Brother my Brother

Summary: Dean knows what it means when his nightmares change. Set Season 5 or later.

Dean still has nightmares of Hell. Memories, dreams. But though he'll never tell Sam, his worst nightmares aren't his actual memories.

They're his dreams of when Alistair is preparing to throw him on the rack, and Sam appears and takes his place. Dreams where his brother endures the things he went through.

Or worse. Sometimes he dreams that Sam is on the rack, and he's the one wielding the blade that cuts into his brother. When he has those nightmares, he wakes crying in the dark, too anguished and horrified to even scream, and he doesn't go back to sleep for a couple days, and then only after he drinks himself into oblivion.

Time lessens the frequency of the nightmares, but they never quite go away. He takes to drinking after really stressful days, hoping to stave them off. Sometimes it works, sometimes it doesn't.

They never talk about it, but he thinks Sam understands.

Then one night, he's in Hell, the familiar dread coiling in his gut. Waiting to see which flavor of nightmare it's going to be. Then someone touches his shoulder, too light and gentle for a demon, and he turns.

It's Castiel. Eyes dark and solemn. Head tilted in that familiar questioning look. Serene and strong. His voice deep and calm and as steady as the earth. "Don't be afraid. You are safe, Dean. I'm here to save you. "

For a moment, he thinks he's remembering his rescue from hell, when Castiel raised him from perdition. But then he realizes...something is wrong. He's not getting that sense of power he associates with Castiel at full strength. And he knows, somehow, that it's not going to be that simple. Dread fills him.

Then Castiel walks past him, toward the racks, and he knows with sudden horrible certainty, what is about to happen.

He watches, helpless and frozen, as the terrible chains pierce the angel. Pull him spread-eagled, hanging from his wrists.

Castiel, not Sam, is taking his place on the rack this time. Castiel whose expression goes closed and remote, tense with anticipation.

He can't move. He can't even speak. All he can do is watch, frozen in mute horror, as the demons approach the shackled angel. Watch as they strip him. Watch as a sneering Alastair lifts bloodstained tools and goes to work.

He watches as Castiel is whipped. As he is flayed and burned and slashed. Bones are broken. Flesh bloodied and torn. Watches as hell fire is dripped over heaven's servant. He listens to the angel's hoarse screams of pain.

It isn't the screams that are the worst. It's the fierce serene resolve on Castiel's face. Even as he is tortured, there is a calmness in his eyes that terrifies Dean. As if he accepts what is being done to him. As if all his suffering is worth something. Even as he screams, the angel looks oddly triumphant. And Dean knows, instinctively, why.

Castiel swore to save and protect him. His place on the rack is a victory in his eyes. His torture is Dean's protection.

Dean wakes crying, choking on bile. He doesn't sleep again that night, or the night after. Sam worries, but is kind enough not to ask.

The night after that, they've completed a strenuous hunt, and Dean can't stay awake.

In his nightmare he stands before a tray of torture implements. Selects an ugly, slightly dull serrated knife. He's screaming in his head, but he can't stop himself, his body moving independent of his will. He turns.

Castiel is on the rack again. He watches his hands cut away the angel's clothing. The worn trench coat, the suit jacket and shirt and tie. The dark trousers. Watches himself strip the angel while Castiel watches him with knowing, understanding eyes.

He wants to cover the angel back up. Wants to throw down the knife and cut him loose. Wants to cover those too serene eyes, so he can't see Castiel's expression. Wants to weep and apologize. Wants to throw up.

But he isn't in control, and he can do none of these things.

He watches his hand make the first cut, ragged metal drawing blood from fair skin. Watches his hand cut into the angel who saved him from hell. The movement is smooth, calculated, but in his mind he's screaming, choking on the terrible wrongness of the situation. Castiel gasps and flinches and strains against his bonds, but his eyes are still serene.

The angel's body writhes under his touch, his careful carving, but his expression is intense, focused, calm. He looks...compassionate. As if his eyes are forgiving Dean even as the rest of him suffers.

It's unbearable. As his knife, heated to red hot in Hell fire, draws the first scream from his captive, Dean is screaming too. Screaming Castiel's name over and over, apologizing and begging both at once. His hands never stop, and it's agony to his heart.

A hand touches his shoulder, and he jolts awake, heart pounding, shirt soaked with sweat, face wet with tears.

A familiar form stands over him. He flicks on the light and stares at the person responsible for waking him.

Castiel, whole and well. Wearing his familiar suit and trench coat. Expression impassive, eyes concerned. Dean stares at him, and finally finds his voice. "Cas."

The angel regards him a moment, then answers softly. "I heard you call. You seemed distressed."

He sits up, eyes raking over the angel's body. Over the abdomen, covered by jacket and button up shirt, the pristine fabric proof that the skin beneath is whole, not slashed and burned and bleeding. Over the hands at Castiel's sides, undamaged, unbroken. Over his face, unmarked and relaxed rather than bruised and bloodied and contorted in pain. "Cas..."

He reaches out, lays a hand on the angel's arm. Feels the roughness of the trench coat, the warmth and solidity of the arm underneath. Castiel stands silent, waiting.

He swallows hard. "When you came for me...did you get hurt? Did the demons...?"

Cas tilts his head, looking faintly puzzled. But he answers. "I received minor wounds in battle. And slight injuries to my wings. Nothing else. When I raised you, I flew in and seized you so quickly there was no time for the demons to react."

"You weren't...they didn't..." He doesn't want to articulate it any further. He's afraid to ask Castiel if the angel was tortured for him. Afraid to hear that it might have happened.

"No. I was not...assaulted. My comrades watched over my flight."

Which leaves the last question, the one he's really afraid of. "Did I hurt you? When you nabbed me?"

Castiel considers. "You resisted when I gripped you. I do not believe you understood what was happening. You fought. But you were not capable of doing any damage to my form."

He doesn't remember his rescue. But he remembers another meeting. "When I stabbed you with the demon knife..."

"I was...perturbed, but unharmed. You did not hurt me."

Relief fills him, and he bows his head, breathing deeply. He didn't hurt Cas. He didn't hurt the angel who saved him from Hell.

He grips the angel's arm tightly, trying to figure out what to say. How to articulate the feelings that burn through him.

"What's wrong, Dean? Do you need assistance?" Castiel's voice, so concerned.

He shakes his head. "I'm good. I'm good. Just...you be careful, okay?" He looks up into the blue eyes. "Be careful. Don't let those black-eyed bastards get you. And if..." He swallows hard. "If I do something, if I ever hurt you...you stop me."

Castiel tilts his head again. "Dean...I am an angel..."

"I know, I know. You're an angel, and I'm a regular guy. But still...you stop me. You got that?" He needs the reassurance that, even if Castiel does get captured or tortured by demons, the angel will never be his victim.

Castiel studies him a moment longer, then nods. "You have my word."

Good enough. He flops back into the bed. "Thanks." He sighs, checks the clock. 2 am. "I'm gonna try and get some more sleep. You can stay, or go do what you gotta do. Whichever."

"I will...stay for a while." He hears the rustle of Castiel settling in. He closes his eyes.

It's good to have Cas there. Even if it should be creepy, to have the angel watching him while he sleeps. It's still good. Reassuring, for now at least.

It means Castiel is safe. There was a time when that wouldn't have mattered, when he wouldn't have cared. But if he's gotten anything from his nightmares besides the adrenaline and angst, it the understanding of what it means that Castiel is there instead of Sam.

He knows what it means, that his dreams have changed to include this exasperating, confusing angel. And he's glad that, just for tonight, he can sleep knowing that his brothers, by blood and choice, are safe beside him.

Author's Note: This one just popped into my head.