Title: Only by Half
Author: Spinny Roses
Pairing: Sam/Dean
Fandom: Supernatural
Rating: R
Warnings: Incest (Dean/Sam), evil!Sam, random het
Spoilers: Up to "Provenance"
Disclaimer: Don't own
Summary: Dean wonders if psychic powers are hereditary. If they are, why Sam developed them and not him, not John.


Dean wonders if psychic powers are hereditary. If they are, why Sam developed them and not him, not John.

He usually thinks about this while Sam is suffering from a precognitive nightmare, leading them to their new job.

They decide to spend winter up north. Well, it's less deciding than hunting what appears to be a gryphon across the entire northern states. Sam wakes in the middle of the night, always, Jessica's name on his lips while messily entangled with his brother.

May finds them in Oklahoma, Dean flirting with a girl with long brown hair, big hazel eyes, and perky breasts. Sam ignores him, ignores her, in favor of signs of a soul-sucking demon.

The final victim finds himself on his back, hands gripped onto dusky skin as he thrust into her, the scent of her rushing into him and teasing his memory. Sam kicks open the door as Dean opens his eyes, the succubus still riding him. She's stronger than she has any right to be. Sam nearly splits his head open while Dean almost has to mourn the loss of his dick.

One incantation later, she's cursing them on her way back to hell. Spitting half-truths and lies. You smell of your brother, she jeers, of lust and sex.

Sam spits out the final lines, doing the equivalent of slamming the door on her ass on the way out.

Texas in the summer finds them driving down to Corpus Christi, wondering if something is in the Gulf of Mexico. They stop in San Antonio for the night, and Sam finds a sassy redhead in a nearby library with a pentagram around her neck and huge breasts.

Texas in the summer is when they find their first half-demon, the pentagram bouncing above a magically augmented body as she telekinetically throws the brothers onto an altar.

Dean can't breathe, can't move, can't even think past the induced terror.

Sam grabs her athame and slits her throat, spilling red blood over white concrete.

They leave San Antonio, heading towards the Gulf, not asking why Sam wasn't affected.

Random time, random city, and the brothers are low on holy water. Sam goes to nick some from the local church, and comes back with a light burn on one hand.

He claims he hit it on a door.

Dean doesn't ask.

Dean finally convinces Sam to go to Nevada. Not Vegas, not to gamble, but a hint of Indian curses flaring up again. The motel only has one bed.

When Sam dreams that night, Jess is under him, offering her body, her breasts, her pussy to him. Above him, inside him, is Dean, fucking his little brother, and by proxy, Jess.

When he wakes up, he doesn't know who's name to call.

Dean handles all holy objects now. It's not that it hurts Sam, or at least not so it'd cripple him. A slight burn, equal to a light sunburn.

Sam can move objects at will now. But he misses being able to hold the first thing his father gave him, a small cross.

They manage to spend the next winter in Florida. It's still chilly, but there's no snow.

This motel has two beds. Both brothers go to sleep in their own beds, ready to face their nightmares.

When Dean wakes up, he's about to kiss his brother, his hand creeping into Sam's boxers.

Sam wakes up alone, in Dean's bed.

In spring, their father meets up with them as they go on a hunt together. Neither Sam nor Dean let him know what's going on while John rattles on about what kind of monster it is.

Sam drops the bottle of holy water on himself while they're fighting, yelping in pain as it burns him.

Neither Dean nor Sam could explain it to their father as he stood there over massacred bodies, looking at Sam with distrust and fear.

Dean heals at a normal speed. Sam has to clean all of his wounds, bandage them, and drug his brother so he actually rests.

By the time Dean finishes washing the blood away from Sam's wounds, they've already scabbed over, no longer bleeding. They're well on their way to becoming a distant memory, not even scars.

The only thing Dean can do is hug his brother from behind, trying not to freak out at the changes in his baby brother. Trying not to cry as Sam turns his head, innocently wondering what's wrong.

They end up traveling through Kansas. Missouri calls them, letting them know that they aren't leaving without visiting her first. Dean laughs, trying to bluff the psychic, but she doesn't believe a single word.

Sam finds out he can't enter her house.

She has a horseshoe over her doorway.

Mary was sick right around the time Sam would have been conceived. Doctors said it was the flu, that she wasn't even supposed to live.

Dean puts down the medical records, not wanting to believe.

The first night they kiss, Dean had been hacked to nearly an inch of his life. Sam had been hugging his big brother tightly, scared he would suddenly disappear or die, when Dean turned and kissed him.

What are you doing, Sam whispers, not pulling away. We're brothers.

It's okay, Dean tries to soothe him. Dad's not your dad. We're not brothers.

Sam leaves, doesn't stumble back until early the next morning.

Sam finds the same medical records.

The hospital implodes, killing hundreds.

Only Sam walks out alive, unscathed, eyes glazed over.

He doesn't blink all the way back to the motel.

Dean hears about the hospital, not from Sam. Local news, horrible tragedy.

Sam turns off the TV and kisses Dean.

They meet their second half-demon in Ohio. This one was less subtle than the one in San Antonio, far more powerful. He nearly sets both the brothers aflame when Sam tosses him against a wall with his mind alone. The half-demon falls to the ground, stunned and bleeding.

Dean makes a crack about family reunions.

He nearly dies when Sam tosses him as well.

When Dean wakes up, Sam's in his bed again.

Instead of feeling guilt, disgust, or horny, all Dean feels is fear as Sam opens his eyes.

You aren't my brother, he whispers against Sam's lips.

You said it yourself, the thing in Sam's body whispers back. We're not brothers.