Hi everyone! I'm a long-time original fiction writer and first-time fanfiction writer, though I have been reading fanfics for ages. Look - I saw Infinity War, I'm Sad™, I decided to work out my feelings by writing out an idea I've had for a while.

Before we get started:

1) I should mention that this story will deal with experimentation on children, and torture. I could just be jaded by the world, but I don't think it's any worse than what's already canon in the MCU.

2) Also, this is a slow burn, for reasons which will be pretty obvious, but we'll get there eventually. I promise.

3) The events of CA:TWS start in chapter 11 if you feel like skipping ahead, though you will be pretty confused.

I hope you enjoy!

PS: I know I'm playing a bit fast and loose with biological clocks here. Howard Stark would be 69 years old in 1986, but Maria doesn't have a listed date of birth in the MCU wiki, so for the sake of this story she's going to be around 50 - by no means a spring chicken, but still likely to have a healthy baby with the best help that 1986 science has to offer.

Updating twice weekly.

Edit: There's now a 'The Wyvern' playlist! Can't post links on this site, but if you head to the 8tracks website and search for 'The Wyvern,' it'll come up. I've got the same username over there, and there are 22 tracks. Enjoy!

June 2nd, 1986
Stark Mansion, Manhattan

"Hey, Tony? You in here?" James Rhodes poked his head through the door of Howard Stark's workshop, smoothing back his jacket. He'd been to the mansion before, but only ever with Tony to show him around. Today he'd come because Tony hadn't returned to MIT after the weekend, and wasn't picking up the phone. So Rhodes had driven himself on down to New York to check on him. He was nice like that. Of course, he'd started feeling less nice and more like a visitor to a foreign nation when aides and assistants and a very suspicious butler questioned his intentions and then finally let him into the workshop.

Of course, there Tony was: sitting cross-legged on the floor in the middle of the enormous workshop, peering down the length of a metal tube with a torch in his mouth and a screwdriver in his hand. He looked like he hadn't slept or washed in a day or so; his mop of dark hair was straggled across his forehead, and there was a large oil stain on his sweater. A warzone of metal parts, tools and wiring radiated out from where he sat.

"I don't know why I bothered," Rhodes sighed, picking his way through the mess of mechanics.

The genius sixteen-year-old finally glanced up, and Rhodes saw the redness in his eyes. "Rhodey!" Tony mumbled out around the torch in his mouth, then dropped the metal tube on his foot. "Ah, shit."

"Hey Tony," Rhodes greeted, then squatted down by his friend. There was a boxy computer hooked up to parts of the machinery, running lines of green code. "You get caught up in your robot again? Forget which day of the week it is?"

Tony shrugged, and finally took the torch out of his mouth. "Nah."

"You weren't answering the phone."

Tony looked over his shoulder, and Rhodes followed his gaze to see the workshop phone hanging from its cord. "Ah. That'd be why, then. Come on, man, what gives?"

Tony picked up a circuit board and began attacking it with a soldering iron. "My mom gave birth today."

"Holy shit!" Rhodes exclaimed. He hadn't even considered that as a possibility for Tony's absence, and he'd heard of little else over the past nine months – not so much from Tony, who got ornery and mouthy whenever it was brought up, but the news (and many of their college professors) were excited by the prospect of another Stark child. Especially so late in Howard's life, the kid was being hailed as a 'miracle baby'. Rhodes privately thought it would be a miracle if Tony and his new sibling got through their respective childhoods without multiple complexes. "And it's… I mean… is it…"

Tony rolled his eyes. "It is a girl, they called her 'Margaret Abigail Stark.'" He snorted. "It's an old lady's name."

"It ain't much better than 'Anthony'." Rhodes was rewarded when Tony threw a bolt at him without looking up from the circuit board.

"I heard them arguing a few weeks ago about girls names, mom asked him to name one woman he hadn't slept with." He snorted again, and then hissed when the soldering iron nicked his finger. "I guess they went with that theme."

"Did you go to the hospital?"

"Nah. Dad called and told me to come visit, but…" Tony gestured at the dangling phone, and then at the chaos around him. "I'm busy."

Rhodes sat back, narrowly avoiding knocking over the computer, and watched his friend mangle the circuit board while pretending to repair it. James Rhodes was not a genius, as he was reminded nearly every day, but even he recognised a faulty solder joint when he saw it.

"Hey Tony," Rhodes eventually said, cocking his head.

"Yeah?"

"You stink. Go get in the shower, and I'll track down your weird fancy butler and get him to make you a cup of coffee."

Tony's eyes narrowed. "What then?"

"Then I'm going to drive you to the hospital. C'mon," Rhodes got to his feet, and offered Tony a hand. Thankfully he took it, only narrowly missing taking out Rhodes's ankle with the soldering iron. "Alright, buddy. You're going to meet your sister."

It didn't turn out to be as much of a disaster as Rhodes expected, after nine months of surly looks and underage drinking.

He made supremely awkward small talk with Howard Stark in the squeaky corridor of the hospital, trying to get glimpses through the door of Maria Stark's private suite. The antiseptic hospital smell made him nervous, and Howard Stark talking about Tony's "potential" made him doubly so. He did manage to get a few glimpses of Tony holding what must have been the baby, though – Tony peered down at the bundle of blankets with an unreadable look, arms stiff and feet shifting. Rhodes had seen him hold a flaming carburettor with more comfort. And possibly more affection.

Later, when Tony finished updating his dad on the progress of the robot, they walked out of the hospital and back to Rhodes's car.

"Well?" Rhodes asked, jangling his keys in his pocket.

Tony wrinkled his nose. "She was purple. And wrinkly. And like, completely bald. I'm going to have an eggplant for a sister."

Rhodes laughed, and laughed harder – mostly in relief – when Tony joined in. "I'm pretty sure that goes away, man. I saw my sister's baby a couple years back right after it was born and it looked like an alien. But he's mostly normal now."

"Mostly?"

"Well he won't shut up about E.T., so you never know…"

A few months later Tony's robot – of course – won him the MIT Robot Design Award. He got in the paper, and that sparked a new wave of excitement about the "future of Stark weaponry". Tony and Rhodes mostly spent their time in class, or crashed frat parties and either got kicked out when someone recognised Tony and remembered he was only sixteen, or got offered more beers. Rhodes had also started a pre-Officer Training weekend program with the Air Force, so Tony ended up back in his father's workshop in New York more often than not. One Sunday Rhodes once again found himself being ushered into the mansion and interrogated by the nosy butler.

"I'm starting to think this workshop is foreign soil or something," Rhodes called as he strode toward the door. But he stopped in his tracks when he heard something he did not expect to hear coming from the workshop: laughter. And not Tony's laughter, or even Howard's (which Rhodes did not think he'd ever heard in his earthly life, so you never knew), but a baby's. Rhodes crept up to the workshop door and peeked inside.

The scene before him was like a bizarre family portrait: Tony's robot was bolted to the floor in the middle of the workshop (which was a lot cleaner than the last time Rhodes had visited). Rhodes had seen the thing in action plenty of times, and now it was folded double, pointed at the floor, nodding its 'head' and opening and closing its three claws in a motion that Rhodes could only describe as "grabby hands". Beneath its claws, lying on her stomach and wearing a paisley floral onesie, lay Margaret Stark – or Maggie, as her parents had nicknamed her. Her head was craned back so she could look up at the inquisitive robot, and she laughed and squealed at it as it flexed its claws and whirred at her. She was a cute kid, with wisps of brown hair, gleaming dark eyes and kicking feet. Tony stood a few feet to the side, hands on his hips as he looked down at his giggling sister like she was a machine part he couldn't comprehend.

Rhodes found himself chuckling at the laughing, dark-haired baby, the excited robot and the bewildered Tony. He stepped into the workshop, and laughed even harder when Tony looked up, saw he was caught, and immediately hustled back to his workbench covered in engine parts.

"So I see you're hanging out with your sister," Rhodes eventually noted, following Tony to the workbench and looking over his shoulder at the robot and the baby as they cooed at each other.

"Well mom and dad went to meet with the mayor and then we got in a whole thing about how I still had a nanny until two years ago – don't laugh – so they said fine, and this… is my punishment." Tony waved a screwdriver at his baby sister on the concrete floor.

"Is she going to be alright there?" Rhodes asked.

"Hm? Oh, she's supposed to have tummy-time or whatever, so I swept the workshop floor and put her in the clearest space. Just happened to be next to Dum-E, and he won't hurt her – he's not programmed to pick up anything larger than a camera, and if he pokes her in the eye she'll learn an early lesson about the dangers of artificial intelligence."

Rhodes watched the robot as it spun 360 degrees and made an extended whirring noise, causing Maggie to erupt back into peals of laughter as she wriggled her fingers. He was pretty sure that Tony was joking, and that he wouldn't have brought his sister within ten feet of the robot if there was a chance of it hurting her. Like, 90% sure.

"You gave it a name, huh?"

"Yeah, she needed one for her birth certificate."

"Ha, ha. I mean the robot. Dummy, or whatever. You're keeping it around, then?"

Tony looked up from his work on a bent gasket, and eyed his robot as it played with his sister. "Yeah, I think so. Seems useful."

A moment later, he swore loudly after spilling a can of oil across the workbench. "Anyway," he went on, "have you seen Top Gun yet?"

"I'm joining the Air Force, Tony, what do you think?"

June, 1987
Stark Mansion, Manhattan

Tony Stark graduated MIT to much fanfare at the age of seventeen, and moved back to New York to continue tinkering in Howard's workshop. Howard himself wasn't in there often, splitting his time between a project in D.C., running Stark Industries from Los Angeles, and the mansion in New York. Maria stayed in New York, raising Maggie in conjunction with an army of nannies and running Manhattan's social scene. A few weeks after moving back, Tony was arm-deep in the bonnet of a 1927 Ford when Maggie burst into the workshop in a bright purple smock, waddling as fast as her fat little legs could carry her. "To-neeee!" she cried, flashing a toothy smile as she pattered across the concrete floor.

"No," he said, holding up a screwdriver. "No, Maggot, you're not meant to be in here."

"To-neeee!" she cried again, reaching the car and making grabby hands at wiring looped out of the engine.

"No, you don't even know what those are." Tony pinched his nose and looked around helplessly for a nanny. Christ, was this how his parents felt?

"Engine!" Maggie squawked, now trying to pull herself up onto the bonnet.

"Well you're not wrong," Tony sighed, pulling her hands away and directing her out to the workshop floor. "Go play with an angle grinder or something, quit coming in here."

"Dum-E!"

Tony sighed as Dum-E heard his name, popped his head up from behind a dusty computer bank and squealed at the purple-smocked baby giggling on the workshop floor.

"Dum-E play!" He trundled over – Tony suddenly regretted making the idiot machine mobile – and leaned down to let her grab at his claws and pull his wiring.

"Hey, you, whats-your-name, Margarita – leave him alone! You break one of those wires and his IQ drops another ten points." Neither the baby nor the robot paid him any mind, so he groaned and went back to his engine.

Fifteen minutes later Jarvis burst through the door, all gangly limbs and greying hair, his perpetually-anxious expression a little deeper, and pressed a hand to his heart when he spotted Maggie trying to climb Dum-E.

"Oh good heavens, Miss Stark, thank goodness I've found you!"

At the sound of his British accent Maggie let go of Dum-E and faced the door. "Jargles!" she lifted her arms in the air and wiggled her fingers.

Tony snorted. Jarvis looked over to the car, and smiled. "Oh hello, young Master Stark, I see you're watching over your sister. She's got a terrible habit of running off and getting herself into trouble. Reminds me of your aunt Peggy. She was here recently, did you see her?" Jarvis made his way over to Maggie and picked her up, smoothing down her smock and poking her nose.

Tony shrugged. "Yeah. She somehow knew about the thing I did in Jersey-" Tony acknowledged Jarvis's 'ah' with a grimace "- and she called Maggie a 'delightful wailing nuisance', which I still haven't really wrapped my head around."

"What an excellent woman," Jarvis said fondly, then began bouncing Maggie as she started to live up to her epithet and wail. "Ah, come now Miss Stark, you'll be alright."

"Jargles!" she sobbed, gesturing at nothing in particular.

"Ugh, Jarvis, get her out, she's upsetting Dum-E."

Jarvis inspected the robot, which was inspecting a Twinkie wrapper on the ground, and raised an eyebrow. "I see. Well come on then, Miss Stark, you'll have your day in the workshop yet. For now, I see a spot of lunch in your future. Cheerio, Master Stark!"

"Bye, Jarvis," Tony mumbled, banging an intake pipe against the ground in an effort to straighten it. "Bye, Marzipan."

Once they'd left, he threw a clamp at Dum-E to stop him trying to shove the Twinkie wrapper into his own wheel mount. "Stop it, you idiot. Ugh, Dum-E, I think that's the first conversation I've had with another human in the past two weeks where they haven't compared the Maggot to whatever I was doing at that age. I'm not competing with a one-year-old."

Dum-E threw down the wrapper and ran over it, whistling.

Tony pointed the pipe at him. "Exactly."

Over the next few years, Margaret Stark followed closely in her brother's footsteps, tinkering with mechanics and computers whenever she could. She too built her own circuit board a few months after her fourth birthday. She started her first year of school in third grade, finding, as Tony had, that there wasn't really a place for the Stark kind of genius in education based on age groups.

She learned to write in English and in two programming languages at the same time. Her father set her 'projects' to further her engineering advancement, as he had with Tony, and got frustrated when they were still a little too advanced for her, or when she got bored and started playing with Dum-E instead. The only reason Howard didn't have Dum-E moved from the workshop, to Tony's horror, was that Maggie got frustrated at her lack of accurate fine motor control when it came to mechanics, and used Dum-E's help to build things. When she did complete the projects, Howard paraded her and her newest creation across the mansion and shot pointed looks at Tony. When she wasn't living up to the Stark legacy, the toddler followed her mother around asking complicated questions, and only shut up when Maria taught her how to play piano, or when they watched movies together.

Jarvis could often be heard exclaiming that he'd had enough trouble looking after one Stark, let alone three, and yet gleefully followed each Stark in their ventures, ready with a sandwich and a fire extinguisher. Tony generally avoided his sister, when he could, and attempted to ignore the many comparisons being drawn between the two of them. It wasn't a coincidence, however, that he began working for Stark Industries in earnest once Maggie started to put engine parts together. He traveled back and forth between L.A. and New York, working on weaponry projects.

November 1990
Stark Industries Headquarters, Los Angeles

"What're you doing, Tony?"

Tony groaned under his breath, and hoped that Maggie would take the blaring Van Halen as a hint and leave.

No such luck: "Tony, you seen Peter Pan?" She was four and a half years old, with a shock of dark brown hair that filled his vision as she pulled herself up onto the workbench via his chair.

"Yes, Margarine. I have seen Peter Pan. Stop moving." He winced as he maneuvered a particularly tricky bit of wiring into its housing.

"I need help working out how to fly. The movie says you need pixie dust but I know that isn't real, and there's got to be other ways-"

"Wow, you are not ready to hear about planes, kid."

"I mean single-person flight, Tony, like Peter Pan! Aren't you listening?"

"No."

"I want to fly-"

"I could throw you off the roof, you'd fly for a little while."

"Dad just said I should look into jet packs, so I'm making some models, but Jarvis said that the only jet pack he ever saw exploded, and jet packs don't have the maneuv'rability I'm thinking of, so-"

"Maggot, I'm busy. I don't want to make jet packs."

"Neither do I!"

"Then go the hell away."

There was a long pause as Tony peered through a magnifying glass at the wiring, tapping his finger to the beat of Hot For Teacher. Maggie sat on the workbench, watching him work with the precision tools, chewing her lip. She was wearing a pair of jeans and a horrific spotted shirt that her mom must have picked out. She was barefoot, but Tony decided not to point out the workshop safety violation because he was too. And kind of buzzed, but he wasn't going to bring that up with the four-year-old either.

"What're you working on?" Maggie eventually asked, picking up a sheaf of blueprints with a coffee stain on them.

Tony sighed. "It's a missile. Dad's going to be selling it to the army in a few months, I'm making improvements. Or committing crimes against engineering, depends who you ask."

Maggie leaned over the open hull of the missile and peered into it. Tony didn't even yell at her for getting her stupid head in the way because he was startled by the keen, assessing quality in her eyes.

After a long moment, she leaned back and asked: "Is it going to 'splode?"

Tony blinked. "Yeah."

She nodded. "That's pretty good. When are you going to 'splode this one?"

"Uh, probably not until the weapons demonstration." At Maggie's crestfallen look, he put down the precision tool. "But, uh, I've got a few demo models over here that could be useful for future projections."

Maggie sat up. "You're going to 'splode them!"

"We're going to 'splode them. C'mon, Magnesium."

Surprisingly, Howard didn't yell at Tony about detonating several very high-powered explosions in the demonstration bay with his four-year-old sister. He did yell at him, however, when he walked into the workshop to find Dum-E holding Maggie ten feet up in the air as an industrial fan blew the tarpaulin cape tied to her shoulders.

May 29th, 1991
Tribeca Rooftop Venue, Manhattan

"Tony, you can't be the first person to leave your own party," Rhodes hissed into his friend's ear as they moved through the businessmen, socialites, politicians and defense force members that made up the guests of the event. The rooftop was filled with the rumble of polite chatter, and very tasteful violin music.

"I'm turning twenty-one, shouldn't the party follow me wherever I go? Say, for example, to another party not hosted by my parents?" The parents in question were at opposite ends of the rooftop, entertaining their guests with flutes of champagne. Rhodes didn't fail to notice that whenever Maria looked Tony's way she would smile faintly, and when Howard looked (far less often) he would scowl. Howard had managed to convince Tony to wear a tuxedo, but Tony had finished off the look with an enormous pair of sunglasses in the shape of beer flagons.

"Ugh, there are literally no women here below my mom's age, Rhodey, what am I doing here?"

"You're being celebrated. And anyway, that's not true, what about her?" Rhodes gestured to a woman about their age sitting in the lap of an old man in a wheelchair.

"Huh," Tony said, tilting his head down so he could look over the rim of his beer-glasses. "I might have a shot there."

"Tony, no. Ew."

Half an hour later, Rhodes had gotten separated from Tony because he'd spotted a very senior Air Force General and had literally noticed nothing else until he was shaking the man's hand and politely introducing himself. He was starting to worry that Tony had bailed without him until he spotted the beer glasses through the crowd.

As he pushed through, he heard a high voice speaking animatedly: "But why did you use the Backward Euler method to solve the heat equation for the gas turbine, you said it wasn't accurate enough for the last turbine you designed!" Rhodes spotted Maggie finally, wearing a neatly pressed blue dress that already had a huge, powdery stain on it, and clutching her brother's suit jacket with a furious expression on her face.

Tony was trying to get to a waiter's tray of champagne. "Because it's immune to spurious oscillations, oh my god, go to school to learn this stuff and leave me alone, Magellan." Tony finally snagged a flute of champagne and knocked it back while simultaneously trying to free his jacket from Maggie's clutches.

"Hey, you two," Rhodes said, straightening his uniform. "Tony, I thought you left."

"I tried to, but I was apprehended by a very small, very annoying pit of stupid questions."

Maggie either did not hear or did not care about this comment, as she seemed to be contemplating the matter of spurious oscillations. After a moment of silence, Rhodes cleared his throat.

"Uh, hi, Maggie, nice to meet you again." He offered his hand to the almost-five-year-old, who blinked and then put her hand in his. She shook it with a surprisingly strong grip. Her dark eyes were startlingly intelligent for such a small kid, and Rhodes could see that she was uncomfortable about meeting an apparent stranger. Tony was being no help, so he added: "I haven't seen you since you were this small!" He estimated the size of the three-month-old Maggie with his hands.

She eyed him with very poorly concealed disdain. "Explains why I don't remember you."

"Yeah, uh, I haven't been around the mansion much, it's like trying to get into Fort Knox. I don't think your butler likes me very much."

"Jarvis is an excellent judge of character," Maggie said.

While Rhodes was just trying to work out how the hell he just got burned by a four year old, Tony finally tuned back into the conversation.

"Oh yeah. Maggot, this is my friend Rhodes. Rhodey, Maggot." Tony waved the air between them like a conductor.

Maggie squinted at Rhodes from under her dark fringe. "Y'know, roads are s'posed to be named after people, not the other way around," she eventually told him.

Rhodes blinked, and looked to Tony for help, but Tony was eyeing a pair of women close to his age at the bar.

"Um, my name's James Rhodes, actually," he eventually said, and spelled it out. "I think it's for the place, y'know, in Greece, not… roads."

"Hm," she said, still squinting at him. Her dark eyes flicked down to his uniform. "You in the army?"

Before Rhodes could correct her, she was called away by Obadiah Stane, and then Tony made his escape from the party after giving his mother a noisy kiss on the cheek in front of the Secretary of State.

"C'mon, Rhodey," Tony proclaimed as they clanged down a fire escape, "Follow the party!"

Rhodes mourned the connections he could have made at the party for a moment, then remembered that someone needed to make sure Tony didn't end up facedown in the Hudson by the end of the night. Plus, Tony had a knack for finding great parties.

Tony did end up in the Hudson by the end of the night, but that was because they'd crashed a party cruise ship and Tony had fallen in the river after trying to climb the neon flagpole. Two beautiful women pulled him out, however, so he claimed it was worth it. The next morning Rhodes pulled Tony out of a New York University sorority, and got him back to the mansion.

With Tony's very hungover directions, they evaded the Stark parents and the nosy butler, and snuck into a lesser-used kitchenette to sober up.

"Hey Tony," came a young voice from behind them as they slipped through the door of the kitchenette.

Rhodes and Tony both jumped, and spun around just as Maggie strode past them. She was dressed in stripey flannel pajamas. "Hey Rhodey," she added, heading to the fridge.

"Ugh, Magnet, what are you doing," Tony groaned, slumping toward the table and falling into a chair with his hand over his eyes.

"Getting orange juice," said Maggie, opening the fridge. She was only just tall enough to reach the juice, maneuvering it out of its shelf with her fingertips. "Thanks for leaving your party super early, Dad got mad and started making me talk to old guys."

"Give me orange juice," Tony mumbled.

"You're too old for orange juice." Maggie carefully poured herself a glass.

Rhodes closed the kitchenette door behind him, and poured two glasses of water. He passed one to Tony as he sat down.

"Hey, Rhodey?" Maggie sat at the last seat at the table with a glass of orange juice as large as her head.

"Yeah?"

"I looked up that Rhodes place. It's covered in ruins." Her eyes were serious as she looked across the table at him.

"Oh."

"But I found out that there used to be this island in Egypt-" Maggie paused to defend her orange juice from Tony's half-hearted grab – "that the Pharaoh called Antirhodos. It means basically anti – Rhodes, because the Egyptians really hated Rhodes. So they named an island to prove how much they hated it." She took a long drink of her orange juice after that, eyeballing him.

"Um," Rhodes said. He glanced to Tony for help, and was alarmed to see that the young genius was shaking – a moment later, he lifted his head and revealed that he was laughing. Tony clutched his head and laughed, all the while grabbing for the orange juice.

"Oh my god," Tony said, "Antirhodos! I'm going to use this, Rhodey, oh my god."

"Don't," Rhodes said weakly. (Unfortunately, later that week Tony placed "Antirhodos" signs above the door of his workshop, over several prominent New York City clubs, and over the aircraft hangar that Rhodes worked in.)

But on that morning, Maggie's short history lesson appeared to have brought Tony back from the dead somewhat, so he got up and poured himself a glass of orange juice. Rhodes tried to cast around for a change of subject, so the Stark daughter would stop roasting him.

"Uh, Maggie, you asked last night if I was in the army. I'm actually in the Air Force."

She put her glass down with a loud clink that made Tony wince. "You can fly?"

"Oh god," said Tony, sinking back into his seat.

The next ten minutes were filled with what felt like hundreds of questions about Rhodes's flying capabilities, his thoughts on unmanned airflight, what flying felt like, the kinds of planes he flew, and the fastest he'd ever gone in the air.

"Well maybe I ought to take you up some time," he eventually offered, thrown off by her sudden change from thinly veiled mistrust to avid admiration.

Her eyes were wide. "Flying? You'd let me fly a plane?"

"Well I'd fly the plane, but you could come with-"

"Jeez, Rhodey," Tony cut in, "asking a guy's sister out right in front of him, that's cold."

This led to at least twenty minutes of Rhodey-roasting by Tony and Maggie, the two of them often using language that went way over his head.

That morning was the one that James Rhodes realized the Stark siblings were going to be a force to be reckoned with.

I'm Australian, but attempting to write with American spelling & formatting to keep in line with canon (send my apologies to the Queen). So please excuse any slip-ups!