(Narrator's P.O.V)
When All Might noticed Y/n laughing oddly, as fast as she started, she fell asleep.
"You reached your limits again, haven't you?" He mumbled mainly to himself.
"You Bastards!" He sat up just a bit, watching Tomura throw a fit as he realized he has lost. "You just got lucky that you had 16-L.R on your side, because if you didn't, my Nomu would have killed you by now!! All of you!"
"What is 16-L.R?" All Might growled, standing up.
The villain scoffed. "That girl you all call Y/n L/n. Don't tell me you didn't know that? You are so pathetic. It doesn't matter if you knew or not anyways. She'll kill you in no time if you keep her around. That's what she was made for."
"I don't know why your still talking!" Bakugo yelled, running at Tomura. Izuku was at his back trying to stop him. "Ka-chan! Stop!"
All Might went to get up to stop them both, but they were both too close to be saved when they tried to stop. Tomura outstretched his hands towards both of their faces, about to disintegrate them both. Then a bullet shot him back away from the two, and then was hit a few more times, injuring him until Kurogiri jumps over to protect him and they both escape together.
The pro heros were finally here. After everything calmed down, the extra villains the kids fought with were apprehended and Detective Tsukauchi and the police debrief the students and confirm the status of everyone involved. He confirms to Izuku and the others that Aizawa and Thirteen will all be okay.
Before the detective could get to y/n, who still remained unconscious, a police officer sprinted up to him with three other policemen, and informed him of the fowl massacre at the back of the joint beyond the tree line. He had asked the students if any of them were with Y/n during their time in the different zones, but they all said no.
He proceeded to take him and the other heros, including All Might, to the back to see the massacre for themselves. When confirmed, they stared in horror at the carnage brought by Y/n. With her absence in the beginning of them event and the amount of blood on her, it was obvious she was the one to commit those murders.
Midnight shuddered at the foul stench of death as they were forced to walk through it all and help count the bodies that weren't smashed to mush. "How-how could she do all this?" She asked herself as tears came to her eyes, remembering the times she was with her, her smiling face, and happy attitude. "This couldn't have been her. She couldn't have done this- she's too sweet! Why?? She wouldn't do this, so why!?" She cried stopping in her tracks and covered her face. The hero's body shook as the dead laid circled around her. Present Mic came up and consoled her.
"I know, I don't want to believe she would do this either," his voice was soft and heavy, unlike any other time, "but we have to face the facts. She did something like this before, so she could do it again. We just have to keep a close eye on her."
"I don't think that'll be enough. The Chief of Police just got here, and he's not happy with the photos we just sent him. He has Y/n secured in her security transport, and she's just now waking up. Let's go back." The detective sighed and led the heros back. When they saw Y/n, she was not in the best state of mind.
"Haha! Come on chief! I missed you! It's been-I don't know how long since I've seen you~! Let me out of these restraints and let me show you just how much I've missed you~!!" She mewled and chuckled, shaking and jolting in her constraints of a bulky dolly with many security systems tightening around her with every move she made, though it seemed like she was enjoying her painful self torture. The chief growled and shook his head.
"So you went and created a massacre once more huh, L/n?"
"I call it self-defense!!" The girl hollered with a giggle at the end.
"What the hell has gotten into you girl?"
"U-um excuse me s-sir!" The green haired student called out, nearly stumbling down the last steps.
"What are you doing down here boy? You were told to stay up there with the other students."
An officer came down after him huffing and puffing in exhaustion. "I-I'm s-sorry sir! H-he slipped p-past me!" He panted.
"Sir! I can explain! I found out, Y/n is acting like this because she has reached the limit of her quirk. That's probably what happened to her before she found us and saved me and the others from Tomura. The same thing happened when she went too far during her practice battle with the teachers! Her down side to her quirk is her losing her sanity!" Midoriya explained in a rush. The chief stopped for a moment to think and looked back to the girl huffing, not struggling as much in her restraints out of tiredness.
"What else did you get to know about her during her time here?" He looked back to the nervous boy.
"W-well, she isn't normally like this. But when she is, she gets her sanity back pretty quickly when she sleeps. She's normally a sweet, kind, smart, considerate, and the most heroic out of our class from what she did today."
"What did she do?"
"She saved me and two others from the Nomu, but it smashed her head into the ground over there, and nearly died. Though she was about to die, using the little bit of energy she had, she still protected us, even though she couldn't move. She was even the one who helped All Might defeat the Nomu in the end! So please, don't arrest her! She didn't do anything wrong!"
Y/n could do nothing but watch the transition go on between the chief and Midoriya. The longer she stared at the young hero, the more her sanity was coming back to her than usual. Though she wasn't tuned into the actual conversation.
"This is good new information boy, but I'm afraid that doesn't change the fact that she killed over 30 villains today."
The boy seemed to stop breathing and looked him dead in the eyes. "What?"
"Yes. From the stories you and the others gave to the detective, and now your information just now, I understand. The warp villain Kurogiri transported you all to the different zones, but with Tamura's strange infatuation with L/n, he had her transported far away from everyone to be dealt with at the far back of the joint, and during the fight, she went passed her limit and fell into insanity, and proceeded to start a massacre. More or less in self defense, yours and everyone else's comments towards her, and her plea of insanity-or just her proof of it, may work in her favor in court and keep her from being sent back to the same prison cell she had before." A moment of silence went on after that. Midoriya stood in shock and confusion until he looked to the side, and made eye contact with Y/n. Other than all the blood on her, her face was calm and normal like any other day. She was just staring at him as if in wonder.
'How? How does someone like her kill people and still manage to look as calm as she does?' He thinks in fear.
"Y-you're lying...sh-she couldn't do something like t-that..." He mumbles. The chief shakes his head.
"Unfortunately, I'm not, look," He shows him the pictures he was sent on his phone. The sight of blood and gore of the dead in front of the facilities wall nearly makes the boy puke, and turns away from the sight to gag, holding back what wants to come up from his stomach. "I'm sorry, but this is just one of the worst of what you will see when you become a pro hero. Your teachers, when they are not training you, have to risk their lives to fight villains with power like L/n's, to prevent events like these. Granted these were just villains, but murder is still murder, no matter how you look at it. Keep that in mind." He puts his phone away and looks to the police officers. "Alright, round up the surviving villains and L/n. We're leaving." As they put the criminals into multiple carriers, the teachers and students walked outside of the joint and watched. Y/n was the last one to be put in a high level prison transporter. Her head was hung low, letting her face be masked by her hair. Though her quirk was canceled by the restraints, everyone felt the air somehow feeling heavy and cold.
"I don't understand. Where is All Might? What happened to L/n? Did she do something wrong? Is she going to be okay?" Uraraka asked towards her teachers in concern, with the other girls behind her, watching Y/n's prison transport ride off with her.
Midnight placed a hand on the girl's head and sighed. "I'll explain when we all get back to class." She watched solemnly as the police officers closed off the joint and stood guard. "Alright everyone, you're all going to Recovery Girl to get checked up on just in case, then you will all get dressed back into your uniforms and get back to class, understood?"
"Yes ma'am." The class all said, and walked back to the bus. The ride back was uncomfortably silent for everyone. Uraraka couldn't stop thinking what will happen to Y/n. During that time, she glanced up to Izuku, who was slouched down in his seat with his head hung low and elbows on his knees, unable to see his eyes. She worried for him and everyone else who were thrown into separate zones, and hated that she couldn't help them through the whole ordeal they were forced to go through.
The rest of the school day went just as was planned and in the last 20 minutes of class left they were all in class, quietly listening to the events of what happened to Y/n, and what will happen from then on.