Chapter Text
Midoriya Izuku was born green. As a changeling, his quirk was active from the moment he entered the word, changing his biology drastically. His light dusting of baby hair was dark green, his eyes were bright emerald, and a few forest-green freckles dotted his light green skin.
His mother blamed his father’s name, Midoriya, for this. Greenvalley was such a stupidly prophetic name in her opinion.
His father blamed his mother’s hair for this. Natural green hair that wasn’t from her quirk? An omen for sure.
“A combination and mutation of both of your quirks,” said the doctor, blaming science. “We can only know quite what has happened here once he matures, but we will keep him under observation for a few days just in case.”
()()()
The green baby revealed its quirk within hours, refusing to consume any of the milk or formula provided to it. After a battery of tests, it was revealed that the baby was photosynthesizing, absorbing nutrients from the sun through specialized skin cells and a unique lining in his throat and lungs. The doctor’s concluded this was a mutated combination of his parent’s quirks: attracting small objects (in this case particles of light) into his modified throat (the fire-breathing aspect instead drawing on the ‘fire’ of the sun) and metabolizing it for energy. The family was sent home a few days later with instructions to keep their family doctor updated on any new developments in the child’s quirk.
()()()
A baby that required no breast-feeding periods was a godsend to Inko, letting her return to work much faster than she would have. Her job as a secretary did not allow enough breaks for regular feeding but had no problem with her merely keeping a baby at her desk. Inko’s swift return to work helped her family’s finances greatly, and when the opportunity for a promotion to an American branch came around for Hisashi, he was able to confidently turn it down to continue working near his family.
Little Izuku was an incredibly energetic child, never seeming to run out of energy during the day. His lack of need for naps made having him at work even easier, and he would pass out almost instantly after sundown without any fuss. The Midoriya’s enjoyed some of the most peaceful baby years imaginable, much to the envy of Inko’s best friend: Mitsuki’s baby was a terror to behold, screaming constantly and thrashing about as though his rage could manifest his will faster.
As the two children became toddler’s the women socialized them frequently, more and more as little Katsuki proved to have enough energy to keep up with Izuku most of the time. Katsuki still needed occasional naps though. The boys’ childhoods passed swiftly and uneventfully, until pre-school when their quirks started to come in.
()()()
Now, most people thought that Izuku had already gotten his quirk. The boy could eat sunlight after all, it didn’t seem reasonable that there would be more to it than that. Just a standard mutation. So, when Katsuki’s quirk came in and granted him explosive palms, he lorded it over the green boy.
“My quirk is soo much better than yours” Kachan cackles as his palms crackle, running in circles around Izuku. “Can your quirk make you fast like this?”
Izuku frowned, feeling for the tingling in his chest that had been bothering him for the last few weeks. He takes a deep breath reflexively as Kachan passes him, and suddenly feels strength rushing through his body. For a moment, tiny golden motes of light seem to float in the air and following the inward pull of his breath before vanishing into the boy’s throat. Izuku takes a tentative step, then another, then thirty more, running across the park faster than the staccato explosions of the other boy could propel him.
“Look Kachan!” he shouted gleefully, “I can go fast like you! I just needed more sunshine!”
“Holy crap!” The other boy shouts, “That’s awesome Izu! We are going to be the coolest heroes ever!!”
()()()
A week later Izuku decided to test his resistance to fire, begging Kachan to hit him with a strong explosion. The explosive boy gives in, blasting him point blank and flinging Izuku across the playpark. Much to their shock, by the time Izuku has hit the ground the burn and scorch marks are gone. Golden motes dance as the plant boy pants heavily, skin already smooth and unblemished.
“.. I’M INVINCIBLE!” Izuku screams happily, ‘HIT ME AGAIN KACHAN!”
A few minutes away, in the kitchen of their modest house, Inko Midoriya shivers. For some reason she has a feeling her life is about to get a lot more stressful.
()()()
The boys enter elementary school as fast friends. Izuku is so high energy none of the other kids want to play with him, unable to keep up with the infinitely energetic teen. It isn’t any fun to play tag with someone who can completely re-vitalize themselves with a few breaths after all. Izuku’s only companion is Katsuki, his quirk raising his blood pressure and making him nearly as energetic, body constantly pumping with adrenaline. Explosion does not grant the boy any additional stamina, but what it lacks Katsuki makes up for in pure grit and determination. The boy’s parents have resorted to letting them loose for hours at a time in the park beside their house, and recess at elementary school often devolves into the two running near marathon (relative to their age) games of tag around the playground as they scream and throw themselves across play structures.
It is during elementary school that the true extent of Izuku’s regenerative abilities are revealed. The two boys are playing on a bridge, happily roughhousing and glad to be in a new environment, their mothers following along behind them at a more sedate pace. Izuku hops up onto the wall of the bridge, balancing precariously as he shows off his balance to his mother and pseudo-aunt.
“Look Mom!” the small green child calls, “No hands!”
“Izuku! Get down from there this instant!”
Izuku goes to hop down, and trips on a rock. He teeters for a moment, his mother and Katsuki rushing towards him in an attempt to stop the inevitable, and then he tumbles off the bridge. The green boy falls limply through the air for a few heart-stopping seconds, then catches his head on a sturdy branch, leaving it behind as his body thuds into the floor surprisingly intact. Inko screams in horror, hurrying down the sloped banks towards his body, tears streaming down her face.
By the time Inko reaches the bottom, Izuku’s head has dissolved into brown and crispy plant matter, and his neck is shimmering with golden light as a replacement grows back. Moments later, he sits up looking no worse for wear.
“Mom!” he says excitedly, “My head popped off! Then it popped back on! That’s so cool!!!”
Inko just sobs, holding him close and wondering how her life had ended up so strange.