Chapter Text
Prologue: Born Different
In a clinic in the central district of Musutafu, a mother and her son were waiting to be called in for a simple Quirk check-up.
The waiting room was quiet in the way medical places always are—too clean, too still, as if even sound was careful not to linger.
The child was vibrating with excitement because he knew he had a cool Quirk. His left arm was metal, and it felt cool to the touch. He had also had an X-ray taken that showed there was metal inside his body as well.
Izuku Midoriya was his name. Born to Inko and Hisashi Midoriya, he was their bundle of hyperactivity.
The door opened, and out stepped a rather rotund man with round glasses.
“Izuku Midoriya?” he asked.
Both green-haired Midoriyas stood up and entered the room.
After a brief exchange of words Izuku didn’t care to fully pay attention to, he was taken through a few tests. Another X-ray to compare with his first, some blood tests, and a few other evaluations he didn’t fully understand.
Eventually, the doctor reached his conclusions.
“Your Quirk is rather peculiar, both due to how it’s manifesting and what it’s doing to your body,” he said.
Inko looked concerned. “What does that mean?”
“Well,” the doctor continued, “your son shows traits of a mutation-type Quirk, but his internals suggest something closer to an emitter-type.”
He paused briefly before continuing, his tone becoming more serious.
“There is also something very concerning I’ve noticed—his digestive tract has either shrunk, or more accurately, remained the same size it was when he was a baby.”
Inko looked worried for her little boy.
“That explains the small appetite and stomach aches… what should we do then?”
The doctor adjusted his glasses slightly.
“Well, I did some unconventional research in the past, and this points to a form of blood-based Quirk. I’ve had a few ‘vampiric’-type cases come through before.”
The doctor opened a medical fridge and pulled out a blood bag. He carefully dripped some of its contents into a paper cup.
“I need you to drink this. If I’m correct, you should feel better after about five minutes.”
Izuku hesitated, his hands shaking at the thought of drinking blood.
After a moment of uncertainty, he relented and shakily took a sip. A small amount spilled onto his cheeks and neck.
Almost immediately, the droplets vanished into his skin, as if being absorbed. The doctor stared at the reaction in visible confusion.
Izuku, meanwhile, blinked in surprise.
Instead of the coppery, metallic taste he expected, he was hit with something sweet and strangely fragrant.
“…That kind of tasted good?” Izuku said, confused.
“Well, it seems like we have a vampiric sub-type in there as well. Tell you what—call this number and register with the Vlad-King Blood Drive Program, and tell them it’s dietary related.”
He pulled out a card with a phone number on it and handed it to the mother.
“It will cost about 20,000 yen a month for forty packs of blood, plus a registry fee. You’ll receive deliveries in about twelve to sixteen hours.”
He paused briefly before adding, more casually, “It’s the safest option for cases like this.”
Thanking the doctor, both Midoriyas left for home.
Inko’s mind immediately turned to finances and the special needs Izuku would require moving forward. Meanwhile, the green-haired boy thought about what his Quirk could do.
///
Quirk Registry: Izuku Midoriya
Type: Emitter / Mutation Hybrid
Known Constraints: Hemovoric physiology
Quirk Name: Cybernetic Vampire (Temporary Classification)
Description:
The user was born with an underdeveloped digestive system, resulting in food intolerance. The left arm is entirely metallic, featuring an internal hydraulic system and redirector plates integrated into the hand.
The user also possesses several biomechanical organs formed within the chest cavity, most notably a blood-processing device that converts blood into usable energy and raw material.
This material is what forms the metallic portions of his body. Interestingly, the “steel” that is produced is both flexible and porous, allowing blood to pass through it.
Any attempts to replicate the material have proven futile.
///
It had been more than a decade since then. Izuku had grown both in stature and in Quirk.
Walking out of his room and toward the bathroom, a set of four wings protruded from his back—inactive. His limbs had largely become augmented, leaving almost no actual flesh exposed to the outside.
While showering, it became clear how much had changed.
His thorax was entirely covered in alloy armor, while the rest of his body remained partially organic. Moving upward, his neck consisted of exposed servos and pistons, and even his jaw had been replaced—giving him a Metal Gear Rising: Revengeance-like Raiden appearance.
In the time between the Quirk diagnosis and now, many things had changed.
For one, his stomach was entirely gone, leaving behind empty space.
Another change was the wings.
They could be shut on and off at will, although at the cost of some energy. They could also display his emotions through position and color.
Red meant annoyed or angry.
Green meant discomfort or disgust.
Yellow was neutral—and by far the most common.
Blue meant fear or caution.
Dark red was also an option, but that meant he was pissed off, and it was always accompanied by a low whirring sound from within his chest.
That had only happened once, when a group of bullies ganged up on a transfer student. Safe to say, it ended with the bullies getting a good punch to the gut.
Bakugo, unlike in many other stories, was good friends with Deku, though he was still hot-headed and brash.
Another change, which was particularly annoying, was “Combat Mode.” In this state, his visual perception would drop in quality while his brain began processing information at extreme speed—effectively at “Mach 8” levels.
He could control it to an extent, but getting startled would automatically trigger it.
In this state, his brain would begin processing the world as a low-polygon version of reality, and his wings would shoot out to either side.
He theorized that this was to reduce processing load by filtering out unnecessary detail and prioritizing only the most important information first.
This state would consume significantly more blood than passive mode, as his brain attempted to conserve the most important resource to him.
He had finished using the bathroom and went to the kitchen and pulled a bag of blood and drank it.
His mother had been called into work early, so she had left the food for him before leaving.
His father was stuck in America for an undetermined amount of time, meaning he could only ever communicate through video calls.
‘Alright just another week of school and winter break would start’ he thought to himself
///
Later, after school, he had elected to walk home alone since Kachan would be goofing off at the local arcade as always.
Passing under a bridge, he heard a manhole cover rattling before a mass of green sludge shot out of it.
It turned to look at him, bearing yellow, misshapen teeth.
“OOH, A FLESH PUPPET WITH A GOOD QUIRK!” the villain spat out as Izuku realized what it was.
Izuku crouched into a fighting stance, and his wings snapped outward, ready to fight.
Combat target identified:
Caustic ooze
Greater Villain
His internal systems designated it and prepared for engagement.
“Bring it,” Izuku said, his voice slightly modulated.
///
The mass of sludge lashed out, a tendril whipping toward the verdant-haired boy.
It was deflected by a +PARRY, followed immediately by a +DISRESPECT as Izuku unleashed a flurry of punches straight into the creature’s eye, stunning the villain.
This DESTRUCTIVE level of damage was elevated to CHAOTIC when he shattered the villain’s teeth with a +DROP KICK, causing a +GUARD BREAK.
The villain recovered quickly and became +ENRAGED at the teen’s antics, spreading its form out in an attempt to encircle the winged boy.
Izuku responded by leaping upward and dashing backward, narrowly avoiding the encroaching mass of sludge.
“Don’t have anything to deal with an amorphous villain,” Izuku thought to himself before noticing the manhole cover being flung from its spot.
“DO NOT FEAR, FOR I AM HERE!!” yelled the Number One Hero as he unleashed a wave of high-pressure air toward the sludge man, dispersing the villain instantly.
Even in the reduced detail of his vision, the massive frame of the Symbol of Peace—All Might—was unmistakable.
Izuku landed and quickly disabled Combat Mode before running up to the hero.
“Thank you, Mister All Might! Can I get your autograph?!” was what he wanted to say—
but what actually came out was:
“THANKYOUMISTERALLMIGHTCANIGETURAUTOGRAPH?!”
“What?” was the only thing that came out of the hero’s mouth as he stared at the hyperactive teen he had just helped.
“Sorry, I just need to slow down.” Izuku took a deep breath before speaking again, much more clearly.
“Of course, young man—what’s your name?” All Might asked, accepting the notebook and pen.
“Izuku Midoriya. I’m a really big fan.”
All Might could tell. He quickly wrote his signature in the boy’s notebook and handed it back before pulling out an empty bottle and collecting the sludge villain.
“I need to go now, young Midoriya! Do take care on your way home!”
And with that, he leapt into the horizon and disappeared.
///
Izuku was beaming with happiness on the way back.
He had met All Might, of all people. He would have asked more questions, but the hero had obviously been in a rush.
His metal feet tinked softly against the ground as he walked at a calm pace.
He had one hell of a story for Kachan.
///
Toshinori had just finished handing the sludge villain over to the authorities. Now in his smaller form, he sat in a quiet café, idly nursing a cup of coffee.
He had his phone out, searching up the Quirk registry of the young boy he had encountered earlier.
‘So… his body is slowly mechanizing, he needs to consume blood to function, he can accelerate at ridiculous speeds, and he can adjust his perception of the world to reduce cognitive strain,’ he thought as he read through the registry.
‘Kid’s got potential, but the drawbacks are challenging, to say the least,’ he mulled over the boy’s Quirk and related history, thinking about public perception if the kid ever pursued heroics.
Blood dependency alone would raise concerns.
‘People don’t like what they don’t understand… and they like it even less when it sounds dangerous.’
///
Deku had been training at Dagoba Municipal Beach for a few months, using it to test and refine techniques he had come up with.
The beach was little more than a dump. Ocean waves pushed in mounds of garbage from the sea, and people illegally added to it, turning the area into a wasteland of debris.
Despite that, it had become a hotspot for people training and young inventors looking to get their hands on useful materials. Since the beach was far enough away from the city, local law enforcement allowed Quirk usage there in exchange for helping clean it up.
Izuku had been practicing his wall-hopping and sliding abilities, focusing on increasing his speed.
He had figured out that sliding just before hitting the ground allowed him to chain jumps and slides together, making it an efficient way of moving.
Another discovery was that if he jumped off a wall while “slamming,” some mechanism in his legs would store kinetic energy and release it the moment he touched the ground.
This, in turn, would launch him into the air or send him rocketing off in a chosen direction.
His wings were not meant for flying—he had figured that out early on. The first time they sprouted, he had jumped out of a tree, only for them to flop uselessly behind him. He had ended up dashing forward instead, completely canceling his vertical movement.
Another discovery was that his wings could store objects while active. Items would flash away in a burst of light and drift toward his wings before disappearing.
Strangely, there didn’t seem to be any limit, nor did the stored objects have any noticeable effect on his weight.
///
Izuku was collecting bags of trash, pushing his strength to its baseline limit—around 200 kilograms of lift. In his active state, he could reach far higher levels of strength, though at a heavy fuel cost.
Tossing the plastic bags into a large industrial dumpster placed nearby, he turned—
just in time to see a pink-haired girl rapidly falling from above, some kind of equipment strapped to her back.
“Shit! Need to move—”
Thinking quickly, he performed a slam storage and launched himself upward, intercepting her.
He caught her by what he now identified as a jetpack and splayed his wings out to slow their descent. Finishing the maneuver, he dashed forward to cancel out their fall, landing in a cleared section of the beach.
“You alright—?” Deku asked—
only to be tackled by the same girl he had just saved.
“THAT WAS AWESOME! HOW DO YOUR WINGS WORK? ARE YOUR INSIDES METAL?!” the pink-haired engineer blurted out at incredible speed.
Izuku froze for a fraction of a second, Combat Mode threatening to activate from the sudden impact before he forcibly suppressed it.
“Wha—hey, wait—!” he managed, slightly muffled as he tried to sit up.
The girl showed no intention of getting off him anytime soon.
She had bright pink hair tied back messily, goggles perched on her head, and a half-assembled support rig still strapped awkwardly to her back. Tools jangled lightly as she moved, like she had been working on it seconds before falling out of the sky.
Her eyes were wide—bright with obsessive curiosity.
“I’m Mei Hatsume!” she announced. “Support gear inventor in training! And you—YOU are amazing!”
She leaned closer, completely ignoring personal space boundaries.
“Those wings stabilized your descent AND corrected your momentum mid-air! That’s not standard Quirk flight behavior at all!”
Izuku blinked.
“…Huh?”
Mei didn’t wait for a response. She pushed herself up slightly, immediately scanning him like a living prototype.
“You’ve got mechanical integration all over your body, right? That’s not just mutation-type restructuring—that’s layered augmentation! Are your wings biological support structures or externalized systems?!”
She paused, eyes practically sparkling.
“Wait—can I touch them?!”
“Wait! Hold on a sec, you were about to go splat against the ground, I feel like you should be more concerned about that than me”
The pink-haired menace was practically vibrating. Why did this remind him of himself when he was a kid?
In an exasperated tone, he replied to the pinkette’s questions.
“Name’s Izuku Midoriya. Yes, my Quirk is slowly turning parts of my body into metal alloys. Yes, my wings are natural. No, I’d prefer not having my appendages examined by a random girl I just saved.”
“Aww, man, just a little peek inside?” the pinkette pouted.
“What were you even doing in the first place? You could’ve hurt yourself if I wasn’t here!”
“Oh, just testing out my newest ‘baby’,” she said, pointing to the smoking pack on her back.
“Also looking for good material to fix my other babies.”
They ended up talking about her inventions and his Quirk, trading ideas and explanations in bursts of rapid technical curiosity.
Mei moved between excitement and analysis so quickly it was hard to tell where one ended and the other began, while Izuku found himself answering more honestly than he expected.
Eventually, after what felt like both five minutes and an hour, she pulled out her phone.
“Exchange numbers,” she declared.
“…Huh?”
“So I can call you when I need a test subject! And you can call me when you need support gear! It’s mutually beneficial!”
Izuku hesitated for half a second.
Then, slowly, he handed over his contact.
‘This is either a terrible idea… or the start of something useful,’ he thought.
Mei grinned immediately after saving it.
“Great! First official field data partner!”
Izuku blinked.
“…Field what?”
But she was already half-turning away, mentally designing something new before she had even left.
He watched her go for a moment.
Then exhaled lightly.
‘She’s… a lot.’
Still.
Strangely useful.
He looked down at his phone.
One new contact saved.
Mei Hatsume.