Dark Percy Jackson x Mortal! Reader
Look, you didn't ask for a best friend whose dad is the god of the sea. You just wanted someone to share blue Jolly Ranchers with during Algebra II.
Being friends with Percy Jackson comes with a lot of hazards. Exploding toilets? Check. Gym teachers turning into monsters you cannot see? Standard Tuesday. But the biggest hazard, the one nobody warned you, is the summer.
Specifically, the part where he vanishes to Camp Half-Blood, and you stay in the mortal world.
For Percy, camp is supposed to be a safe haven. But this summer, the monsters aren't outside the borders; they’re in his head. Every time he tries to sleep in Cabin Three, listening to the fountain drip, his ADHD brain doesn't focus on quests or prophecies.
And more specifically, on the guys who get to sit next to you in the cafeteria while he’s off fighting harpies.
He tries to Iris Message you, but the connection is always misty. Once, he saw a guy’s arm draped over the back of your chair. Just a friendly gesture, right? Not to Percy.
To Percy, that arm looked like a hydra head that needed lopping off. He spent the rest of the summer slicing training dummies in half with a little too much enthusiasm, imagining they were wearing varsity jackets.
By the time August rolls around and he comes back to the city, the jealousy has crusted over his heart like barnacles on a hull.
The reunion is supposed to be sweet. You guys plan a trip to the beach, Montauk, obviously. It's his turf.
He wants to show off a little, maybe walk on water, maybe just hold your hand without worrying about a hellhound jumping him.
Kyle is perfectly nice. He’s in your biology class. He has floppy hair and a laugh that sounds like a seal barking, and he brought a Frisbee. He is entirely, tragically mortal.
"I didn't know we were bringing guests," Percy says when he sees him.
His voice is casual, that easy-going tone he uses when he’s bluffing a god, but his eyes are stormy. Sea-green, darkening to a violent, deep-ocean gray.
"Kyle just wanted to tag along," you say, smiling, oblivious to the fact that the air pressure around you just dropped ten degrees. "Is that cool?"
Percy forces a crooked grin. It doesn't reach his eyes. "Yeah. Totally cool."
The drive is excruciating. Kyle talks about lacrosse. Kyle talks about his dad’s boat. Percy grips the steering wheel so hard the leather creaks, listening to the way you laugh at Kyle’s terrible jokes. In Percy's mind, he's connecting dots that don't exist.
She likes him. She forgot about me. I saved Olympus, and I'm losing her to a guy who wears Axe body spray.
When you get to the beach, the ocean greets Percy like an old friend. The waves get choppy, slamming against the sand with a rhythm that matches his heartbeat.
"Let's get in!" Kyle yells, peeling off his shirt and sprinting for the surf.
You follow him, wading in up to your waist.
The water is cold, waking you up, salty and sharp. Percy stands back for a second, watching. He watches Kyle splash you. As he watches you shriek and splash back. He watches Kyle’s hand linger on your shoulder to steady himself against a wave.
Percy walks into the water. He doesn't shiver. The ocean doesn't make him cold; it energizes him. He feels the currents tugging at his ankles, waiting for a command. Being the Son of Poseidon isn't just about talking to horses or breathing underwater.
And right now, he feels like he’s losing control of everything, except the sea.
"Hey, Jackson!" Kyle calls out, treading water out past the break. "Bet you can't swim out this far!"
Percy smirks. It’s a dark, sad little look. "You would be surprised what I can do."
Under the surface, it’s silent. Percy opens his eyes. The salt doesn't sting. He looks at Kyle’s legs kicking aimlessly above him. He feels a pang of guilt a small, mortal part of him that says this is wrong.
But then he remembers the way Kyle looked at you, and remembers the long, lonely nights at camp wondering if you were moving on.
The jealousy roars louder than his conscience.
The water obeys instantly. It doesn't look like magic from the surface. It just looks like a freak current. A riptide.
Around Kyle, the water hardens. It shifts from fluid to a vice. You’re only ten feet away, laughing as you wipe water from your eyes, waiting for Percy to pop up. You don't see the way Kyle's expression shifts from joy to confusion, then to sheer panic.
He tries to swim up, but the ocean grabs his ankles. It’s not a wave crashing down; it’s the depths reaching up.
The water fills Kyle's mouth before he can scream. It drags him down, heavy and relentless.
Percy stays under, watching. He ensures the current pushes Kyle deep, tumbling him along the sandy bottom, far away from you.
Far away from anyone. The ocean is vast, and it keeps secrets better than anyone.
When Percy finally breaks the surface, he’s right next to you. His hair is wet and messy, his eyes bright and innocent.
"Where's Kyle?" you ask, looking around. The water is calm now. Suspiciously calm. "He was just here."
Percy looks around, feigning confusion perfectly. "I don't know. Maybe he went back to shore? Or maybe he swam out further?"
"Kyle!" you yell, spinning in the water. Panic starts to set in. "Kyle!"
Percy puts a hand on your arm. His grip is firm, grounding. "Hey, hey. Don't worry. I'm here."
He pulls you closer, wrapping an arm around you to keep you steady against the gentle bob of the waves.
You're trembling, scanning the horizon for a friend who is already miles deep and miles away, carried off by a current that answered to one master.
"I’m sure he’s fine," Percy lies, his voice smooth like velvet. He rests his chin on top of your head, looking out at the endless blue.
The competition is gone. The doubt is drowned.
"It's just you and me," he whispers into your hair, holding you tight as the tide rolls in. "Just you and me."
Hours later, the moon is high and the house is quiet.
You are asleep inside the rented beach house, exhausted from hours of crying and talking to the Coast Guard.
While Percy is sitting on the porch railing, his legs dangling over the edge, staring at the dark horizon. He’s drinking a blue cherry Gatorade, looking for all the world like a guy who’s just bummed out about a tragic accident, not a guy who just orchestrated one.
The air smells like rain and ozone. Suddenly, the scent shifts. It smells like a sea breeze mixed with Old Spice and suntan lotion.
Percy doesn't even look up. "Hey, Dad."
Poseidon leans against the porch support beam. He’s dressed in his usual vacationing in Florida attire, khaki cargo shorts, leather sandals, and a Tommy Bahama shirt with parrots on it that seem to be actually moving. He looks relaxed, but his eyes, those same green eyes Percy has, are narrowed.
"Rough day at the beach," Poseidon says. His voice is deep, like the rumble of a wave hitting a cliff.
Percy swirls the Gatorade in the bottle. "Yeah. Current was strong. You know how it is."
"I do," Poseidon says. "I also know the difference between a natural riptide and a hydro-kinetic execution."
Percy finally looks at him. There’s no fear in his face. Usually, Percy gets nervous around the gods, worried about smiting or turning into a dolphin. But tonight, he looks hollowed out and hardened.
"He was touching her, Dad," Percy says. It’s not a whine; it’s a statement of fact. "He was loud, annoying, and he thought he had a chance."
"So you drowned him," Poseidon muses, stroking his beard. He doesn't sound angry. He sounds like he's reviewing a batting average.
"I removed an obstacle," Percy corrects. He sets the bottle down.
"I spend all year fighting giants and Titans. I hold up the sky. I save the world. I come back, and some mortal with a Frisbee thinks he can just take my place?" Percy shakes his head. "I didn't survive Tartarus to lose her to Kyle."
Percy waits for the lecture, waits for Poseidon to tell him that heroes don't kill mortals, that he's crossed a line, and that Zeus is going to have a field day with this.
Instead, Poseidon chuckles. It's a dry, salty sound.
"You really are my son," the god says, a strange sort of pride in his voice. He walks over and puts a heavy hand on Percy’s shoulder. "I was worried you were taking too much after your mother. Too soft. Too forgiving."
Percy blinks, surprised. "You're... not mad?"
"Mad?" Poseidon looks out at the ocean, watching the moonlight dance on the black water. "Percy, look at me. Do you know how many sailors I have dragged to the bottom just because they didn't pour enough wine overboard? Do you know what I did to Odysseus just because he blinded my son? I made him wander for ten years."
Poseidon looks back at Percy, his eyes twinkling with ancient, chaotic energy.
"We are the sea, Percy," he says softly. "The sea is beautiful, yes. But it is also jealous. It is possessive. It takes what it wants, and it does not give it back."
He squeezes Percy’s shoulder. "You saw something that belonged to you, and you made sure it stayed yours. I can’t exactly fault you for acting according to your nature."
Percy breathes out, a tension he didn't know he was holding releasing from his chest. "So, I'm good?"
"You're fine," Poseidon assures him. "The mortals will call it a tragedy, the police will find nothing and the ocean keeps its secrets." He pauses, fading slightly into mist, ready to return to Atlantis.
"Just...maybe keep the body count low, son. It makes the paperwork annoying."
"Thanks, Dad," Percy says.
"Don't mention it," Poseidon says, his form dissolving into sea spray. "And Percy? She's a catch. Don’t let anyone else cast a line."
"I won't," Percy whispers to the empty porch. He looks back toward the window where you’re sleeping. "Never again."
