I couldn't say how long I sat like that, one hand delicately fingering the damaged plumage – but before I knew it, the feathers were whipped away from me and Castiel stood, head bowed, looking for all the world like a normal man – albeit a battered and bruised one.
I opened my mouth to question him, but closed it at the sound of the front door slamming.
"Dean? You home?"
"It's just my brother," I reassured Castiel quietly, before raising my voice. "In here, Sam."
My brother entered our modest dining room, covered in similar gore as I had been only a few short hours before – but in place of my tortured, dead eyes, there was an unmistakable glee. His hazel gaze landed on the angel stood before us, and he raised an inquisitive eyebrow. "This is Castiel," I explained hesitantly. "He was... a gift. From Crowley."
Sam's eyes flicked to me, switching to an eerie, flat black between blinks. "For you? Why?"
I shrugged, looking away, instantly nervous of the harsh creature I often found in place of my brother these days. "I dunno - to keep me on side, I guess? It's not a secret that I don't… That I'm not relishing my job."
"Unlike me?" Sam challenged, voice sharp and thick with jealousy. "Is there something wrong with doing well?"
"When the thing you're succeeding at is torturing humans? Yeah, I'd say there's something wrong with that," I quipped back, then sighed, standing beside the angel. "Look, I don't know why Crowley thought this was a good idea, but I'm not going to argue with the King of Hell. So now Castiel is here, and will be for the foreseeable future. Okay?"
Sam's eyes narrowed, flickering that sinister black once more, before he nodded curtly. "Fine. I've always wanted one of these, anyway. You," he added, glancing at the trembling creature beside me, still shaking, head still lowered, "get me a beer."
Castiel went to move obediently, but I grabbed his wrist, glaring at my brother. "He's not your slave."
"That's exactly what he is, actually. That's his whole purpose, right? To attend to our needs. All of our needs," he clarified, gaze skimming over the angel's body. My stomach churned, and I stepped forward, a menacing growl raising in my chest, but Castiel put a hand out to stop me.
"Dean… It's fine. He's right. This is what I'm here for," he breathed, barely audible, voice cracking almost imperceptibly. I swallowed around the lump in my throat, opening my mouth to retort, but Castiel was already moving, popping the top from a beer and offering it to my brother.
"Thank you, pet," he crooned, raising a hand to tousle the angel's hair, and I saw Castiel wince.
"He has a name," I snarled, eyes narrow. "His name is Castiel. He's not your 'pet'."
I saw the muscles in Castiel's back tense, and he desperately flicked a hand at me by his side, warning me off, but this time I ignored him, moving closer to my brother.
Sam bared his teeth, his gaze settling black now. "He's whatever I want him to be, I imagine. He's living in my home, and will therefore live by my rules. And you'd do well to remember that, brother dearest. I have more sway here than you do." He let out a hum - a carefree, easy sound that filled me with dread. "I wonder if my rank would be able to put you back on the rack?"
My blood froze, all fight flowing from my body. "You… You wouldn't do that to me," I stammered, hoping it was true. When Sam shone a predatory grin in my direction, I knew my brother was truly gone, replaced by something twisted beyond recognition.
"Stay out of my way, and you won't have to find out," he breathed, before turning to Castiel. "You. With me."

I lay on the sofa, one arm draped over my eyes, trying to block out the sounds coming from the room with loud mental renditions of the best rock anthems. I couldn't shake the memory of Castiel slinking after Sam, his shoulders drooped, but his spine straight - even in this, he showed self-respect, despite his subservience and defeat. I knew he didn't regret the choices he had made - but I couldn't help harboring regrets of my own as I sat trying to deny the reality around me. Fear kept me motionless, helpless, even when my soul screamed at me to stop this.
I can't go back on the rack.
Hundreds of souls had passed under my knife, and each one was because of that overwhelming, all-encompassing truth. No matter what, I could not go back on the rack. Even if it meant allowing a monster in place of my brother to rape an angel.
Briefly, I considered finally utilizing my demonic nature, blocking out all feeling, but I knew that would be the coward's way out.
This was my fault, and the least I could do was endure it, just as Castiel had to.
When the angel finally reappeared, redressed and looking unruffled, I sat up sharply. "Hi," I breathed, relieved it was over - at least for now. He simply nodded, moving to the fridge for another beer, and returning to Sam's bedroom briefly before heading toward me.
"Is there anything I can do for you, Sir?" he murmured stiffly, kneeling by my side, his head still bowed. My mouth worked wordlessly, and I reached out to gently raise his chin. He flinched but allowed the motion, and I swore under my breath as I lifted his head, his cerulean eyes still refusing to meet mine. The angel's throat was a mess of fresh bruises, still fading from violent red to a vicious purple.
"I'm sorry," I whispered, tears stinging in my eyes. "I'm so sorry. I… I should have…"
Castiel shook his head slowly, still not looking at me. "I have a role to fulfill, Sir. I serve happily."
I couldn't help but flinch, delicately releasing my grip and allowing his head to fall back down.
Sam cleared his throat as he appeared in his doorway, bare-chested, still streaked with blood and other, unidentifiable stains, his gaze locked on the angel. "Do you need him for anything? Because, if not…"
I panicked, resisting the urge to pull Castiel behind me, hiding him from that rapacious grin. "I need him," I counted swiftly, mind whirring. "I… I haven't had a go yet, you know?" I raised a single, suggestive eyebrow, and Sam laughed.
"Enjoy. Crowley trained him well."
I swallowed the bile in my throat and stood, jerking my head at Castiel. "Come on."

Closing my bedroom door with a soft click, I exhaled heavily, resting my forehead against the dense wood. "I'm sorry. I just- I couldn't…" I trailed off, turning to the angel, and froze as I saw his hands begin to raise his shirt, moving to grab his wrists as it reached his chest. "Cas, no. No. I'm not… We're not going to… I just needed to get you away from him."
Castiel hesitated, and slowly, finally, made eye contact with me, his own filling up. "Really?"
I nodded firmly, releasing his wrists and smoothing his shirt for him. "Really. I will never… I couldn't do that to you."
His mouth moved wordlessly for an instant before he lent into me, head tucked into my throat, shoulders quivering as he sobbed against me. I froze, stunned, before gently wrapping my arms around his shaking form, tears of my own stinging behind my lids as I rested my cheek on his hair. "Hey, hey… It's ok. It's ok."
He whimpered softly, salting my collarbones as he cried, releasing months of torment and abuse. I simply stood quietly, lightly stroking his ruined back though the thin weave of his shirt, mindful not to harm him any further.