This was my piece for The Great Blind Sassy Exchange 2.

Castiel struggled against the restraints that held his wrists against the wooden cross to which he was bound. Impossibly they were stronger than he was, and try as he might he couldn't break them. With a grunt of defeat, Castiel looked over to Dean, lying unconscious in a heap on the floor nearby.

"Dean," Castiel called out to him, tasting the blood in his mouth as his tongue formed the word. "You have to wake up. We have to go – "

The slam of the door flying open echoed through the tin walls. He walked in, swaggering about like he owned the body he was wearing. He didn't though. That body was Sam's. That thing had stolen it.

"Sorry I had to step out, rude of me." With a lazy blink Sam's hazel eyes disappeared behind a veil of black. The thing twisted Sam's mouth into an ugly grin as he moved closer. "Did you miss me?"

"Fuck you," Castiel spat.

"Tsk, tsk." The noise sounded foreign on Sam's lips. "It seems our fun hasn't tempered your manners. I'll have to fix that."

The weight of Sam's hand traveling down his side sent a jolt of nauseous familiarity through Castiel. The pressure was wrong, the movement slower and more maliciously taunting than Sam's touch ever was, but the warmth of the body had a signature of its own, and Castiel tensed as those fingers brushed his hip. Castiel was only further disheartened by the sound that followed: the smooth steel of his blade leaving its sheath.

"You thought I didn't notice your little toy?" Sam's voice taunted. "You underestimate me, Castiel."

Castiel concentrated hard on remaining silent. The demon inside of Sam was very powerful, and was unpredictable as far as he could tell. He decided it would be best not to engage it, and to that end kept his mouth firmly shut. The beast did not share his burden, however, and was glad to fill the silence with his own musings.

"Castiel - an interesting name. 'My cover is God.' Very old, very noble and prophetic, or it was meant to be. Look at you now, my friend, at the mercy of one of Lucifer's creatures. Your strength has left you. Your name is a hollow title. You aren't of God anymore, are you? Tell me, is that why you let them call you Cas?"

Rage coiled in Castiel's stomach. He struggled against his restraints, but to no avail. They held strong. The demon forced Sam's features into that ugly smirk once again, and he now balanced Castiel's sword between Sam's palms, handling the deadly weapon with playful disregard.

"Yes, I know what they call you. I know everything, really. See, Sammy here is just a fount of information. Some of his secrets are more surprising than others."

It grasped Sam's hand around the handle of the blade and used it to gesture to Dean, still lying lifeless on the ground.

"Tell me," Sam's voice whispered. "Does Dean know what you do to his little brother when no one else is watching?"

Castiel's eyes darkened, his breath caught, but he managed to remain still and stoic. That seemed to be answer enough.

"No, I thought not. Sam prefers it that way, you know. He wants to keep you to himself."

Castiel didn't rise to the bait; he was too terrified. The demon seemed pleased with this new discovery, and Castiel wasn't keen on finding out how he planned to use the information. After a beat of waiting for a reaction that never came, Sam's voice sounded in a disheartened groan and his arms flew up in a display of frustration.

"It's like talking to a wall!" The demon made Sam shout dramatically. Then suddenly he was right up in Castiel's face, inches separating them as he dropped Sam's voice to a murmur.

"How can we make this more interesting for you?" The tip of the angel blade glided in a gentle caress down Castiel's cheek. "I know, what if I wake Sammy up? Not all the way mind you, just enough that he can feel what I'm going to do to you."

If Castiel reacted it was fleeting, but their close proximity allowed the demon to catch whatever flash of emotion Castiel was unable to contain before he placed his features back to their positions of stony indifference.

"Yes, I think I will. Seems like a fine idea to me. In fact, I bet if you watch closely you'll be able to see the terror in his eyes."

Castiel watched the onyx fade away as Sam's natural irises were restored. Suddenly, the wall keeping Castiel's emotions in check began to crumble. He knew that this wasn't a trick. One look into Sam's eyes told him that Sam was looking out at him from a cage of his own flesh, screaming for help that wasn't going to arrive.

"It's okay, Sam," Castiel promised, fighting to keep his voice steady. He hissed as the angelic blade nicked his jaw. Sam's hands guided the blade down the hollow of Castiel's throat, gently, not piercing the flesh. His tie was cut away unceremoniously, and then the top button of his shirt. The blade was cool against his skin as it traveled down, slicing open the fabric one fixture at a time. When the last button gave way the blade pushed aside the fabric, and Sam's head tilted strangely. The demon was assessing.

The scars were still there from that day long ago when Castiel had carved the words of his people into his own flesh to clear the way for his charges to stand against the apocalypse. New gashes had been cut over the old scars to distort the pattern – Castiel didn't want any accidents – but the original lines were still raised pink on his pale skin, and it was easy enough to make out the sigil.

"What happens to an angel when you banish him into himself?" Sam's voice purred in Castiel's ear. Castiel didn't respond, but then the tip of the blade pressed in the top of the circle on his chest, cutting open his old scars, and he couldn't help but scream out.

"Louder, Cas!" Sam's voice demanded with a sickening laugh. "I'm not sure Sammy can hear you."

"Sam," Castiel said through gritted teeth. "It's okay, Sam. It's not your fault."

A fist – Sam's fist – came down across Castiel's face. There was a crack as Sam's bones failed to survive the impact, but the force behind the blow was stronger than just the human power of Sam Winchester, and Castiel felt his lip split. There was the taste of blood in his mouth, the warm wetness of it spilling down his chin, and another bolt of white-hot agony as the blade resumed carving the Enochian symbol into Castiel's skin.

"Sam is absolutely screaming!" A delighted laugh reached Castiel's ears, though he found it hard to concentrate on the sound. He was growing woozy from the pain. "He's begging me to stop. He must love you, Castiel. It sounds like he's really suffering."

"Sam," Castiel whispered.

"You're not going to survive my little art project, are you Cassy?" Sam's voice asked mockingly. "That's a shame. I wanted Sam's hand pressing into your bleeding chest to be your send off into oblivion. Ah, well. The chorus of your screams will do."

The next scream that sounded wasn't Castiel's. It wasn't Sam's either, though it definitely came from the direction of his body. It was the sound of the demon, crying out from deep within his host, and Castiel blinked as he tried to figure out why. It took a minute for Dean to come in to focus, standing over his brother with a newly empty flask of holy water in his hand. Sam was curled up on the ground, the demon screaming against the burns, but they knew it was temporary. He'd recover quickly.

Dean made quick work of the restraints holding Castiel hostage, and without the support Castiel fell heavily into Dean's arms. Dean tried to support him, but Castiel pushed him away, and stumbled forward to press his hand against Sam's forehead. It took everything left in him, but Castiel surged power into the contact, and felt a twisted pleasure when he felt the demon inside of Sam burn.

Castiel's knees gave out the second it was done. The adrenaline faded quickly, and he could feel fully the pain in his chest and the weakness in his vessel. Sam sat next to him on the floor, blinking rapidly from disorientation, until finally his eyes fell on the blood coating Castiel's torso. All the color drained from Sam's face in an instant.

"Cas," he breathed, moving towards the injured angel. Castiel shook his head.

"It's okay, Sam," Castiel said weakly. He shifted so he was sitting on his heels and tried to look composed for Sam's benefit. The look on Sam's face told him it was a poor show.

"I'm sorry." The apology broke from Sam's chest in a sob. He threw his arms around Castiel and buried his face in his neck, warm tears falling from his eyes and wetting the angel's skin. Castiel hissed slightly at the contact as Sam brushed against his wounds, but then he wrapped his arms around Sam in response. He brought his hand up to brush through Sam's long hair and whispered comforting words in Sam's ear.

If Dean found anything strange about the interaction, he didn't comment. He simply excused himself, saying something about getting the car. Castiel and Sam didn't pay him much mind.

Sam woke the next morning to the polytechnic ring of Back in Black, followed by the low sound of Dean whispering into his phone.

"Where are you?" Dean asked the person on the other end. "I wish you would've stuck around last night, you were in pretty bad shape."

There was a beat as Dean listened to the caller speak, and then he shook as head as if the other person could see the movement.

"No I haven't slept yet … It's a human thing, you aren't supposed to sleep after a head injury … Sam? I don't think he slept very well either."

Sam turned his head and blinked at the sound of his name. He could guess who Dean was talking to now.

"He was tossing and turning all night – Oh, he's awake now."

Dean grinned at Sam, then pointed to his phone and mouthed "Cas." Sam nodded and tried to swallow the fresh wave of guilt as the events from the night before came rushing back to mind.

"We're at the same motel as before … Yeah … Stop by whenever you're up to it."

Dean flipped his phone shut and looked at Sam critically.

"How are you feeling?"

"My hand hurts," Sam answered. He looked down at his bandaged hand and remembered with sick clarity the sensation of it coming down across Castiel's jaw. "But otherwise I'll be all right."

Dean was obviously not completely satisfied with that answer, but he accepted it. He rose to his feet, and when he turned Sam could see the sizable lump on his brother's temple. Dean hadn't mentioned it, and Sam couldn't remember, but he knew he had been the one to put it there.

Dean must've caught sight of the look on Sam's face, because his own expression softened all of a sudden.

"It wasn't your fault Sammy," he said seriously. "We don't blame you. Neither of us – we're just glad you made it through in one piece."

"Cas didn't," Sam said so quietly Dean almost didn't hear him.

"Cas will be fine," Dean assured him. "He went somewhere private to patch himself up last night, and he's coming to meet us later. Stop beating yourself up."

When Sam didn't respond, Dean sighed and changed the subject.

"I'm going on a breakfast run, you want the usual?"

Sam frowned. "You might have a concussion. You shouldn't be driving."

"I've driven with worse." Sam's frown deepened, and Dean gave him a Cheshire cat grin in response. "I'll be fine. If I'm not back in twenty minutes send the cops."

"Don't think I won't," Sam warned. Dean waved at him dismissively as he pulled his jacket on over his t-shirt. Then he walked over to Sam's bed, and curled a finger under his chin to make Sam look at him.

"It's over."

Sam could only nod. Dean clapped him on the shoulder then turned to leave, calling "Twenty minutes!" over his shoulder as he shut the door behind him.

Reluctantly, Sam got out of bed. He went into the bathroom and cranked the shower to the hottest setting, but after a couple minutes he decided it wasn't hot enough and the pressure was inadequate for relieving the tension in his back. He shut it off.

As he brushed his teeth, Sam's eyes fell to his bare chest in the bathroom mirror. Besides his hand, the only wounds to show he had been in a battle yesterday were a series of deep gashes from when the demon had thrown him through a window. The deepest of them cut along the top of his peck, effectively bisecting his anti-possession tattoo and rendering it useless. Sam threw his toothbrush down and clicked the bathroom light off. He didn't want to look at his reflection anymore; he was too frustrated with what was looking back.

He picked a pair of jeans up off the floor and pulled a t-shirt out of the duffel bag in the corner. When he was dressed, Sam flopped backwards on the bed and covered his face with his hands. It didn't matter if they forgave him. He could still feel his hands moving without his permission, pressing the blade into Castiel's skin. He could still hear Castiel scream. He could still see the color drain from the angel's face as the space around him shone bright with dying grace. It had happened, and it wasn't going away. No matter what they said, everything wasn't all right.

Sam heard the sound of Castiel's wings only a few seconds before he felt the bed dip under the weight of another presence. He refused to open his eyes; he wasn't even sure he could if he wanted to. After a long moment of silence he felt a hand brushing gently across his forehead, moving stray strands of hair out of his face.

"Sam," Castiel said softly. "Look at me."

Sam pulled his hands away from his face and opened his eyes to find his vision blurry. He hadn't noticed the tears in his eyes until now. When he tried to blink them away the tears escaped down his cheeks, and Castiel reached down to brush them off with his thumbs.

"I'm fine," Castiel promised, and it was true. He looked tired, but the color had returned to his face, and he wasn't in any visible distress like the last time Sam had seen him. In fact he was quite characteristically calm.

"I'm so sorry Sam," Castiel went on. "What the demon did to you was cruel."

"He almost made me kill you." Sam's good hand came up to cup Castiel's cheek, and Castiel leaned into the contact.

"I know."

Sam scooted over and gestured for Castiel to lie down next to him; the angel was happy to comply. They entwined their limbs until Sam could no longer tell what belonged to whom, and pressed their lips affectionately to the parts of each other that they could easily reach. For once he had Castiel completely in his embrace and sex was the farthest thing from Sam's mind. He just wanted to have him living and breathing in his arms, and he could feel from the way Castiel clutched possessively at the back of his shirt that the feeling was mutual.

Sam could feel himself drifting back to sleep. At some point he heard the door open, and heard a quietly bemused "Huh" in his brother's voice before it closed again and the Impala roared to life somewhere in the distance. Sam didn't care much. All that mattered was the fact that the nightmare was over.