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Something about the air in the class was getting charged and had been for a few days now. No one in the class really had any idea of what it was, but no one denied it was there. It was an agitation that affected all of them. Not even their perpetually irritated homeroom teacher, Aizawa was unaffected, taking a moment longer than usual every morning to observe the class before removing his sleeping bag and curling up. But no one could really identify what the problem was.
So, everyone assumed Katsuki was going to blow up at something.
The final bell rang, and before it finished ringing, Katsuki jumped up, spun around, and slammed his hands down on Izuku’s desk. “Deku! Don't you fucking dare!"
Izuku blinked, looking up from his notebook. “Don’t what?”
Katsuki stuck a finger in Izuku’s face. The class watched Izuku go cross-eyed as Katsuki continued to berate Izuku for something he hadn't done yet. "You've been muttering for a week. I know you're about to do something really fucking stupid and creepy, and I don't-"
Izuku cut Katsuki off by thrusting his notebook into Katsuki's face. The collective gasp across the class was clear in the sudden silence. Such an action was usually the prelude to Katsuki’s countdown to detonation hitting zero prematurely. Kirishima started to move to get between his friend and Izuku but stopped when Katsuki slowly reached up and grabbed the notebook.
He started at it, his lips twisting even more into a snarl. His eyes narrowed as he looked up and glanced about the classroom.
Eventually, his eyes landed on an empty uniform sitting in a seat. The invisible girl let out a squeak as his gaze focused on her and his lips curled in distaste.
"You have to be shitting me," he said, calmly, completely at odds with his body language. It was like watching a video of a car crash, knowing something horrible would happen, but you weren't sure of the exact moment everything was going to off the rails.
"I'm not. That was actually approved." Izuku sighed. It was a sigh of bone-tired weariness that came from someone just completely and totally done with the world. One that usually came from Aizawa when he was debating quitting instead of dealing with the hellions that composed this class.
Katsuki handed over the notebook (gently even!) and brushed his hands against his pants. "Well then, carry the fuck on, I guess."
Seemingly granted permission, Izuku turned around and focused on Hakagure. "Hey! Hakagure?" He asked, brightly, as if the dynamics of the class hadn't just greatly been shifted.
"Uh, yeah? Midoriya?" She squeaked. Her body showed she was still visually tracking Katsuki as he stomped his way out of the room.
"Can I see your blood?"
Katsuki whipped around and shouted, "This is exactly what I was fucking talking about!"
“But Kaachan!” Izuku said, turning toward him, “I need to know-”
“No.” The word instantly silenced Izuku. “You don’t need to know. If she’s going around doing stupid shit, that’s her thing. But don’t be fucking creepy. Why the fuck is this so hard for you?” Katsuki paused and took a deep breath, then turned to Hakagure. “He’s asking if your invisibility extends to your blood. He’s not that crazy mosquito bitch in disguise.”
“Oh,” Izuku muttered as if realizing that, yes, the way he asked that question was confusing, and now he thought about it, it explained the sudden intense scrutiny Aizawa subjected him to, no doubt checking for signs that Izuku was a disguised Toga who had somehow managed to get through the whole class day impersonating him. Apparently finding nothing, and seeing Katsuki vouch for Izuku and explain his reasoning, Aizawa muttered something before crawling back into his sleeping bag and promptly becoming dead to the world once again. He turned back to Hakagure, “Yeah, that… I was thinking about your quirk, and I have questions… a lot of questions…”
“Ummm….” Hakagure began, twisting her whole body so that everyone could see she was looking between Katsuki and Izuku. “I mean…”
Yaoyozoru stepped up. “Is this what I think this is about?” she asked, which caused Izuku to begin nodding enthusiastically. Yaoyozoru smiled and turned toward Hakagure, “Ah, in that case, Hakagure, are you busy right now? I think this is a conversation that you’ll want to have.”
That had just raised more questions in everyone listening, but Hakagure bounced in place, “Well… I was gonna go to the mall with some old friends today, but I guess I can stick around?"
“Great!” Yaoyorozru said, clapping her hands. “In that case, we three can stay after here, we can talk when everyone else leaves.”
At the clear dismissal, everyone began packing their bags. Ilda and Urakaka both looked at Izuku questioningly, but before they could verbalize any of their questions, Katsuki sat back down at his desk with a huff.
“Kacchan?” Izuku began, turning toward his bully/friend/rival/classmate/person with which he shared some kind of deeply complicated and probably unhealthy connection, “Don’t you want to go home?”
Katsuki snarled and turned toward Izuku. “Of course I want to fucking go home, you dumbass.” He crossed his arms and huffed. “But, I know you. You’re too fucking pathetic to yell at someone when you need to.”
Izuku’s friends bristled at that, but before they could rise up in defense of their friend, Izuku beamed. “Great! Oh, that’s a relief. I was a bit worried if I could do that.”
“Yeah, yeah, you owe me for this.”
Hakagure glanced at Yaoyorozru, who was pulling some chairs together. "Perhaps we should sit down before we start talking?"
"Is this gonna take long? Wait, before that, what is going on?" Hakagure half shouted, glancing between the other three students.
"Saving your fucking life," Katsuki ground out. He blinked a few times and turned toward the exit. "Oi, flat face!" The class paused again, looking between Katsuki and Sero. "Remember all the things Racoon Eyes said about the fucking perv?"
"Ashido has been talking about me?" Mineta shouted, jumping up on a desk, "I knew she wouldn't resist my charms for long!"
Sero pushed Mineta off the desk before turning back to Katsuki. "Yeah, what about him?"
Katsuki grinned and chuckled darkly. "Go fucking nuts."
Mineta squeaked as Sero grabbed him. "Hey, Mineta, remember how in the battle trial you left me behind? Well, why don't we get some training in? We can practice more!"
Yaoyorozru got up and closed the door as the class left the room. She sighed and sat down. "Thank you, Bakugou. I was a little worried about how to bring this up with him nearby…"
Hakagure fidgeted. "What are-"
"I'm only going to ask this once," Katsuki interrupted with a growl, "But are you really so fucking dumb as to run around naked as your hero costume?"
Hakagure leaned back away from Katsuki. "It's not like-"
"No," Katsuki once again interrupted, "Yes or no. Is your 'costume'," he said, making air quotes, "the fact that you're invisible and therefore don't wear clothes?"
Hakagure straightened her back. "Yes. I-"
"Good fucking lord! Are you stupid?" Katsuki shouted, jumping up and slamming his hands against the desk. "Don't say anything; you already goddamn did. Fucking hell … Are you looking to get fucking killed?"
Hakagure jumped up as well. "I know it's dangerous! But I need to use my quirk!"
"God fucking damn it, I know our class is filled with idiots, but this really lowers the bar!" Katsuki ranted, pulling at his hair. "I can't believe someone fucking signed off on this."
"Believe me," a voice cut in on them. They all jumped to face the speaker as he growled, "Me neither."
"Aizawa!" Hakagure shouted as she suddenly realized that he was still in the classroom.
Their teacher looked down at the four of them with a pronounced frown. "Hakagure, sign this," he said, handing over a paper. "It's a costume update form. Yes, it's all blank. You will be getting an actual costume soon. In the meantime, I will be having a discussion with Power Loader about how the hell this slipped through."
"Yes sir," Hakagure said sheepishly, signing the paper and handing it back.
Aizawa then handed it to Izuku. "Midoriya, whatever you have planned, fill it out and get that to Power Loader, or whoever his replacement will be, by the end of the day tomorrow."
Yaoyorozru blinked at the exchange before raising an eyebrow. "Replacement?"
"Someone is getting fired." The grim statement hung in the air for a few seconds before Aizawa turned to leave. "I don't know who yet, but I will be making sure of it," he said, before exiting the classroom and slamming the door behind him.
The moment the door closed. Hakagure huffed. "I really don't see the big deal here-"
That was the wrong thing to say. Katsuki whirled on her and invaded her personal space, causing her to squeak as he growled. "You don't see-? You don't-?" Katsuki started and stopped, thrashing with each and every failed sentence. "you idiotic invisible imbecile! You are running around a battlefield naked!"
Yaoyorozru and Izuku both reached up and pulled Katsuki back, but neither of them actually moved to silence him. Hakagure huffed. “Well, I need to use my quirk!”
Izuku finally broke in. “Hakagure, there are ways to use your quirk that aren’t well... Umm…”
“Being a fucking nudist,” Katsuki snapped when Izuku trailed off. “Look, I don’t care if you’re an exhibitionist and-”
“I’m not!” Hakagure screeched, waving her arms in front of her as if to ward off the accusation.
“I said I don’t care!” Katsuki snapped again, “Don’t interrupt me.”
“You’re one to talk…” Hakagure muttered.
“As I was saying, I don’t care if you’re getting your jollies off with you being invisible-”
“Oh my god, no!”
“But this is beyond stupid! This is plus ultra levels of stupid! This is Deku levels of stupid.”
Izuku looked down at his hands while Yaoyorozru huffed. "That's uncalled for!"
Katsuki's eyes snapped to her, "Did he, or did he not, throw away a perfect chance to win at the sports festival and instead chose to individually break each finger and then his arm in order to make his opponent stronger?"
Izuku took a deep breath before fixing Hakagure with a firm look, or what attempted to be a firm look. It didn't quite work when his frown was all wobbly. "Katsuki is right. This is me levels of stupid. Hakagure, I get it. I really do. I couldn't control my quirk, and my only way forward was breaking myself. In some ways, this is similar. You're right, you're invisible, so you can get away with a lot of things that the rest of us couldn't. But, you need protection. And I don’t even mean bulletproof material or whatever else. I mean, you need to not freeze to death during winter, or ruin your ability to walk by stepping on something dangerous in a combat zone, or-"
“Yes, Midoriya, I think she quite understands,” Yaoyorozru interrupted gently, Izuku’s mouth snapping closed with a sheepish look before he could descend into a muttering spree of all the various ways running around naked as a hero was a bad idea.
Hakagure huffed and folded her arms. “Look, I know it’s embarrassing! All right? But I have to use my quirk to-”
Katsuki slammed his hands down, an explosion going off as his sweat ignited. “You goddamn idiot! Mina throws acid!”
The three of them sat there in silence for a moment, first they were processing that Katsuki did actually know Mina’s name.
But then they were trying to figure out why Ashido’s using her quirk was important to this conversation. After several moments of silence, it became clear that Katsuki thought it was obvious and wasn’t going to explain himself. Hakagure let out a breath and rubbed the back of her head and said, "Yeah, that's her quirk. What does that have to do with anything?"
Katsuki leaned over and said very calmly, "What do you think Mina would think if she used an acid with enough power to cut metal and hit you?"
Hakagure hesitated. "It's fine… I know she'd be upset, but since no one can see the scars anyways-"
"Hakagure," Izuku cut in, "Do you have scars from training?"
Hakagure didn't answer.
Katsuki stood up. "Here's what's gonna happen; you're gonna answer every goddamn fucking question this nerd here can think of, then he's going to go home, think of more questions, and you're going to answer them." He grabbed his backpack and swung it over his shoulder. "So, back to the first question. Can we see your blood?"
"So, what's the excuse?" Shouta demanded, standing over Maijima. His eyes itched, but he kept a lid on his emotions. As pissed as he was, there might have been a logical reason why this happened.
Might.
Maijima leaned back in his chair, groaning. "I can't believe we missed this, like… I can see why it happened, but I can't believe no one caught this." He reached over and turned the computer screen to Shouta. "According to her file here, her quirk is a heteromorphic quirk that only requires protections on her hands and feet which also need to be removed quickly. We've had a few people come through with complete body mutations before with similar phrasing. Iron Sides being a notable example."
Shouta huffed. "Don't recognize that name."
"His quirk was called Iron Golem. Literally, he was a giant made of iron. Also had a bit of a hate-hate relationship with clothes, since fabric would bunch up on his joints and cause problems."
"So you didn't notice the girl was running around naked?"
Maijima gave a pointed look at Shouta, "And neither did you. At least I have the excuse that I don't see any of your students, just what their file says." Maijima sighed and shook his head. "It doesn't help that technically, I don't even approve of the designs. The first costumes are subcontracted out. So the final designer was even more removed from knowing why this costume was requisitioned."
Maijima reached over and grabbed the phone. "I'm going to call Nedzu and tell him about this. In the future, we need to do better. This happened because we were just stamping forms and we-"
The door to the labs opened with a loud bang, Shouta assumed it was another accident from the support department students, but Maijima jumped up and walked around him, obviously confused.
That meant the two of them had just enough time to walk out of Maijima's office and see Midoriya standing in the doorway as his eyes landed on Mei.
"It has been stated," Izuku began, his voice echoing across the lab that went very still when he entered. Shouta felt a headache growing with every uttered word as every student listened to him. "That that the human body is chemically equivalent to a mix of water, carbon, ammonia, lime, phosphorus, salt, saltpeter, sulfur, fluorine, iron, silicon and trace amounts of fifteen other elements."
The room was quiet as they waited for him to continue that thought. When he didn't, Hatsume took several leaps towards him, her eyes alight with what Shouta would call madness. "And?" She prompted.
Izuku took a deep breath and said, "What can you do if you could replicate Toru Hakagure's blood?"
The whispered, "Fucking hell," for once, didn't come from Shouta but instead from the teacher of the support course next to him.
"This sounds like a you problem…" Shouta said, leaving the room. "I will go inform Nedzu about the costume problem."
"Aizawa, I swear to Nedzu, you better take your problem child with you!"
It was a week later when the fallout happened. No one had really forgotten what had occurred when Izuku turned around and asked one of the creepiest questions he had ever uttered.
In recent memory at least, Katsuki still remembers the look an old classmate had when Izuku asked what would happen if the eye stalks he had got cut in hero work. (The answer was exactly what you'd expect, and that kid never used his quirk in class again.)
But Aizawa told them they were doing class training again and told them to grab their uniforms.
Hakagure's case had always been light. Two gloves and two shoes were nothing compared to just one of Katsuki's gauntlets let alone anyone else's costume.
So when she let out a yelp and the case fell onto the ground with a thud, everyone turned and looked.
"You alright?" Ashido called out to her friend.
"I'm okay! But do I have the wrong case? This is so heavy!"
Izuku jumped and tried to peer around the growing crowd of concerned classmates. "Oh, Mei must have finished! That's great!"
"Finished what?" Hakagure asked, opening the case. The moment she did so, she let out a squeak as a liquid began to spray, covering the inside of the case.
And also revealing the shape of something invisible.
"Oh! So that's how she decided to do that! I was wondering what she'd do. We talked about using some sort of dust, but that would be hard to clean off. And Power loader's suggestion of using electricity to polarize it so it'd be dark when-"
"Nerd," Katsuki cut in.
"Yes, Kaachan?"
"Shut the fuck up."
"Okay!"
Hakagure reached in and lifted one of the items in her costume case out of it. If it weren't for the water dripping from it, it'd be completely invisible.
"What is this?" Hakagure asked.
Mineta gave Hakagure a funny look. "A costume, duh? Isn't this your … wait…" his eyes grew alight with a fire that was never seen in him during heroics, "Were you-"
"It's a DNA suit!" Izuku shouted as Katsuki grabbed Mineta and dragged him away. "Sort of! I did a bit more research, and traditional DNA suits are normal fabric but treated chemically so your emitter or transformation quirk recognized the suit as part of your body and or quirk."
Everyone turned to focus on Izuku. Normally such attention would make Izuku grow anxious and panicky, however, he was on a roll and beginning another mutter storm, and this time people were interested.
"This technically still qualifies as a DNA suit, but it's a bit more involved. Everything in it is made from you in some way, since it seems your quirk alters everything about you down to even the base building blocks that make you. For example, there is a compound in your saliva that quickly breaks down what you're eating so we can't see it."
Jirou leaned over the desk and poked the suit with a finger. "So what is this then?"
Izuku smiled brightly. "Oh! That's easy! It's mostly Hakagure's hair. See, DNA costumes are expensive, but it's not really the chemicals that make them expensive. Rather it’s the fact that the hardware to produce them is unbelievably expensive, let alone the maintenance cost. That doesn't sound like much of a distinction but since U.A. has a lot of students who need these types of costumes, they don’t just have one of the DNA replicators, but four! So, they were able to replicate Hakagure's hair to produce most of the fabric for this costume."
"That's great and all, but… what is this?" Hakagure asked, reaching into the suitcase and once again grabbing something invisible. She tapped it against the desk, and a clang rang out. "That doesn't sound like hair to me."
"Oh, no, that's steel. Mei was able to make an invisible metal from the iron in your… well… in your blood."
Jirou leaned back and looked at Izuku, "You had them make metal gauntlets… out of blood?"
Izuku rubbed the back of his head. "Well… yes… I know it's a little weird but-"
"No," Jirou interrupted, "it's metal as fuck."
"But…" Everyone turned as Yaoyorozru interrupted. "Steel is iron mixed with carbon… blood doesn't have carbon in it."
Izuku shook his head. "no… but human bones do."
Jirou took a deep breath. "You're telling me… the support department has the ability to create massive amounts of human blood, bones, and hair, and you used those to have Hatsume forge a costume for Hakagure using all of that?"
Izuku blushed as Katsuki scoffed. "I told you all he was creepy."
Jirou turned toward Katsuki. "Creepy? This is the coolest shit I've heard of in my entire life."
With that, her jacks snaked out and wrapped around Izuku’s upper arm, yanking the boy towards her.
“Alright, everyone, listen up!” She shouted to the whole class. When she had their attention, not least of which included the eyes of a stammering and slightly scared Izuku, she flung an arm around his shoulder.
“Dibs.”
“D-dibs on what, Jirou?” Izuku asked, nervously, tuning out the delighted squealing coming from Mina as something he really didn’t want to think about the implications of.
His near-nervous breakdown decidedly did not improve when the rocker girl turned a smirk on him. “I call dibs on being your next costume redesign, broccoli boy. If it’s even half as metal as human leather, or steel made from my own goddamn blood, I’ll call it a win. Been wanting to update for a while anyway. What do you say?”