Katsuki scowled as he stalked through the halls tuning out the sounds of the extras as he's done since he was five. He paused as his ears picked up on some extra saying he trained his quirk over the break and that he will be a hero in no time, he focused on his sound and found it pathetic and so he glared at the kid for insinuating that he was on his level. The kid flinched and so Katsuki continued walking, the nerve of this extra to think that he was Hero material, only HE had what it takes to be a Hero from this dump.

His scowl deepened as he made his way to the classroom meaning he will hear Deku again, the all-consuming silence in an ocean of noise. He hated Deku because he Scared infuriated him, his gaze that felt like he was picking you apart piece by piece, and his casual mutterings of strengths and weaknesses and everything that makes up a person as if he knows you better than you know yourself, it Terrified enraged him. sparks crackled in his palms at the thought of Deku, the freak that had no sound when everyone else did even that old quirkless lady at his favorite Chinese restaurant has a sound, as small and muted as it was, a small crackling ember compared to his explosive symphony.

He paused when he neared the door a new sound graced his ears, it was rather complex but simple at the same time the easiest way he could describe it was a relaxing camp scene a crackling fire, a gentle breeze, the calm bubbling of a creek, the steady thrum of the earth, and something that tied them together, it was one of those weird esoteric sounds. He stood there reveling in the relaxing song for a moment and was soon snapped out of it by the bell. Realizing he will be late if he stands about any longer, he heads into the classroom ears twitching to locate the song coming from . . . DEKU.

He stares at Deku if confusion, frustration, and relief. He huffed and stomped towards the nerd and tapped him on the shoulder to pull him from his damn notebook and said quietly, "You and me, the roof during lunch."

Deku turned to look at him surprised and Katsuki flinched ever so slightly as he felt as if he was being dissected, it passed as fast as it came, and then the nerd nodded. Katsuki took his seat and for the duration of the class, he focused on Deku's sound, and as much as he hated Deku he enjoyed his song it was relaxing in comparison to the extras that made a sea of white noise. He eventually came to the conclusion that Deku had a quirk now, but he couldn't pinpoint what exactly it was everyone's sound correlated to their quirks in some way or fashion but his had too many components to it. He mulled it over until the bell for lunch sounded, he shot a look to Deku who nodded and left his seat grabbing his bento and headed to the roof, Katsuki followed a moment later.

He opened the door to find Deku standing nervously on the roof, Katsuki took a moment to observe him finding him different than a month ago more confident in himself, better posture, and ready to move at a moment's notice, 'So, Auntie Inko has been training the nerd like the hag said then.' He walked up to Deku and watched as he squirmed a bit and said, "You have a quirk."

He let out a strangled, "How did you know," in surprise.

Katsuki huffed and said, "It's not important, so what is it."

Deku then began to mumble out about his quirk and Katsuki nodded along but scowled as the explanation didn't seem quite right compared to the song he hears; nerd probably doesn't know what all he can do then. Deku then pulled out a pencil took a breath and then Katsuki's ears twitched as Deku's song raised in volume. He watched as green circuit colored lines spread the surface of the pencil, the nerd then handed it to him and asked him to blow it up to which he obliged and flexed his quirk. He looked at the still intact if slightly charred pencil with a raised eyebrow then released a stronger explosion that shattered it, 'That's the kind of power I use to shatter concrete.' He thought in surprise.

Katsuki muttered, "Not bad Deku."

The nerd then stood there gaping at him like a fish, as if he was incapable of giving compliments or something.

The two of them stood there for a few awkward minutes and it was then that Katsuki realized that this is the most relaxed he's been in Deku's presence since before his quirk came in. they stood there until the roar of Deku's stomach broke the silence, the nerd looked bashful and then pulled out his lunch. Katsuki and Deku sat there in silence enjoying their lunches and made very awkward small talk.

"You have curry today too," Katsuki asked.

"Ah, yeah I helped mom cook it yesterday and we made too much," Deku replied.

"Same, spiciest batch we made yet," Katsuki said gesturing to the very red curry.

"What kind is it," Deku asked drooling slightly which reminded Katsuki that the nerd likes spicy stuff too.

"Mapo Tofu, want some," He said as he watched the nerd twitch slightly and then proceed to nod happily.

"Sure, you can have some of mine if you want," The nerd replied with a smile.

The bell rang some time afterward and they packed up their lunches and made way back to class. The two of them not sure what to do about the awkward tension that now rested between them.

Katsuki spent the rest of the day thinking about Deku not sure what to feel about him anymore, his Fear of the Unnatural Hatred? Of him faded. Katsuki also realized this is the most comfortable he's ever felt at school, probably since the was replaced with a calming song. He didn't notice that the extras looked at him in confusion since he was lost in his thoughts.

Izuku wasn't sure how his first day back at school would be like sure the usual silent jeers were there but he had long since learned to ignore them but what he was really worried about is Kacchan. He truly worried about Kacchan he was one of the few he could consider a friend but even with him occasionally literally hunting him down, Izuku could never forget the fear he saw in Kacchan's eyes whenever he looked at him. He buried himself in his hero notes to distract him from that line of thought and put his newfound knowledge to use. So far it allowed him to start to piece together how some quirks function in detail, he itched to reach for Lord El Melloi's book for clarification on something, but he left it at home for safety. He didn't know how much time had passed until someone tapped him on the shoulder and said quietly, "You and me, the roof during lunch," Recognizing the voice he turned to look at Kacchan in surprise. He looked at him and noticed his ears twitch slightly, 'his nervous tick', and nodded in agreement.

Izuku was internally freaking out for the first half of the day with his thoughts running rampant about why Kacchan would want to speak to him this continued until the bell for lunch rang, he shot a look towards Kacchan who glared at him in a questioning way too which he nodded nervously.

Izuku stood on the roof of the school nervously he honestly liked to eat his lunch on the roof not many people went there, and the winds always relaxed him but today it did little to calm his frayed nerves. His thoughts went to the reason Kacchan told him to meet him on the roof. One such train of thought ended on the conclusion that he wanted a fight and even with his mom's summer boot camp Izuku didn't like his chances. Another more rational part of him concluded that Kacchan actually wanted to talk but that got squashed slightly under his anxiety.

His thoughts came to an abrupt stop by the sound of the door being opened and then proceeded to go back into overdrive when Kacchan walked up to him and just stared at him.

If he thought his mind was erratic before with Kacchan's next few words it spiraled and so his mouth worked on autopilot and condensed all his rampant thoughts into a few words, "How did you know."

A part of him got irritated at the blonde's statement of it not mattering how he knew because the only people who knew were his mom, his grandparents, and his doctor. Izuku knew for certain that the only way he would know is from aunt Mitsuki, but his mom hasn't talked to her recently. He went ahead and explained his 'quirk' to Kacchan, and the more analytical portion of his mind began to take note of his reactions such as his confused grimace and the twitching of his ears as if they are focusing on something.

Izuku finished his explanation by taking out a pencil and applying reinforcement to it and asked Kacchan to blow it up to show its newfound durability what he didn't expect was the compliment, Kacchan hardly ever complimented anybody let alone him so he stood there gaping at him for a moment.

The rest of his day was odd given the fact he sat and ate lunch with Kacchan, and he didn't get exploded. He even had a rather amicable conversation with him, and he got to eat auntie Mitsuki's Mapo Tofu. He still didn't know why he had a brief moment of terror when Kacchan said Mapo Tofu, he loves spicy food it's one of the things he inherited from his dad.

Izuku had spent the rest of the day picking apart the mystery that is Kacchan. He was walking home when the pieces slowly came together from his day of observation. One of the easiest observations was that Kacchan wasn't as tense as he usually was, he didn't snap or glare at anybody at all today apart from him a few times and even then, they weren't as heated as usual. The other would be his eyes when he looked at him, he didn't see any fear just confusion and a hint of appreciation? Thirdly were his ears, he picked up their twitching a lot today and he was beginning to think they were more than a nervous habit. He arrived home greeted his mother and headed to his room and continued his train of thought. He plucked an older version of his hero notes from his bookshelf and leafed through it finding his entry on Kacchan.

'Quirk' No

'Physical ability' No

'Adaptations?' Yes

'Eyes are adapted to handle bright sudden flashes and recover faster than average.' No

'Enhanced hearing?' Yes

'Adapted to handle the sound of his explosions and other loud noises. Complained about too much noise when it isn't that loud, High sensitivity? Talked about weird noises like fire or running water?'

Izuku set down the journal and began to remember it was around the time Kacchan's quirk manifested is when he began to complain about people making weird noises and when he started avoiding him with fear in his eyes. Those times were always a bit hard to remember as it was after his diagnosis and everybody started treating him differently, well apart from his mom.

Izuku also needed to find out how Kacchan knew he had a quirk as it wasn't obvious at all. At that thought something clicked 'Hearing, Sense, detect.'

Izuku reached for one of his magecraft books and flipped to the chapter detailing how one can detect mystical effects. He knew he could detect magical effects through sight, and it allowed him to see 'more' than most people and that it only got stronger after he opened his circuits so who's to say it can't happen to people when their quirks come in. He reread the section on the senses about how it can manifest in people and how it varies in strength from barely noticeable to scarily potent.

'The detection of magical effects is usually tied to one's senses not directly but as a form of synaesthesia and can vary in power from as simple as noticing an odd scent in the air to being able to see the immaterial.

This ability can be cultivated or artificially created but there are rare few born with the natural talent for detecting magical effects and as such can display special abilities.

The more common variant of this belongs to sight or rather mystic eyes if the effect is potent enough. However not all mystic eyes fall under detection and their effects can vary.

The cases of other senses are rare and far between and as such are not given a general classification. There however are notable examples such as Wolfgang Amadeus Mozart and his exceptional hearing that was rumored to allow him to hear and distinguish any and all sounds, even that of the soul. It is what allowed his musical magecraft even greater heights.'

Izuku reread that last bit, 'even the soul,' he flipped through his notes on Kacchan again and checked about the weird sounds he complained about.

Crackling of embers, the bubbling of water, whispering winds, rumbles of the earth, and nothing from me.

Could Kacchan hear people's affinities? If so that explains a lot, but why did he hear nothing from him, was it because he was quirkless, but he heard him today that's how he figured out he had a 'quirk'.

Izuku contemplated his findings and decided to wait and see if Kacchan showed any other signs. He also entertained the idea of confronting him about it but didn't want to get exploded, maybe one day.

The next few weeks of school were odd for everybody not just Izuku given that Kacchan's outburst were now far and in-between. Although after a week he returned to his usual crass and blunt attitude he was mostly relaxed and amicable, well as much as he can be but a definite improvement. He also didn't get chased anymore, now Kacchan just appeared in his hiding spots with a smug grin. Izuku didn't know if he preferred getting hunted down like an animal if it meant he could enjoy his lunches in peace again but the occasional lunch with Kacchan wasn't too bad given that he shared his delicious spicy food even if the conversations were just as awkward as the first time. Now he could reasonably say Kacchan was his friend again but five years of bullying doesn't just go away in one awkward meal so the tension was still there and remained that way for the foreseeable future given that apologizing was not a thing that Kacchan did easily.

OMAKE: The Dreaded Shinai

Katsuki sat at the dinner table enjoying his dinner when the hag asked about his day. He paused and mulled it over for a bit and said, "It wasn't that bad, and the nerd finally got his quirk." He then resumed eating ignoring the sputtering of his parents.

"Little Izu-Kun did, how did that happen," Asked the hag.

"He said something about a shinai being made with his ancestor's quirk doing something to him," he said as he grabbed a drink from the kitchen. He believed the nerd about that; He knows enough about quirk theory sitting next to the nerd to understand his ramblings. He turned back to look at the ashen face of his mother and the worried grimace of his father and scowled in confusion.

"What," he said in frustration.

His mother started crying about how 'little Izu-Kun is going to be a delinquent and about how he's going to become a beast.'

Katsuki not wanting anything to do with the situation quickly gathered up his plate and dashed to the kitchen to wash up his things and made a hasty retreat to his room.

A few minutes later he hears a knock on his door to which he looked at cautiously before his father spoke up, "It's me Katsuki, can you let me in."

He grumbled and opened the door for his dad.

"So, do you want to what happened earlier?"

"No."

"Really, not even a little."

"No."

"Are you sure?"

Katsuki glared in a random direction for a minute before muttering, "Ok."

His dad smiled and told him about how his mom and Deku's mom grew up in the same town and that Deku's mom was a bit of a 'troublemaker' when she was younger and that she liked to fight and how she used a shinai as her main weapon. He told him a few stories about auntie Inko, and he didn't think he would look at her that same way again. Katsuki knew she was strong given that she had a song and not a sound like other extras, but he didn't think she was 'The Queen' of her town. The thought of the nerd training with her and becoming strong didn't sound too bad, a proper rival someone to push him to become better and stronger than ever. After an hour his father left and Katsuki couldn't stop the savage grin from forming on his face he had a Rival.

A.N. I know most people don't like Bakugou, but I wanted to have an early 'redemption' arc and give a somewhat believable reason to his disdain for Izuku, so I framed it as fear and Bakugou is one to kick his fears in the teeth. For those wondering why, he's a kid and he relies on his hearing a lot to find and categorize people so when everyone makes a sound except Izuku he singles him out. As for the reason why Izuku had no sound its because Izuku before circuit activation completely blended in with the ambient sound as his alignment made him balanced instead of leaning towards any other element like most people and after circuit activation his sound became more pronounced to the point Katsuki can hear it.