Chapter Text
Every teenager in Ground Gamma at the UA entrance exam knew about the Shooting Star Kid. Hell, even participants from other grounds had seen the bright light that flew upwards and decimated the zero pointer.
That’s what Izuku Midoriya is known as throughout the whole of UA: the Shooting Star. Yeah, it’s cheesy, but the name stuck like glue.
It’s all because of a quirk he wasn’t aware he had before getting One for All. A quirk so weak and small, so inherently useless, that no one had noticed existed until the day One for All made its home inside Midoriya and amplified his weak quirk factor, making it burn bright and strong – pun intended.
After all, a quirk that basically turns your bones into literal glow sticks wouldn’t be of much use to anyone looking to be a hero. Except if that person is Izuku Midoriya, a great analyst and all around quirk enthusiast. Even in Recovery Girl’s office, where he was getting checked in case any of his previously broken bones held any remaining fractures, he was already scanning through possibilities with this new development. All while ignoring the groaning and complaining of the dozen or so participants that had been blinded by the explosion of light that had been Izuku Midoriya and that were recovering all throughout the nurse’s office.
He goes home and tells his mom everything. They both celebrate over his new quirks, even though Izuku didn’t get a single point in the practical part of the test. He tries to contact All Might throughout the whole week, but to no avail. He spends it closed in his bedroom, filling an entire notebook with the different possibilities of his original quirk.
First of all: how does it work? Definitely not because of heat. Apart from the pain of breaking his bones, Izuku didn’t feel any burning sensation. Maybe bioluminescent? After doing some research, Izuku found the possibility of his bones being bioluminescent seemed highly unlikely. Bioluminescence was caused by the reaction of D-Luciferin and the enzyme Luciferase, which – combined with oxygen and ATP – caused a reaction that released the energy needed to produce light. Most animals with bioluminescence either glowed all the time due to the reaction, or could switch it on and off controlling the input of oxygen that the cells containing D-Luciferin and Luciferase received, thus controlling the chemical reaction. Since Izuku had never felt that kind of control over his body’s metabolism – or, for that matter, never glowed in the dark – he quickly disposed of the idea.
Although there was also the possibilities of his marrow being the only thing bioluminescent. When the outer layer of his bones broke, revealing the marrow – because, yes, he had managed to break his bones to the point that they almost looked like they had been through a blender – the glow would have shined through. That could work. But people had been blinded by the light, so the possibilities of his marrow shining that bright and not even glowing a bit – even through the outer layer of the bone and the flesh – was low. After all, he tried to test it by shutting the lights and windows of his bedroom and nothing happened. Not even a slight glow. But who knows, maybe the outer layer of bones is too dense for an intense light to shine through. To truly test the theory, he would need to do a bone marrow biopsy, and he didn’t have the resources to do that. Yet. If he got into UA – no, not if, when. WHEN – he could ask Recovery Girl for the analysis. He writes the possibility down in his notebook and moves on.
Up next: glow sticks. Another thing that shined when it broke. It could be possible that his bones were glorified glow sticks. Again, he digs into the depth of the internet and finds his answer. There are just two chemicals involved in the light of a glow stick: hydrogen peroxide and a luminescent (there are different kinds, but that doesn’t matter now. Maybe later, but not now). The two are separated by a container that breaks when you bend the glow stick, making them mix and the electrons go wild, causing the light. He turns back to his bone marrow. If it contains some sort of sac or compartment full of some luminescent, and his circulatory system had some sort of hydrogen peroxide variant/equivalent, that would explain why, by breaking his bones, the reaction would be triggered. Again, the theory could only be confirmed by a bone marrow biopsy. He just has to wait for UA.
Then there’s the third possibility of all this just being caused by a genetic condition that triggers his cells to glow every time his bones are dealt any damage, in which case this would be a one of a kind quirk and his research would have been completely useless. Well, at least he now has infinite knowledge of all things glowy.
What’s obvious is that One for All has amplified the effect tenfold because he has broken his bones before, and nothing like this has ever happened. So the stockpiling effect of One for All was grater than imagined. Well, that was pretty obvious from the condition of his bones. Izuku shivers just imagining what would have happened if he hadn’t spent all those months training at Dagobah Beach and then trying to use the quirk.
Well, better move on. How to put this quirk to use. Hmm… breaking his bones every time he wants to use it seems extremely inefficient. If anything, he could always use them as a flash grenade in the worst-case scenario. Or as light-sources in rescue missions. Then again, breaking his bones is less than ideal. Maybe he could get some kind of cell-infused weapon that could help with that? There have been several cases of support agencies using hair or cells from heroes to create their costumes so they could use their quirk without problems. Like the permeation guy from the UA sports festival two years ago. After he flashed the hole nation, UA made sure his sport’s uniform was made with the same fibers as his hair, so maybe something similar could be used to create a weapon for Izuku. But again, he could only do that when he got into UA. Ugh! He loved working with hypotheticals, but right now, he needed answers!
When the UA letter finally arrived, he went to open it privately in the dark of his room. He threw his research and notes on his bed and placed gingerly the white envelope on the table. This moment could decide his entire future. He took a deep breath and ripped the letter open, and a small disc fell into the surface of the table.
First instinct reaction: a bomb. So Izuku dove behind the chair to protect himself from the blast as best as possible, and prayed for the detonation to not be strong enough to damage the foundations of the building.
When All Might’s booming greeting reverberated through the room, Izuku picked his head out from behind the chair and was pleasantly surprised to find a hologram of his mentor instead of a scorch mark. Now more at ease, his settled down on the chair as All Might explained the ruse of the entrance exam and his final mark. 50 points were… a lot. Even though they had to subtract him points for blinding half the participants, it was enough to pass.
With tears in his eyes, Izuku listened as All Might himself welcomed him into his hero academia, and even after the hologram ended, he stayed in the dark, crying and smiling from relief and amazement. He had done it. He’d finally done it! He got in, under All Might’s wing of all things, and discovered he had a quirk of his own all along. All things considered, life was going great.
He met his mentor on Dagobah Beach, now clean and being enjoyed by Musutafu citizens, and started the conversation strong.
“Umm… so… about the glowing bones… I don’t really know where that came from.” Izuku said sheepishly.
All Might chuckled and patted his head. “Don’t worry, my boy, I understand that a quirk like the one you seem to have wouldn’t show up before.”
“But-“
“We’ll figure it out with Recovery Girl back at UA, don’t worry.”
The man gave him a blinding smile and Izuku couldn’t argue. After all, his plan had been this all along: get into UA, talk to Recovery Girl, and get a bone marrow biopsy. He’ll just have to wait until the first day of UA.