The Principal
Kai took the envelope in his hands. It was heavier than expected, even though he knew that there was something unexpected in there.
Opening the envelope, he slid the contents out onto the table. A thick packet of papers that matched the paperwork that Ayako had. And two metal hockey pucks with an indent in it.
"What is-" Ayako got cut off as one "hockey puck" activated. With a light whirr, the bottom of the indent lit up, and a screen was projected into the air. Startled, both Kai and Ayako just let their voices trail off revealing their first thoughts.
"He's kinda cute with that little suit and that face."
"Is that a rat?"
"Don't be rude."
"Hello, Kaisei Oguchi. I am Principal Nezu," the white rat(?) in a suit introduced himself. He was sitting on a couch in the middle of what seemed to be an apartment. "And as principal of UA," he continued, "it is my pleasure to welcome you into Hero Class 1-A. You had the highest score we have ever had, with 120 points. Of those, as I'm sure you already know, 75 were from destroying robots around the arena. The other 45 were from the hidden 'Rescue' category, where our teachers were judging your performance, and your showing of heroic ideals."
Principal Nezu sighed, and hung his head, clearly in thought. After a short pause, he spoke again.
"I want to congratulate you, as your presence will undoubtedly be a… memorable moment in UA's history. However, and this is why I am shooting this video from my apartment, I must confess my surprise at your entry. With your Quirk, you could have gotten in on recommendation. In fact, two of your classmates will be ones who have gotten in that way.
"It didn't take much research to look into you. Quirks are, after all, a matter of public record. However, it looks like you registered yourself as 'Antenna Hair' until one month ago. It didn't take using my Quirk to figure out that was a lie. You showed too much skill and tactical knowledge with your… creatures to have only three weeks' worth of mastery. You have been hiding yourself. And then you showed up at UA with a bang."
"I know why you have been hiding. What I don't know for sure is your intentions. I was a Pro Hero then, when your mother reappeared."
Ayako froze, feeling a cold wave sweep over her brother's emotions. She tried hard not to look at him, fearing what she would see. Still, she managed to compromise and look at him without turning her head to give herself away. What she saw was both saddening and relieving. While his face did have a bit of anger, it was dominated by grief. Luckily, it was not the other way around.
"I am sorry I was unable to do more for her at the time," Nezu said, bowing his head. "I didn't have enough weight in those days to influence the others either. It wasn't easy, being an animal with a Quirk who wanted to be a hero."
"Although, even after all this time, I never was able to find… them, and hardly anybody wants to acknowledge their existence, either." Kai nodded in understanding of two things. The first, that his revenge was going to take time. his own efforts to find those that had brought ruin to his mother were not going to be easy to find. The second being that Nezu was aware of many things, including the possibility that he might be overheard through this message. Or even at the moment of recording.
Well, he especially wouldn't want a panic.
"During your time here at UA, I will do my best to help you and work for your safety as we do for all of our students. However, your very presence presents a significant risk to everyone else. And, if I might be frank, you yourself might pose a threat to everyone's safety. You know that. In return for helping you and allowing you to study here, I would like to know everything you know about your past and your Quirk. Just in case any… unfortunate situations were to rise up."
"I will not force you into anything. Nevertheless, I would appreciate it if you would cooperate." Principal Nezu smiled. "Well, I hope to hear from you. In your acceptance packet is my personal information. Please use the other holo-disk for your response. I find that they are rather secure when used to record things directly. It will only play for me at my address, not anywhere else. So feel free to tell me anything you think I ought to know."
"Welcome again, your Hero Academia awaits!"
With a last bow goodbye, the hologram winked out of existence. For a moment, Ayako and Kai were silent, thinking about what Principal Nezu had said. Ayako felt a little uneasy. Nobody had to give out the details of their Quirks. Even though the law required everyone to register their Quirks publicly, all that was required was a name and a basic description. They didn't need all of the details, like mechanics or weaknesses. It was already somewhat intruding on their privacy as it was. Nezu's request was too much in many respects.
Meanwhile, Kai's thoughts were much more accommodating to the request. After all, he had felt a lot of pressures from his Quirk. The bloodthirsty urges of the zerglings bled through to him every time he summoned them. And there were more things that he could summon, he just knew it. His Quirk said so. In the same way, he knew that every time he pushed further, summoned something bigger and stronger, or just called on their power en masse, that pressure would increase.
If it ever overpowered him… he didn't want to finish that thought. He was already determined to avoid that no matter the cost. Even if there were other paths, safer paths for him, he couldn't just…
"Ayako, I'm going to do as he says; I'll tell him everything."
"Onii-chan, you shouldn't! He's asking too much! You heard him! He thinks that you are a threat, when you have never wanted to hurt anyone! I think I misjudged him when I thought he was a cute little Mickey."
"First, you shouldn't let anyone else know that you think he is like Mickey Mouse. Second, he isn't. I don't know what he is, but he's not just a talking mouse. Third, I am a threat. Just because I would never hurt you doesn't mean that I am not perfectly willing to hurt others when necessary. You remember those three idiots back home."
"I thought you said you didn't do that!"
"And I'm not saying I did. Plausible deniability."
Ayako looked at her brother uneasily.
"Don't look at me that way. You know very well that they deserved it, and they survived without a scratch. Besides, I hear that their therapy is going well. Anyways, all things considered, it was a perfectly reasonable request. In any case," he said with a wicked grin, "knowing what is coming is one thing. Being able to do anything about it is another. Come on, let's get to work on the school preparations." Kai got up and went back to his computer, ready to compose a response to Principal Nezu.
"… Okay," Ayako said, not reassured in the least. Rather, she was wondering if it was the right thing, letting him go on like this.
She shook her head and went to preparations, looking at the school shopping list. It didn't matter too much. If anything happened, she would be there to help out.
CREATORS' THOUGHTS 
Tvrkm
Tvrkm Never cross Kai. Will we find out exactly what he did to the three idiots? Not sure yet.
Merry Christmas everyone! Hopefully, I'll get enough time between family stuff to write more chapters.
I very much look forward to Kai's second day of class.