They know from the start that it's not going to be his. There was the whole harpies-in-Syria thing at the time of conception, which was just no, never again no—so there's that. It's not Percy, because he was busy with Clarisse in a tiny little village on the other side of the world while his wife finalized the plans for rebuilding Olympus in Manhattan and apparently had some unsafe celebration sex with their lover. So no, it's not technically Percy's kid.
But he's there for the birth, Nico at his side chewing nervously on his lower lip and playing with the shadows in the corner of the room until Annabeth shrieks at him to just stop, because the change in lighting every two seconds is making her woozy. They're both there for the doctor cooing quietly to breathe, just breathe, sweetheart, even as Annabeth tries to burn her alive with the force of her glare alone. They're there when the doctor turns to both of them, slightly confused, and asks whether or not they want to cut the umbilical cord, which again—just no.
And they're both there when the baby wails for the first time after the doctor has cleaned the gunk out of it's mouth, giving it a cursory wipe-down like a kid coated in blood and afterbirth is perfectly normal. Which, well, for her it probably is, but Nico looks ever so slightly green and Percy's just hoping that Annabeth hadn't seen either of their faces at that first glimpse of their child.
They're there when Annabeth breathes shakily afterwards, Nico's hands stroking through her sweaty hair and Percy just staring at this kid who isn't his, but theirs. She looks like Nico, dark hair, dark eyes, and skin like Nico's had been before he'd spent too much time in the Underworld. She's got Annabeth's chin and when she grins for the first time, the resemblance is there, clearly for all to see.
Percy takes one look at the child and that's all it takes for him to fall in love. Because this isn't about blood, and it never has been. Their daughter might not look like him as she grows up, but she's his as much as she's Annabeth's and Nico's. And that's what really counts.
The first time he sees Nico, the synthetic is playing cards by himself in a corner of a darkened room. There are higher ranking androids all around him, older and more experienced—far more suitable to be the bodyguard of a child of Poseidon, but that's not what Percy wants. He wants this kid, playing in a corner all by himself with an aviator's jacket wrapped around his small frame like it's going to swallow him up. So Percy points to Nico and they take him home.
Other things will come later—Nico teaching him how to play cards, and Nico explaining that his model controls the shadows—that they were specifically designed to be assassins rather than bodyguards.
Other things are still to come, like the slick feel of Nico's mouth on his, and his hand clutched tight to Percy's as he's guiding him away from harm.
For now, they take Nico home. Their story has yet to start.
03. Gods and Demons and Angels, oh my!
It isn't that Nico's a masochist, he just doesn't know how to find that off button that people have when they realize that they're about to do something stupid. A son of one of the old gods and an angel—not the best of ideas. It doesn't help that they've got a demon on their side as well.
Her name is Annabeth, and she tells him that the form she wears—blonde and tall and strong-willed—is the closest she's ever come to finding a body that looks like she did when she was alive, when she was a priestess of Athena in the good old days, back before the humans forgot the old gods and latched onto a new one. Christianity is complicated, she tells him, and Percy laughs at her, green eyes bright as his wings hold back a hoard of monsters intent on crunching Nico's bones between their teeth.
Faith is complicated, he corrects—whirling to dispatch a harpy that had edged around the side of his wings. The blade that he wields glows blue in the darkness, holy fire that makes Nico think of the River Styx, and the spray of the harpy's blood spatters across his face. Annabeth tuts at him, whipping a handkerchief from her pocket to wipe the blood away. She grins and licks a stray drop away from the corner of his lips. Her eyes are black as coals, and when she darts past Percy's wings and into the fray, it occurs to Nico that he should be helping.
Percy looks at him, eyebrows raised as gore coats the backs of his wings, Annabeth's laughter echoing around the clearing. Nico turns his eyes skyward, and wonders how bad of an idea this is. Not the fighting, but the way Percy leans down to touch his lips to the place Annabeth's tongue had been moments ago.
The earth rumbles and an army of skeletons shake themselves free of the dirt.
He'll worry about his fucked up love life later.
See, the thing is, you're the captain of this ship. Her name's Poseidon, because when you've been spontaneously transported back into the past (like way past, like toilet's haven't even been invented yet and the best way to get to America takes five months on a ship, and oh yeah, you might get scurvy) you apparently name your ship after your dad, even if that parental figure doesn't know you exist yet, because hey, hundreds of years before he ever had that particular tryst.
Oh yeah, and your girlfriend has been turned into a very cross mermaid and your boyfriend briefly considered being your first mate before he fucked off to be a pirate.
Which brings everything up to date, where your pirate boyfriend has you tied to the main mast, a sword at your throat as Annabeth shouts obscenities up at the both of you from the water, and your crew has already jumped ship because apparently drowning was better than being involved in this freak show even a little bit longer.
Nico grins down at you, skin tanned dark and eyes like the inside of an oil slick, and tells you, "I think I found a way home."
You frown at him. "Couldn't you just have told me that before you took over my ship and terrorized my crew?"
Nico just grins. "Pirate."
Somewhere below you, Annabeth shouts up, "Can we please go home now?"
You all go home. It's just another story to tell.
05. …In SPACE!!
He isn't quite a star child, not really. His mother once tells him that his eyes shine like the stars—that they have a glimmer of his father in them, but Nico can't see it. He can walk the paths of the galaxy, knows them like the back of his hand. Shadows bloom at his touch, and the stars rejoice at his presence—but it's not the same. He's a freak, a mutt, half human, half star, and he hates it. He will never take a form like his brothers and sisters—will never shoot across the sky with a comet's tail behind him. For all that he is a shooting star, he doesn't feel like one.
And then he meets Percy—Percy, who is a true child of starlight. Who gleams so bright that sometimes, Nico fears he may blind him. But Percy isn't like the others. He treats Nico as one of his own, and when he takes Nico's hand, they blaze across the night sky.
06. Born Another Gender
Medea has always been a little strange. She likes blue colored foods and has been able to hold her breath underwater for upwards of ten minutes since she was eight years old. The fact that she's a daughter of Poseidon is just the topper of the whole weirdness cake.
The Annabeth thing was never really weird though. She doesn't care what anyone says—the fact that she likes girls has never been something that makes her a lesser person. She's still Medea, daughter of one of the Big Three, the girl who held the world on her shoulders, if only for a moment.
The weird thing is Nico and how he's a boy. Rather, he's a boy licking his way down her collarbone, inky black hair in his eyes and a smirk on his lips.
Boys have never appealed to her before. She's always looked at them as friends, allies even—and she can't remember a single time in her life that she's looked at one and wanted to climb him like a tree. It isn't like Annabeth, with her cool hands dipping below the waistband of Medea's panties—and it definitely isn't like Rachel, whose legs have become an increasingly problematic distraction. Even Thalia was gorgeous enough, powerful enough, that Medea had felt the gravitational pull of her, tugging Medea closer and closer until it was all she could do to not embarrass herself. She's pretty sure that if she'd gotten down on her knees and asked Thalia, please, please, pretty please, won't you let me eat you out just once? that she would have been skewered before she could draw Riptide.
It's always been girls, until Nico.
Rachel tells her that there will always be at least one person who makes you rethink your sexuality, even if for only a moment. She'd laughed at Medea, nudged her between the ribs, and said, "hell, boys are divine, but if you'd removed yourself from Annabeth's ass for even a second, I would have been all over you."
So there's that. There's the fact that Medea and Annabeth had an amiable breakup three months ago, and that other than a random girl in Corpus Cristi, Medea hasn't wanted to look at anyone else since.
And then there's Nico, who Medea does want to climb like a tree, boobs or no boobs. So she does. She makes her move, and when the result is sex of truly epic proportions, she pushes her doubts about whether or not this means she likes cock now into the furthest corner of her mind and just goes with it. There's always someone. Nico's her someone.
School is harder to get back into once you've saved the world. School is even harder to get back into when your girlfriend is going to school two states away and Nico di Angelo is suddenly living in your space, sleeping in the bathtub and pinching your pillows and leftovers.
After saving the world, this should be small time, Percy thinks, watching Nico brush his teeth two feet away from him. His mouth is foamy blue—Percy's toothpaste and the green toothbrush that's been in the bathroom for four years, just waiting for a guest to come over and use it. Nico's gargling by the time Percy's mom yells up the stairs that the bus will be arriving in ten minutes and 'Percy Jackson, you better get your ass in gear, because I'm not driving you.'
Nico gives him a grin, still gargling, and spits.
Two weeks later Percy's mom will find Nico and insist on getting him into school. Percy's pretty sure the whole thing would have been worse if his mom wasn't aware of the whole demigod situation, but it's still weird when she calls Nico down for dinner each night. Weirder still is when she shoos them both onto the bus three days later, thrusting a fully stocked backpack into Nico's arms, and telling them to have a good day at school.
School's fine. Nico eats lunch with him and talks about how much the freshmen suck, and how history class really is hell when you've been stuck in a casino for the last forty years. They go home together, riding the bus like normal kids and talking about flying horses on their way back.
When they get back, there's a blow up mattress on Percy's floor, and a post-it stuck to the tub that says 'NOT FOR SLEEPING' in large blocky letters.
Nico moves out of the bathtub, and Percy tries not to step on him in the mornings.
Yeah, definitely weird.
The world doesn't end with zombies, much to everyone's surprise. It ends with a lover's quarrel—armies of skeletons, quaking earth, and churning seas. A lover's quarrel that would have turned out okay for the rest of the world if the quarrel in question wasn't between a child of Hades and a child of Poseidon.
The world ends, and Nico's eyes cut him to the core.
09. Urban Fantasy
"Vampires suck," Percy says, rolling his eyes. Nico's response is muffled against Percy's skin, his fangs still buried in Percy's neck.
"That's kind of the point," he says when he pulls away, blood against his lips.
10. Crossover - Firefly fusion.
Nico's kind of crazy. Hell, everyone knows that. It's like saying that the sky is blue or that the grass is green. He's crazy as all hell, batshit in the belfry and all that. But the thing is, he's also smart as all hell. Percy doesn't know what that crazy ass school had done to him before his older sister broke him out, but whatever it did to him didn't change the fact that he's the smartest person on this ship. Smarter than Rachel, who could take their engine apart and put it back together even better in less than an hour. Smarter than his sister, who used to be one of the best surgeons in the whole of the verse. He can fly the ship better than Leo, and he's somehow more of a badass then Annabeth, which just... wasn't done.
So yeah, Nico's a special little snowflake and the Alliance wants him back for his potential as a weapon, but nothing's gonna make Percy let him go now that he's got him. Nico likes Serenity, and in his calmest moments, he'll tell Percy so, stroking the sides of the ship and cooing gentle little words that sound strange coming from Nico's mouth.
There's a moment there, when they're somewhere amongst the outer planets, just drifting, that Nico smiles.
Percy's room is no larger than the rest of the crews. It doesn't matter that he's captain of the ship—Serenity is an equal opportunity kind of broad, and he likes it that way. So when Nico slides down the ladder and into his room, there's not many places for Percy to go. At first, he kind of just hunches down, tucking himself back against the wall as Nico stares at him—but then, Nico's backing him towards the bed, where he drops like a pile of rocks. Once he's there, staring up at Nico, he thinks that this is the moment where he should have something to say about this. Something about Nico's age, or that Bianca would probably disembowel him slowly if Percy even thought about touching her little brother, which—well, all right, he's doing that now. It's hard not to think about it when Nico's standing between Percy's spread thighs, a small smirk on his mouth as he moves even closer—until he's straddling Percy's lap. Percy's ready to say something when Nico smiles, something real and tangible, and presses his mouth to Percy's.
It's just a touch. Just their mouths pressed together, sharing the same air, the same warmth. Until—well, until it's not just a touch, because Percy makes a noise in the back of his throat and deepens it, threading his fingers into Nico's dark hair and tugging—just enough that he can get him closer, lick into his mouth and taste him.
When he pulls away, the guilt sets in. Nico's mouth is red, his eyes glazed with want, and you don't just make out with a crazy seventeen year old with a homicidal, slightly too protective sister somewhere on this ship.
Something must show in his eyes, because Nico presses forward, rocking their hips together so sharply that Percy can't help the little gasp that makes it's way out of his mouth. Nico presses a finger against Percy's lips.
"No power in the verse can stop me from having this now that I know you want it, Percy Jackson," he whispers, punctuating the statement with a sharp bite to Percy's collarbone. He kisses Percy again, slow and gentle, and uses the moment of distraction to slip a hand down Percy's trousers.