A/N: Oh look at that I had another idea for a fic.

Honestly I should probably have held off on this until I had more figured out, haven't really sorted out many enemy Stand Users, but eh, whenever did that stop me?

ゴゴゴゴゴ

For as long as he could remember, Midoriya Izuku wanted to be a hero. This was a common dream among children in his hero society, more popular even than being an astronaut or a movie star! It all started with a video of his childhood idol, All Might, saving people from disaster with a smile on his face, and was only brightened by the fact that the best friend of his childhood, Bakugou Katsuki, was also enamored by All Might! When the boy, who Izuku called Kacchan, gained a dazzling explosive Quirk at the age of four, it only made Izuku excited for when the day he would finally learn what his own Quirk was.

That is, until one dreadful doctor visit.

"As you can see, he has an extra joint in his pinky toe," the old doctor said lazily as he pointed to the x-ray of the boy's foot.

"What does that have to do with this?" his mother asked.

"Well, Quirks are a sort of... next evolution of the human body. This toe joint is completely unnecessary, so those who do have the evolution of Quirks don't have it. Your son has the toe joint, so unfortunately, he doesn't have a Quirk."

"But... but my Izuku dreams of becoming a hero!" his mother said, tears starting to form in her eyes.

"I'm afraid that there's nothing that can be done about it," the man said, completely nonchalant even as he ground Izuku's dream to dust.

The revelation crushed both Midoriyas. That night, young Izuku watched the video of All Might that had inspired him to be a hero over and over again, too numb to even cry. His mother, however, cried more than enough tears for the both of them, profusely apologizing to her son for how unattainable his dreams seemed to her.

Despite his lack of a Quirk, despite how impossible even his own mother saw his dream, Izuku eventually pushed on. He began to keep journals, analyzing the strengths of any Quirk he could get information on... and picking apart their weaknesses. His classmates would jeer him, calling him a creepy Quirkless kid or a useless Deku, from a mistake Katsuki had made when reading his name when they were first learning how. They would never willingly include him in any group activities, citing his lack of a Quirk as something that would make him a terrible playmate even though they weren't allowed to use their Quirks either.

The thing that had perhaps hurt the most, however, was how Katsuki joined in with the bullying. The two boys had been best friends, perhaps even brothers, since infancy, their mothers having been best friends in school. But after Katsuki got his Quirk, all their fellow classmates and even teachers gushed about his Quirk and how great it made him. Katsuki, being only four years old at the time, believed them without question. And when Izuku was told he was Quirkless months later, he continued to side with them when even the teachers called Izuku weak and worthless. He would yell at the "worthless Deku" for still trying to be a hero even without a Quirk, using his explosions to intimidate him when he did anything heroic and seeing any attempts to still be friendly to him as condescending.

And yet Izuku still pushed on. He endured the jeers of classmates that looked down on him for his lack of power, pushed past the loss of his most cherished friendship, ignored the teachers who told him he'd never amount to anything. However, Izuku did not come through this ordeal unaffected. Some nights he would cry himself to sleep from the bullying. The once-cheerful child's optimism dulled over the years as his classmates insulted him and his teachers called his dream impossible. His mother worried about him, but he would never reveal to her just how bad it was, thinking that it would prove the bullies right and he would be weak. In short, his life was miserable.

But that all changed one fateful day, roughly five years after the doctor told him he was Quirkless. It was a day seemingly like any other for the nine-year-old Izuku. He got up, went to school, and his classmates insulted him for his Quirklessness. However, while he was doing schoolwork in his last class of the day, Izuku jumped in his seat as he suddenly felt a sharp pain in his chest! It was as if someone had shot him with an invisible arrow. Unbeknownst to him, this event coincided with a man he had never met in his life driving an actual arrow into his own chest kilometers away. Izuku clutched his chest, looking down to see an emerald flame sprouting from his phantom wound with a burning sensation. His eyes rolled up in his head as the illusory fire spread across his body, the heat and pain causing him to lose consciousness!

Izuku's classmates scoffed and ignored him as he went limp and fell to the ground, assuming it was some strange ploy for attention. Of course, they couldn't see the strange green fire that his body had somehow started to produce. "Midoriya, please return to your seat," the teacher ordered. Being unconscious, Izuku found it rather hard to follow his orders. "Midoriya, your seat!" the teacher scolded. Izuku stubbornly refused to regain consciousness. "I swear, this kid..." the teacher grumbled to himself, storming over to the child. "Alright, get-" he started to say, reaching a hand to Izuku's arm in an attempt to drag him to his feet.

"AH!" the teacher shouted before his hand could even make contact, jumping back as if he'd been burned. He shook out his now-red hand, feeling like he'd just touched a red-hot stovetop. "What the hell..." All eyes were on Izuku and the teacher. The man frowned, then took a paper from Izuku's desk. He held a corner up to Izuku's face. The paper slowly blackened, then set on fire! "Shit!" the man shouted, quickly waving the paper off to extinguish it. The class looked on, stunned. They had clearly seen the paper light on fire seemingly just from touching Izuku, and now the room smelled of the smoke that the paper gave off when the fire went out. Could the Quirkless Deku have spontaneously developed some sort of heat power?

Whatever had happened, it was clear that it was having a detrimental effect on the boy's health. It didn't look like he was being burned like the things that tried to touch him, but he was still unconscious. His breath was labored, and he sweated as if he had a high fever. The teacher quickly sent Izuku to the school nurse's office. He'd needed to improvise a makeshift stretcher from a fireproof blanket that his classroom had as a safety precaution due to Katsuki's Quirk being a potential fire hazard. Then he had Katsuki help transfer Izuku onto the stretcher due to the fact that he was the only one there that could touch him for even a moment thanks to the heat resistance his Quirk gave him. Katsuki had balked at the instructions, but the teacher reminded him that he'd have to do things like that if he wanted to be a hero.

The nurse gave Izuku some cool water and ice packs, but they quickly heated up under Izuku's anomalous temperature. The nurse's office of an admittedly subpar elementary school simply was not equipped to deal with this mysterious illness. They quickly called for an ambulance, as well as a local fire rescue hero with a heat-resistance Quirk to help move and treat the boy who burned whatever he touched. The ambulance took Izuku to a specialist hospital immediately.

ゴゴゴゴゴ

Bakkuta Infirmary, a hospital founded by the medical and Quirk research group called the Speedwagon Foundation known for dealing with unknowns and special cases. This mostly means Quirk accidents and mishaps, though sometimes more obscure injuries and maladies find their way within its halls. Based in Musutafu, it often sees cases from the relatively close Yuuei High School that their school nurse, Recovery Girl, can't deal with herself. However, it is not uncommon that patients come in from further away, as the hospital is well-known and quite reputable.

Midoriya Inko fretted as she paced around the hospital hallway, on the verge of tears. Her baby boy passed out in the middle of class! The doctors couldn't tell her what was going on, and they wouldn't even let her see him yet! They were still running tests on him! As she paced a track in the floor, she heard the sound of a pair of heels frantically clacking against the ground. She turned around just in time for a rather short blonde woman in a suit to run directly into her.

"Sorry, sorry!" the woman apologized, bowing. She looked rather frazzled, and it seemed that in her stress she'd activated her Quirk as her hand seemed to have fused partially into the handle of her purse. "Sorry, I... should've looked where I was going."

"Oh, no, you're fine!" Inko said. "Really, I should be apologizing for blocking the hallway!"

"Oh, you're fine!" the woman assured her, waving her hands. Her purse was still stuck to her hand, causing it to flail and nearly hit Inko in the face. "Ack, sorry." Finally noticing her purse, she concentrated for a moment, separating it from her body. "It's... It's Bakkuta, I'm sure there's something you're worried about."

Inko nodded. "Yes, there is... But I'm sure you can say the same thing?"

The shorter woman sniffed, then started bawling. "M-my s-s-son!" she managed to cry out, tears streaming down her face.

Inko, ever a sympathetic crier, found this to be what burst the dam of her fountainous tears. "M-my son too!" she bawled.

"Neito!" the woman, possibly mother of a boy named Neito, shouted, grabbing Inko in a hug.

"Izukuuuu!" Inko responded tearily, returning the hug hard enough to lift the woman off her feet.

The two worried mothers cried into each other's shoulders for quite a while, stopping only when interrupted by a man awkwardly clearing his throat. Both women jumped, turning to see a tall doctor in a labcoat, holding a clipboard. "Sorry for interrupting," the man said. "You are Midoriya-san and Monoma-san, correct?"

"Yes, I'm Midoriya Inko," Inko said, wiping the tears off her face.

"Ah, Monoma Tomiko," the other woman said, brushing off her suit.

"I've got news for the both of you," the doctor said.

"Good news?" Monoma-san asked hopefully.

The doctor frowned, thinking. "At least... definitely not bad news? Now, we understand that medical information can be sensitive, so if you'd prefer me to take the two of you apart so you can have privacy..."

Inko glanced at Monoma-san. "I think I'll be fine."

Monoma-san nodded. "I don't have any problem with that."

"Right, right. Both of your sons seem to be doing better than they were when their conditions developed. Their symptoms seem to be... waxing and waning in severity, for lack of a better term. Again, it's never gotten worse than they were at their onset, but at times they look almost like they're just sleeping while other times it's still clear that something is amiss."

"That... sounds good?" Monoma-san said, slightly unsure.

The doctor nodded. "It's promising, at least. The weirdest bit is that their symptoms seem to be in sync, aside from Midoriya-kun's temperature. We've run tests, they're not contagious, infected with anything, suffering from any sort of poison, injured, or have any sort of damage to their organs. It's... a bit strange to say, but if they weren't currently unconscious with on-and-off fevers I'd say they were both the picture of health."

"Is there anything you can do?" Inko asked.

"We have a few ideas we can try, but..." He shook his head. "I apologize, but if this is what we think it is, there might not be anything to do aside from let them ride it out. We do have one hope, though, that it's something related to their Quirks. Our tests have detected certain similar elements in their Quirk Factors that could suggest... something, either an outside cause that targeted them for that or a random development that coincidentally happened at similar times and had similar side effects. That last one isn't exactly likely, unfortunately, but we do have a way to rule it out without any damage to them so we might as well try."

Inko blinked. "But... Izuku is Quirkless?"

The doctor frowned, clearing his throat. "About that... Okay, this bit might be really sensitive, so if the two of you don't mind I'd like to speak to Midoriya-san one-on-one for it."

Monoma-san nodded. "Of course, of course." She frowned. "Ah, where is the nearest bathroom, again?"

The doctor pointed down the hall. "That way, take a right and it should be on your left."

"Thank you." She smiled at Inko. "Good luck, Midoriya-san?" She started walking in the direction the doctor pointed out.

Inko smiled back. "Thank you." She turned to the doctor, nervously biting her lip. "So... what did you say about Izuku's Quirk Factor, Sensei?"

The doctor patted a nearby chair. "You may want to sit down for this." Inko nodded nervously, sitting down as the doctor suggested. The doctor pulled another chair around so that he could sit in front of each other.

"Quirk studies... is not an exact science. There are methods to detect the Quirk Factor in a person, but it's possible it can miss something, especially in a young child with an undeveloped Quirk Factor, and with how varied Quirks can be there's a lot we can miss or get wrong. Not to mention, there seems to be, for lack of a better word, a supernatural element to Quirks that we simply can't detect because it isn't physically present in the body. That being said, there seem to be a lot of discrepancies between the Quirk Factor tests we have for Midoriya-kun on-file and what we've done in-house. Now, we have more sophisticated equipment than a lot of hospitals and other practices have, due to our specialization and funding from the Speedwagon Foundation, but everything after the toe joint test seems to be completely off."

"Um..." Horror was starting to bloom on Inko's face. "The doctor... only performed the toe joint test?"

The doctor's demeanor immediately shifted. "He what?"

"He... said that if Izuku had the extra toe joint, then... then he couldn't..." Inko's eyes started to water. "I... I didn't even question it. I just..."

"Whoa! Hey, this is not your fault!" the doctor exclaimed.

"But I..."

The doctor put a hand on Inko's shoulder. "You went to a doctor for your concerns, the doctor gave you information, so you trusted them. It's not your fault that they lied, or were incompetent, or whatever!"

Inko sniffled. "Thanks. I... I still should've checked. If you don't mind, how does the toe joint test work?"

"Pretty much the other way around from what it sounds like you were told," the doctor explained. "Studies have found that it's incredibly rare for a person who doesn't have the extra toe joint to have been born Quirkless. However, there are certainly people with both the extra joint and a Quirk. In fact, it's incredibly rare for a first- or second-generation Quirk user to be born without the extra toe joint."

"So... Izuku might have a Quirk after all?" Inko asked hopefully.

"I... probably can't give you a definitive 'yes' to that, sorry," the doctor hedged. "We're going to be investigating the discrepancies, since it might be important to understanding his current condition, so we may have a more definitive answer later. I... wouldn't want you to get your hopes up if it turns out we're wrong, or if he's functionally Quirkless anyway."

"Functionally Quirkless?" Inko asked.

"Unfortunately, with how varied Quirks can be, not everyone can have a powerful, highly visible Quirk like All Might's or Endeavor's. 'Functionally Quirkless' is a term for people who technically have a Quirk, but for one reason or another they might as well not. It could be something so minor as to be near-indetectable, like being able to heat up objects by one degree if you concentrate on them over the course of an hour, too dangerous for your body to ever use, like your heart being an explosive, or with such an obscure and specific activation requirement that you may never find it, much less be able to use it reliably. I actually thought I was the latter until my late teens."

"Oh, I'm sorry," Inko said. "That... must have been hard for you."

He smiled. "Thank you. It... could have been better, I can't deny that."

"So... what kind of Quirk might Izuku have, do you know?" Inko asked.

The doctor shook his head. "Unfortunately, even with the best equipment we couldn't say for sure. We can tell how the Quirk alters the body, but a lot of the mechanism behind how Quirks work is still a mystery and thought to work on a level that we simply can't explain. Quirks work genetically, so we could hazard a guess based on the Quirks of recent ancestors, but there's always the potential of a random mutation."

Inko nodded. "Yes, that makes sense... What about his temperature, though? They said he was hot enough to burn things, that can't be normal. If his condition is related to his Quirk, then maybe it's fire-based! I... unfortunately couldn't find Izuku's father after he was born, but I know for a fact he had a fire Quirk."

The doctor blinked, then nodded. "That... seems likely."

"If Izuku is having some problem with his Quirk, do you have any way to help with that?"

"We do have a few things we could try. If nothing else, there's a pro hero that operates in Musutafu whose Quirk can forcibly turn off most Quirks, if it's some sort of feedback loop of misfiring Quirks then he could disrupt it and help Midoriya-kun figure out how not to do it. We've had him help out a few times before, it shouldn't take too long to get him in."

"What's the hero's name? My son likes a lot of heroes."

"His name is..."

ゴゴゴゴゴ

Aizawa Shouta felt very off. He wasn't sick or injured, but sometime after lunch he had started to feel a sort of pressure in the back of his head. Perhaps he had stayed up too late last night solving that annoying case, he thought. He was very tired, maybe he would feel better if he got some sleep. He didn't have any business he needed to attend to that night, so he had a quick dinner and went to bed early, promising himself that he'd get up early to do an early morning patrol.

His dreams were filled with the sound of music. It was a soft, stringed instrument, maybe a harp? Shouta felt like he was floating in a black void, unable to see even the nose in front of his face. "Where is that music coming from?" he wondered to himself. A sudden flurry of visions served as an answer! He saw himself many times over, all in different poses and locations! Each vision of him was holding an instrument that appeared to be made of some strange black metal. Most of the time it was a small harp, but sometimes it was something else, like a guitar, a flute, a trumpet, even an entire drum set! Each time, the vision lasted only long enough for the Aizawa Shouta of the vision to call out, "Prophet's Song!"

As the countless visions passed, Shouta started to hear singing in the background. "Now I know, now I know," his own voice sang in repeat, sometimes even overlapping as if multiple versions of him were singing about their knowledge. As the visions drew to a close, the voices started to sing a new word!

"Woah, woah, woah, woah, woah, woah, woah!"

Shouta jolted awake. He rubbed his eyes, then sighed. "Ugh, I really need to get better sleep..." He pushed his blanket off of him, jolting when he heard the musical thunk of a stringed instrument dropping to the ground! He quickly looked over to the source of the sound, seeing the strange black harp that he had just seen in his dream.

"What the..." he muttered, reaching for the instrument. It faded from existence before he could touch it. He frowned, then willed the harp to reappear. A cloud of black energy formed in his open hand, condensing into the same black harp. He grabbed the strange instrument on instinct, then experimentally strummed it. For the short moment that the music played, he could feel his vision double!

Shouta sighed. "I guess I have to learn how to play the harp now."

ゴゴゴゴゴ

A/N: Don't know how well I did, but I tried to channel a vibe like the one JoJo narrator for my narration for this.

Golly I wonder what could've happened to Izuku.

In case anyone was curious, Bakkuta comes from Bacta, the fluid in those healing tank things in Star Wars. Figured that'd be pretty fitting with BNHA's tendency to have places named after Star Wars things, even though they're usually places...

Because I couldn't think of a way to put it in without it feeling a bit clunky, the Quirk I thought of for the doctor is Crepuscule. As the name suggests (if you know what the admittedly obscure word means, that is), he can only activate it at twilight, specifically when watching the sunrise or sunset. To make up for the pretty glaring restriction, it's an incredibly powerful regeneration Quirk that basically sets him to perfect health no matter how bad shape he's in, with the exception that he specifically needs to look at the sunrise/set so if he's completely blind then he can't use it (which is pretty much the only thing saving him from AFO eventually trying to take it since his injuries left him blind). Probably Transformation-type, since unlike the more standard healing factor Super Regeneration it has to be activated. The reason why he didn't figure it out for so long is that he never watched the sunset or sunrise when injured enough to notice the sudden super-duper healing factor due to the fact that his parents were kinda strict with resting more when sick or injured (ironically enough...).