Midoriya Hisashi breathed fire. Izuku wanted to be like him once, exhaling gouts of flame like a circus performer. He’s okay, he thinks, with what he is. It may not be a firebreather, but it’s him.
His eyes are bright and twinkling, his skin practically glows. Everything about him is bright.
Midoriya Izuku is full of stars.
When Izuku is four, his mother, Inko, takes him to the hospital to see a Quirkologist. Four is the year that quirks often begin to express themselves, and as far as Inko can tell, Izuku has shown no signs. He certainly hasn’t attracted any objects the way she can, and thankfully, he has not set fire to anything with precocious fire breathing.
The Doctor sits Izuku down in a chair, and begins a basic check up to start off with. Blood pressure, heartbeat. He puts a standard thermometer in Izuku’s mouth to check his temperature, instructing him to hold it under his tongue and to leave it for several minutes.
(Little Izuku being Little Izuku, he huffs and he puffs and does his best to summon up the flame within)
In retrospect, he probably should’ve been tipped off the moment Izuku complained of a funny taste in his mouth. Regardless, when the Doctor went to remove the thermometer from Izuku’s mouth, only half of it came away in his hand.
Ruefully, the Doctor realises that he should’ve stuck to protocol and used the Quirk Thermometer. It was a mistake to think that just because there was no outside sign of fire or thermal activity, that the boy wasn’t capable of it.
They schedule more tests. Scans. Thermometers of increasing heat tolerance. It’s starting to become something of a circus, and Inko does her best to remain calm throughout all of this. Izuku, for his part, is just curious.
Ultimately, they conclude that Izuku has inherited a mutated version of his father’s quirk - not particularly uncommon. Most of the terms go over Izuku’s head, but he tries his best to follow along. What he gets is that his father’s stomach made a spark of electricity and that this ignited the gas already produced.
Izuku’s stomach ‘ionizes’ it into plasma. Compared to his father, this is apparently the difference between a drop of rain and an entire monsoon. As a side effect, they note that Izuku can consume things a baseline human probably shouldn’t - like mercury filled thermometers.
Later, in primary school, Izuku learns that stars are also made of plasma. He’s delighted to be full of stars, and he imagines entire galaxies swirling in his gut.
Since learning of his Quirk, he’s taken to eating odd things. His mother isn’t sure if she should stop him or not - chewing on metal is normally not okay, but knowing that it’ll have no adverse effects on him changes that. Belatedly, she ends up telling him not to eat random things. If he’s going to eat metal, he can purchase it from the hardware store.
Visits to the hardware store become something like visits to the candy store, where an excited Izuku buys handfuls of nuts, bolts and screws to snack on like they were trail mix whilst a bemused Inko watches. The staff soon adjust, and are always happy to see their cutest customer.
Iron has a tangy flavour to it, sort of but not quite similar to a sour candy, that Izuku finds he enjoys. Nickel has a creaminess to it, though he finds copper bitter and the less said about tin the better.
Kacchan asks him why he’s chewing on bolts once. “Because it’s tasty!” is all Izuku says. Kacchan tries a bolt, and spits it out, but Kacchan also likes really spicy food so Izuku’s not sure he has taste buds anymore.
Izuku is seven the first time he vomits.
His mother takes him to a carnival, and he’s so excited he almost vibrates out of his chair. There’s carnival food, although Izuku has already eaten a few ingots worth of metal, and then there are rides. Izuku’s fine until he takes a ride on something called ‘The Twirler’.
It twirls alright. It twirls so hard and so fast that when it finally stops, Izuku stumbles a few feet and Inko wisely guides him towards a bin. When he retches, it suddenly occurs to her that perhaps a person whose quirk involved plasma in their stomach should not be made to vomit the contents of said stomach.
Fortunately or unfortunately, it’s too late to even warn Izuku, even if it's too late to reach the bin.
His vomit is not what anyone expects. It is certainly not chunks of half-digested food, swimming in bile, and for that, everyone is a little thankful, Izuku included. It is not a burst of superheated air and plasma, and for that, everyone should be thankful (alas, only Inko is aware of the potential danger, and she is the only one who is properly relieved). It is, instead, a small white hot gooey mess that begins to cool almost immediately after leaving Izuku’s mouth.
Inko knows better than to touch it, but Izuku doesn’t. He reaches out with his childish hands and scoops it up. Inko wants to tell him not to, to let it go because grabbing your vomit is very much not a polite thing to do (and certainly not hygienic), but the rest of her is still unsure what parts of normality still apply to Izuku, so she ends up only watching as the still slightly nauseous Izuku begins playing with the substance, rolling it into a ball as it cools.
In short order, he’s holding a somewhat spherical blob of silvery metal.
It stands to reason that the boy who eats metal also pukes metal. Inko shouldn’t be so surprised at the things Izuku does, but he always seems to find a way to simultaneously worry and impress her.
Inko takes the metal to a Quirkologist, who after initial testing, suggests she’d be better off seeing a geologist or some kind of engineer. Metal byproduct isn't incredibly rare but it is uncommon, and they don't have the facilities to test the qualities of the metal.
Izuku’s weird puke-metal turns out to be a steel alloy made up of the various metals he enjoys snacking on. That in itself isn’t so remarkable, but after more tests, it turns out to be a surprisingly useful metal. The Engineer she sees professes it’s usefulness, bandying terms she herself isn’t too familiar with - coefficients, scales. Her degree was in social services, not metallurgy. She thinks she gets the gist of ‘Shape-memory alloy’ though. The general meaning seems to be that whatever weird metal Izuku made is quite useful, and could she possibly tell them the source of it?
She politely refuses, citing personal reasons. She doesn’t want to open up her son to that kind of scrutiny or pressure. When he’s older, he can decide. They’re disappointed, but understanding. They ask to keep the metal. Inko checks with Izuku, and he agrees. He can, after all, make more. Surely?
Izuku does make more. He learns to shape them into figurines, little models of animals and people. Blobby, indistinct models but each one he makes gets progressively more detailed. Shaping the blobs of metal with his fingers is hard though, so soon he learns to shape tools out of the metal first.
It only takes him a few weeks to learn that he doesn’t have to vomit to make the metals - chewing works just as well, but it does take a little longer. It’s a lot more pleasant a sensation too; akin to chewing gum.
Izuku runs lots of tests on his metals, creating rudimentary scales of his own. They are, for the most part, quite similar, although he finds that if he adds more zinc, he creates a ‘harder’ metal. Less malleable. Copper makes for very conductive metals, but they are also soft and squishy compared to the others.
Inko is kind enough to let Izuku take over the garage, and he turns it into a workspace for all his figurines and tools. Particularly pretty and well made ones get put on the mantle.
He asks Kacchan if he thinks he can be a hero. Kacchan takes one look at him and snorts.
“What would you do, Deku? Spit metal at villains?” And goes right back to blasting rocks across the lake.
Izuku frowns, but he can’t say Kacchan is entirely wrong. The stars are all inside of Izuku. He has no way to get them out. Heroes like Endeavour can make the fire from any part of them. Izuku can’t even cough it up if he tries.
He stuffs a handful of lake sand and gravel into his mouth to take his mind off things. The gritty texture is nice, even if the overly sweet flavour isn’t Izuku’s favourite. He has a blob of glass to play with soon enough, and he makes it into a small starburst.
“For you,” He says as he hands it to Kacchan. It’s got a soft gold tint to it but the center remains a flare of orange, and it very much reminds him of Kacchan.
Kacchan takes it with only mild hesitation.
Izuku stares down at his collection of handmade figurines and baubles.
He can’t be a Hero like All Might or Endeavour or Kacchan. But Izuku knows Heroes. He loves them. He’s wanted to be like All Might since he was even aware who All Might was.
But, he thinks, it’s okay that he can’t be like All Might. Kacchan is better suited to being like All Might than he is. Although, Kacchan’s attitude makes him more like Endeavour than All Might. He'd never say that to his face though, not without being prepared to run for a good handful of minutes.
Izuku is full of stars, and he can’t get those stars out of him in a way that is immediately helpful to Heroics. But he can get them out - in his metals.
Plenty of Heroes rely on devices or gadgets meant to assist or amplify their abilities. Rather than being like All Might, couldn’t he be someone like Power Loader? Heroes have a dangerous job. Couldn’t his metal make that job just a little safer?
Nodding his head, he starts to work on his very first project - a shield.