Written for this prompt: When Sam's away...the shadows will play. Dean dreams, breathes and hides in the dark - and the dark hides within him.

The Space Within

Tonight is going to be a bad one-in the weeks since his brother's been back from hell Sam has learned to recognize the signs. Dean's not the same man he was six months ago, not even close. He's quieter, more contained, and somehow less than he was before his trip downstairs. The nightmares don't come every night but Sam has become able to predict when they will. Dean folds in on himself, becomes even dimmer and Sam dies inside a little more every time he's faced with the loss of the whirlwind of light and life that used to be his brother.

Dean's got half a bottle of Jack polished off before he passes out around eleven. The bad nights always start with alcohol and go downhill from there. Sam stretches out, fully clothed, on his bed to try and get some rest. Ruby called earlier with a report of at least one demon in the area and once she locates it she'll be calling back, then coming by to pick Sam up. He hopes she calls soon, before Dean starts to dream. Dean swears he has no memories of hell, but from the way he cries and moans and screams in his sleep Sam is sure that his subconscious, at least, remembers. The nightmares are loud, messy, and excruciating for Sam to listen to, but he's learned that it's better to let Dean have them and sink back into dreamless sleep without waking, than it is to pull him out of one. Sam's woken Dean mid-scream a couple of times and Dean's reactions made him swear to himself to never do it again.

Dean is disoriented when he wakes, flailing and begging until he realizes where he is, then he always pushes Sam away and runs to the bathroom to vomit. Sam never gets a response when he asks if Dean's okay, though he admits to himself it's a stupid, reflexive question. Only an idiot couldn't see that Dean is miles from okay and Sam's not an idiot. Dean doesn't come out of the bathroom until he's got himself locked down tight and anything Sam asks gets a response of I'm fine, and a glare that discourages any more conversation. Not that Sam lets that stop him, but he gets nothing further from his more Sam asks, the more withdrawn Dean becomes, and he starts drinking heavily again a few minutes after Sam gives up and goes back to bed. Dean huddles against the wall at the head of his bed and stares straight ahead as he takes long pulls from his bottle. When he thinks enough time has passed that Sam has fallen asleep again, he'll cast desperate, panicked looks his brother's way, terrified that he's screamed his closely guarded secrets to the world. He will sit like that all night, jerking himself to wakefulness whenever he feels himself drowsing and the next day he's exhausted, hung over, and humiliated that Sam witnessed his weakness. When Sam lets the nightmares take their course, Dean will wake the next morning, still exhausted but without the effects of all the extra alcohol and of not being strong and silent in front of his little brother.

Sam's phone vibrates as Dean starts to writhe and moan and he sighs in relief as he reads Ruby's text. He gets up, telling himself that it's okay to leave Dean like this- that his brother will never even know that he's gone, as he goes outside to wait for his ride.

Dean's on the rack - being burned, flayed, cut into pieces, pulled apart and then he's whole so a whole new round of torment can begin. The images pound his brain, remembered pain and terror forced out of his lungs in hoarse screams. The torture goes on and on and the screams become weaker and weaker until they finally stop. Dean has stepped off the rack now. Accepted Alastair's offer and become an artist in his own right. His mind replays some of his most brutal palates, painted in vibrant reds and blacks and from deep within the recesses of Dean's soul a darkness creeps to the surface. Ebony tendrils curl beneath his skin in an intricate pattern that carefully avoids both his protection tattoo and Castiel's handprint. The screams of his victims play like a symphony in his head and the sound that comes from his mouth is a dark laughter.

Eyes open as it sits Dean's body up and the usual dull, shuttered gaze is replaced by glittering emerald malice. The combination of nightmares and booze force Dean's essence to the background and allow it to come out and play, with Sam's exit as its cue to emerge. It can't hide what it is from strangers; Dean's precious baby brother would recognize its wrongness in an instant. It laces up Dean's boots, sliding a small knife into one, then attaches a much larger knife in its sheath to his belt. It briefly considers tucking a gun into Dean's waistband but decides against it. It wants the fun it has tonight to be up close and personal. It grabs Dean's jacket and digs the keys to the Impala out of the pocket. As the Impala rumbles out of the parking lot, guests in the surrounding rooms slip from violent nightmares into sound, peaceful sleep.

Checking out what Sam is up to is its first order of business and it takes a moment to concentrate on locating him. Their shared blood sings to it, creates a pull that it could follow halfway around the world, Azazel's demonic upgrades an unnecessary, but intoxicating addition. It closes its eyes and inhales deeply, catching Sam's scent faintly across the miles that separate them, listens closely to hear the faint pulse of the blood in his veins. All its senses are attuned to Sam, and it only lacks the sight of him to make everything complete. Its smile flashes in the darkness as it speeds down the pathway to its ultimate victory.

It finds them in a warehouse outside the city limits, the place practically glowing from the brightness of Sam's aura. It parks the car a few blocks away, the rumble of its engine the only thing that could alert them to its presence. It can feel Ruby as well as Sam, her blood dark and stinking like carrion, but the designs it traced on Dean before taking him out prevent anything-demon, angel or human from detecting its presence if it doesn't wish it. It watches through a window as Sam raises a hand, face tight with concentration and pulls a demon from the body it's possessing. It can practically see the power, dark and writhing through Sam's bloodstream, flowing out of him like a wave. It closes its eyes and inhales its blood brother's overflow of power, clenching its jaw against the howl of triumph that wants to spring from its lips.

When it brings its attention back to Sam, Ruby is at his side, pressing up against him with a smile. She pushes against Sam's chest, backing him up until he falls backward to sit on a packing crate, then crawls onto his lap. The smile drops from its face and it's amazed she can't feel its malevolent stare even through its wards. It doesn't care that Sam's fucking her-he's a big boy, he can do what he wants-it's what comes after that makes it want to put her back in hell. Eventually she'll make a cut, feed Sam her weak, inferior, non-Winchester blood. It hates the fact that Ruby is doing the job it so desperately wants to be doing; leading Sam down the path to Lilith. It knows Ruby has to be the one. Sam would never accept this from it. Not yet.

The smile comes back to its lips as it pictures Sam's face when he finally gets where he needs to be. Finds out what killing Lilith means-how Ruby has played him. Sam's in for a real surprise. The smile widens as he thinks about the surprise Ruby's going to get. Ruby's got plans, knows she'll be rewarded when Lucifer rises. It's going to kill her before that happens. Not that it's going to let it happen. It knows how things are supposed to go when Sam meets Lilith. In hell it had been busy, first being born, then becoming what it is today, but, just like with Dean, hell had underestimated it. It had kept its ears open and heard things it wasn't supposed to hear. When that stinking angel had come for Dean it had clung for dear life, hiding deep within when Dean's body was resurrected.

Now it's got plans of its own. It wants revenge on Lilith just as much as Sam does, but there are better ways than killing her and it spent years learning all of them. Learning how to make her punishment last an eternity. After it's killed Ruby and trapped Lilith where only itself and Sam can get to her, it will free itself, take over and give Dean the rest he so desperately craves, so richly deserves. It will take its knife to Dean's arm and finally feed Sam their blood and drink Sam's in return. The power each other's blood will give them. The power of a bloodline that's been carefully selected for millennia, reaching its culmination in them. A bloodline that the powers that be in hell tampered with; augmented in their arrogance. Well, they'd learn their mistake when it prevents Lucifer from rising. When heaven and hell are denied the apocalypse they want so badly. When the Winchester brothers come into their full powers and shake the world.

It needed to leave, now, before its anger and frustration at having to wait totally overtake it and it gives itself away. It grips the knife at its belt tightly and grins as it leaves to find a pretty young thing to relax with. It will be hours before Sam is done and if it leaves now it can take it's time, do the job right. When it reaches the Impala, it runs a hand across her hood. It doesn't have the same feelings for the car that Dean has but it can appreciate what a perfect vehicle she is for it; pitch black and invisible in the dark-just like it is. Concentrating briefly, it picks up an image of a teenage girl asleep in her bedroom a mile or so away. She's dreaming-pleasant thoughts of her boyfriend-and it guns the car forward, anxious to join her.

It gets back to the motel just before dawn. Sam's not with Ruby anymore, but he's not in the room either. Probably getting food so he can pretend to just have been out getting breakfast. It snorts softly to itself, unable to believe that Sam really thinks his brother is that stupid. It carefully puts the knives, boots and jacket back where it found them before it puts Dean back to bed. The markings fade from his skin, sinking back to their hiding place deep inside as Dean sinks into sleep. A few minutes later his eyes open, dull and tired with dark circles beneath them. He looks at the other bed, empty and unused, as he sits up and tries to be angry at Sam but the most he can manage is weary resignation. He closes his eyes and buries his head in his hands as he searches for something that he's not even aware he still has. It feels Dean reaching, and, as it does every morning it releases a tiny tendril of its power, giving Dean the strength he needs to face another day.