fucking misery I have to be married to you. Determination. Ha! Even a fucking sloth moves faster than you, perhaps I should just do away with you. At least then I'll be free of your stupidity." With that said, the man walked away with flair, leaving the poor girl behind.

"Wow, how rude of him," 'Reaper' said, rolling his eyes.

"What?" she looked over at him. "Oh, that's nothing."

"If that's nothing," Nezu piped up, "then this must be a rather toxic relationship. It's an arranged one, isn't it?"

"I - how did you know that?"

Nezu hummed. "He was rather adamant about wanting to end the relationship and marriage. Besides, you seem smart."

The girl flushed.

"What's your name? I think that I wouldn't want to keep calling you 'girl' the entire time I'm here."

"Uhm," she looked around quickly before saying, "Yukimura. You can call me Aguri. I have a sister."

"So, Aguri," Nezu said, "are you working here because your fiance forced you to?"

"I - "

"You don't seem the type to partake in a highly illegal job, especially when you have a family," Nezu said. "Am I right?"

"I - "

"Aguri! Get over here!" someone yelled.

Aguri looked back apologetically. "I'm sorry, I have to go!" She then raced off to another part of the lab.

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Now...

"She was a sweet woman," Nezu said as Aizawa's mind raced. "Aguri made sure that we were alright, even risking herself to talk to that disgusting excuse of a human. Perhaps that's why we all bonded together, as well as why the person with me fell in love with her."

"He what?"

"Yes, fell in love with someone with already a fiance. Like a rather unusual love story. She didn't know how to break it to her father thag she didn't want the engagement, so there was a bit of a pickle."

"What was the man's name?" Aizawa asked.

"He didn't have one. So I called him 'Reaper' which then shorted itself to 'Reap'."

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Once upon a time...

"You're in love with her, aren't you?"

The man with him, who used to be so stoic when they first met, stuttered. "I-I-I don't know what you're talking about."

"Oh, please, it's very obvious. Yesterday, when she bent over to get something, you saw her bra inside her shirt and abruptly had a nosebleed." Reap's face turned rosy red.

"I perhpas might," he looked away with a pout, twiddling with his fingers like someone who was caught stealing from a cookie jar.

A click clack of shoes echoed and the two looked over to see a distraught Aguri.

"I'm sorry," Aguri said. "I'm so sorry I couldn't convince him."

"Convince him what?" Reap asked.

Aguri looked at Nezu. "You're being sent to the moon with a mouse. You're being injected with antimatter."

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Now...

"So if you were injected with antimatter," Aizawa began, only for Nezu to cut him off.

"No, I wasn't injected with it."

"How?"

"I managed to convince a rather forgetful man that it was only for the mouse to be injected. I then sneaked back on the rocket, flew down to Earth, and went back here," Nezu explained. "I still like to think that the moon blowing up was my doing because the antimatter the mouse had was what was supposed to be for both of us."

"But why hasn't this come out on the news?" Aizawa questioned. "Those vultures wouldn't want to miss a story like this."

"Oh, I tried. But guess who was behind this scheme? One who could shut down anything and everything?" Nezu's eyes sparkled dangerously.

"The government."

"Worse. The Hero Commission."

"What?? Why?"

"The fiance, who I now know as Yanagisawa Kotaro, was planning on making something that could defy the laws of physics, a super human, if you would, better than All Might's power. The Hero Commission wouldn't hesitate with that. Where do you think the pay and funding came from? However, as soon as Reap escaped, they immediately stopped."

"He escaped?"

"Yep. And now was to be assassinated, for if he wasn't, then the Earth would explode a year later. He wanted to be a teacher, just like Aguri was when she wasn't at the lab, specifically Class 3e, Aguri's old class."

"Class 3e?"

"Midoriya's old class. He was smart, yes, but being quirkless, he was shoved to the bottom of the heap. Sad what discrimination can do, yes?" Nezu sighed.

"So when you said a whole class was involved, you meant this class, right?" Aizawa said.

"Very good, Aizawa. Yes, an entire class was involved in killing Reap, who had become powerful since he had escaped with antimatter in him. Yanagisawa succeeded in making a super human. One that would kill Earth if not assassinated."

Aizawa's breath hitched as Nezu finished.

"That entire class was funded by the government and a prize of 10 billion yen if the newly dubbed 'Koro-sensei' died. Awful things people do in the dark, yes?"