"What happened, Dean?" Castiel asked the hunter-turned-demon for the third time. He narrowed his blue eyes, trying to look intimidating, but he highly doubted the tactic was working. Normally people weren't afraid of someone who could barely stand on their own. Or angels with no powers… he thought bitterly.

"I told you already, you soulless dick, I'm not telling you anything. And you can't make me." Dean leaned against the back of the chair with a smug expression plastered on his very evil looking face. Castiel had never seen Dean so full of hatred and contempt before and the sight made his stomach churn with unease and something else… he glanced quickly at Sam who stood a few feet to his left, silently pleading for help.

The younger Winchester only shrugged in defeat, obviously he'd already tried everything he could think of to get some answers out of his brother, but Dean wasn't cooperating.

"Well, if you think we're so useless, what harm could telling us what the hell is going on possibly cause?" the angel let a little bit of annoyance creep into his normally flat voice, this was getting ridiculous, they'd been trying to get something useful out of Dean for nearly a half hour and he wouldn't talk.

"I'm not falling for your crap, I told both of you idiots, I like being a demon, I like not caring, and I like not having to worry about you." Dean licked his lips slowly, his eyes wandering with scrutiny up and down Castiel's body, like a dog sizing up its prey.

Shifting uncomfortably, Castiel looked away for a moment. He might always be messed up from what Dean had done to him but he still wanted to help his friend get better. No matter what.

"What's wrong, angel? Did I hurt your feelings?" mocked Dean, his mouth pouting in a fake frown.

Emotions that Castiel couldn't explain filled his chest. They hurt. And made his face heat up like someone was holding a match too close. He struggled inwardly with these new found feelings until he found something he recognized, something he could cling to that made sense.

Breathing out slowly, Castiel let his anger drowned out all other emotions, his exhaustion, his pain, the way looking at Dean made him want to strangle him and kiss him at the same time… everything.

"No." he growled, taking a step towards Dean, who smiled slightly and strained his arms against the ropes holding him.

"Cas…" Sam moved to put a hand on the angel's shoulder but Castiel shrugged him off.

"Look." Castiel lunged forward, gripping both Dean's arms tightly in his hands and leaning down until their faces were mere inches from each other. Blue eyes boring into green in one of the most intense staring contests they'd ever had. "We can do this the hard way, or you can just tell me. Either way, I will get what I need out of you." He let his voice drop even lower in warning, his jaw set firmly.

Dean's eyebrows raised in questioning. "Oh really? What are you going to do? Smite me?"

"If I need to." This time it was Castiel who grinned. Standing back, he let his remaining grace flow through him. The air in the little room started to hum softly and the single light overhead flickered. Suddenly this wasn't about helping Dean; no, this was personal. How dare this human think he could treat him with such disrespect and get away with it? After all Castiel had done and sacrificed for them, how could he even think that…

"Take it easy, Cas." Sam sounded worried and Castiel felt a hand on his shoulder.

"Get off me!" the angel snapped, jerking his wrist and pushing Sam back a few feet.

The blub hanging from the ceiling exploded and blinding white light materialized out of nowhere around Castiel, shadowing his outstretched wings against the far wall. The power felt weak, but he didn't care, he focused on the anger, and the need to destroy the source of his suffering… Dean.

"Don't hurt yourself, kitten." In spite of his pretentious words, Castiel detected a hint of uncertainly in the older Winchester's voice. He tilted his head slightly, not even sure he could hurt Dean at all, let alone kill him. He loved Dean, yet he hated him at the same time.

"What did you call me?" Castiel demanded, the nickname felt familiar, though he couldn't pinpoint it. His brain wouldn't work past the rage and sorrow flooding his senses like poison. The edges of his vision turned red and Castiel started breathing harder.

"Whatever I want." Dean replied, though his eyes darted nervously around the room.

"I'm still an angel, Dean." Castiel growled the name like it physically hurt to say out loud. "And you should show me some respect." Stretching out his hand palm first, fully intent on killing this demon scum in front of him, Castiel closed his eyes, even as they burned with hot tears.

"Castiel! Stop!" Sam suddenly shouted, and Castiel faltered, his eyes flickering open as he glanced quickly at the younger Winchester.

Sam looked confused, and maybe a little scared. This wasn't right, he didn't want to hurt Sam. Castiel lowered his hand slightly, his vision becoming a little less clouded with rage.

"Please." Sam whispered, his soft, burden filled eyes pleading.

Exhaling harshly, Castiel blinked and lowered his hand, releasing the grip on all his rage with the simple gesture; unfortunately all his energy seemed to leave with it. The angel collapsed to his knees with a half hearted grunt.

Just a quickly Sam was kneeling next to him, gripping his shoulders, hauling him up off the floor like he was little more than a ragdoll.

"Shit, Cas. Are you okay?" asked Sam worriedly and Castiel snorted bitterly. Here he'd nearly killed his brother and Sam was concerned about his wellbeing? He didn't deserve anyone's sympathies or even the simple care given a good friend. Numbly Castiel nodded, staring at Sam with blue eyes that had long lost their spark. Breathing, even living, seemed too much effort; he'd lost everything, his home, his grace, and now Dean.

"Come on." Sam wrapped Castiel's limp arm around his broad shoulders and proceeded to walk him towards the door. Despite Sam being as gentle as he could the movement still hurt and Castiel couldn't be bothered to bite back the little gasps of pain that made it past his chapped lips.

Dean's satisfied snickers made him want to vomit. He couldn't stop wondering if the real Dean had meant any of those things he'd said. Chancing a glance over his shoulder, Castiel caught sight of Dean's evil smirk, his green eyes cold, void of any empathy; dead – exactly how he felt.

xxxxx

"Sam, I'm so sorry, I don't what came over me." Castiel apologized for probably the fifth time since they'd headed upstairs. They were sitting in the main room trying to figure out what to do next. But the angel couldn't seem to rid himself of the remorse and guilt he felt over his previous outburst. He gripped the coffee mug in his hands tighter, as if it would somehow make the situation better.

Sighing, Sam rubbed a hand down his face and shook his head at the angel sitting across the table from him. "It's not your fault, Cas. I shouldn't have taken you down there. You weren't ready to deal with that."

"I'm fine." Castiel insisted stiffly, though honestly he felt anything but fine. His head wouldn't stop pounding, he was freezing and couldn't stop coughing, the warm liquid he'd been drinking only helped cover it. And most importantly, Castiel was heartbroken, there seemed no reason to keep fighting. He hated to admit it; but he loved Dean, and if they couldn't fix him Castiel couldn't bear the thought of having to live forever with Dean as his sworn enemy – a demon.

"No, you're not fine." Sam's voice brought him back to the present and Castiel was about to open his mouth to argue when the hunter continued with an exasperated sigh. "And neither am I."

The angel's mouth snapped shut and he frowned in confusion, not sure he'd heard correctly; since when did Winchesters admit when they weren't handling things?

"We can lie to ourselves, and even each other, but it doesn't change the fact, so what's the point? I'm not going to be okay until Dean is Dean again." Sam looked at Castiel with a mixture of hope and guilt. "And I know it's a lot to ask, but I don't think I can do it without your help."

Castiel pulled the blanket Sam had given him earlier tighter around his body and smiled sadly. "Well," he sighed heavily, "you saw what my 'help' looks like, pretty sure you could do just fine without that."

"You have to stop beating yourself up, Cas." Sam averted his gaze, a slight blush coloring his cheeks. "Look, I don't really know what's been going on between you and my brother, you know, these past few months… or whatever. But I know you two are close, so I'm sure what he did messed with your head, demon or not, it was still Dean. It's just going to take you a bit to get over it."

Shifting uncomfortably, Castiel shrugged, hoping Sam would drop this super awkward subject and never mention it again. It wasn't that he didn't trust Sam, he was pretty sure the younger Winchester would be supportive of any relationship between him and Dean, but the amount of humiliation he now felt regarding the entire thing made him completely unwilling to let anyone know he'd ever wanted to be – let alone had actually been – intimate with Dean.

Apparently Sam felt weird mentioning it too, because he cleared his throat and stood up with an audible huff. "So what do you say we get human Dean back, and then you can beat the living shit out him."

Castiel nodded slowly, just as a sudden realization hit him square in the face. "And I think I know where to start."

"You do?"

Castiel looked up at Sam, a little bit of the life returning to his features. "Dean called me a kitten." He stated, scanning the table in front of him for a phone.

"So?" Sam shook his head in confusion, obviously not following.

"Well." Castiel paused his search to focus his attention on standing up, which proved more painful and took a lot longer than he would have liked. He grabbed in the edge of the table to steady himself just as Sam came around and placed a hand on his shoulder for support.

"The only person who's ever called me that was Crowley. And no one else was there, so I would conclude that either, Dean being a demon somehow gave him a whole new outlook on nicknames, or he's been hanging out with Crowley." Castiel smiled triumphantly at Sam, maybe he wasn't completely useless after all.

"That's something." Sam agreed, pulling his phone from his pocket and dialing the King of Hell's number.

Sam glanced nervously at Cas and back to his phone as it rang loudly in his ear. Come on, pick up you dick!

"Moose!" exclaimed the familiar, overly thick accented voice at the other end. "So nice of you to call, to what do I owe the pleasure?"

"Listen, Crowley." Sam snapped shortly, in no mood for the demon's bullshit. "We know you and Dean have been, hanging out. So what did you do to him?"

"What? Not even a hello first?"

"Crowley." Sam warned, once again eyeing Cas who had slumped back into the chair and appeared only half conscious. He clutched the phone in his fist, they were running out of time in more ways than one. "You better answer my questions straight, got it?"

"Or what?" Crowley taunted.

"I have your number, and I will find you." Sam said with as much force as he could muster.

Crowely sighed, sounding bored. "We've mostly been bromancing our way across the countryside, banging chicks, drinking beer, sealing soul deals every now and then."

"What?" Sam wiggled his nose in disgust as he sat down by Cas and put the phone on speaker so the angel could hear the conversation. "That's not what I'm talking about, and you know it."

"Oh! Of course. You mean why is he a demon? Perks of the Mark, I suppose. Now if you'll excuse me, I have more important things to attend to."

"Wait. So you didn't do this?" Sam wasn't convinced, he shared a glance with Cas, both shaking their heads slightly in agreement; that Crowley was a total dick.

"Crowley. We know you know what happened." Cas looked like he was about to pass out, but he somehow managed to keep the exhaustion out of his voice.

"You're right, angel, I do." Crowley's smirk could practically be heard through the phone. "See, here's how it works. Dean has the Mark of Cain. Following so far?" he paused and Sam rolled his eyes, fighting the urge to hunt the stupid demon down and demand he give them all the information right now or it'd be hell to pay… or something like that.

"When someone with the Mark dies, they become a demon, also known as a Knight of Hell. It's all part of the curse. And it can't be cured by your little purified human blood trick, which I'm guessing you already found out and that's why you called, right?"

Sam felt his heart sink with dread and one look at Cas told him the angel felt no better about this news. This couldn't be happening! This had to be one of Crowley's lies to get in his head.

"You're lying." Sam said evenly, hiding the fear constricting his chest like a torture device.

"So Dean is no longer a demon?"

Biting his lip, Sam tried to conjure up a good response that would somehow get Crowley tell them what they needed without him getting conformation either way, but he couldn't think of anything. It didn't help that he'd barely slept or ate for three days straight.

"How do we cure it then, you assjerk?" Cas demanded, staring at the phone like a drunk man trying to focus on the spinning room.

"Who taught you to swear?" Crowley snapped in annoyance and Sam couldn't help the small smile that tugged at the corners of his mouth. Cas was horrible at insults, but he tried, the poor guy. And when Cas turned his confused gaze to him, Sam had to bit the inside of his mouth to keep a straight face.

"Just tell us, Crowley." Sam rubbed his temple to ease the headache he felt coming on. Even with his pressing concern for Dean ever present in his mind, dealing with Crowley was enough to make him want to kill someone.

"Simply put, there is no cure. Even if you somehow manage to bring him back, it will only be temporary; the next time he dies he'll become a demon again." Crowley chuckled. "And if I'm guessing correctly having Dean with the Mark, demon or not, it a little more than you and darling little Castiel can handle."

"Crowley…" Cas growled.

"Sorry, no cure, mean's no cure." The demon said with fake remorse. "Dean is your problem now, have fun."

There was a slight click as the line went dead and Sam slammed his fist angrily against the table. Now they were back to square one; worse actually, now there was the possibly that Crowley had been telling the truth about Dean being a Knight of Hell and maybe there really was no curing that.

"Crowley lies, Sam." Cas said wearily as if reading his thoughts.

"But what if he's not?"

"I don't know…" Cas appeared to pale even more, like he couldn't handle even thinking such things. Sam scrunched his eyebrows together. He knew something was going on between those two, but he had a feeling Cas wouldn't be enlightening him on the subject any time soon. "But I bet you if there is a way the Men of Letters wrote about it and it's in here somewhere."

A tiny spark of hope flared in Sam's chest and he nodded. Please be right, Cas. He prayed silently to himself. Please be right.

xxxxxx

It hurt. Everything hurt. Why was everything so intense? Castiel wasn't used to being in pain for long periods of time and it seemed the more he tried to ignore it and focus on the book in front of him the worse it got. Normally any discomfort he felt in his vessel was muffled, a mere annoyance he could dismiss without much trouble.

But now that he didn't have his own grace anymore he was stuck with this body and all the perks of being a real angel didn't apply to mostly used up stolen grace, all it did was keep him alive.

They'd gone to the library after the discouraging call with Crowley, digging up anything they had on Knights of Hell and curing demons. Castiel had taken on the task of reading up all they had about the Knights of Hells. Which wasn't much. Apparently before Abaddon had come and murdered everyone no one had actually seen a Knight of Hell, so most of the lore was just speculation. In fact, he hadn't seen one thing in this book that he didn't already know.

Castiel set the book on the table in front of him, sighing in discomfort as he did. He chanced a quick glance at Sam, who sat just to his left with a stack of books piled in front of him. The hunter appeared totally engrossed in the book he held in his hands and didn't notice the angel staring at him.

Crossing his arms to use as a pillow, Castiel let his head sag, sleeping sounded like an amazing idea right now. Leaning forward put pressure on his wounds and he moaned slightly against the pain, biting his bottom lip to keep from making more noise. The agony in his chest every time he breathed seemed to drain all his remaining energy. Castiel fidgeted in his chair until he found a position that was bearable and closed his eyes, willing himself to focus on anything except the pain and all their problems.

He'd hardly had his eyes shut for five minutes when he heard Sam calling his name through the fog of fatigue and pain wrapped around his mind. He wanted to be mad at Sam for disturbing him, but how could he be? The younger Winchester had been nothing but kind to him, even when he didn't deserve it.

"Hmm?" Castiel grunted, not even bothering to try and move, hiding his misery was getting to be too much work.

"Cas. Did you hear me?" Sam asked.

"No." Castiel mumbled, lifting his head enough to look into the young man's concerned gaze. A world of doubt and grief reflected in his hazel eyes, making Castiel feel all the more a failure for being a useless burden.

"Do you need a break? You look horrible." Sam said, gesturing to the stack of unread books next to him. Oh how Castiel wanted to lie his way out, but he couldn't even manage that. "I'll keep looking through these and let you know if I find anything, you have to take care of yourself."

"I… It just…" Castiel averted his eyes to the table, feeling his cheeks flush with shame as he whispered the last word, "hurts."

"Oh. Oh shit! Cas." The angel winced at the grating sound the chair made as Sam pushed it back and stood up. "I'm sorry man, I totally didn't think… why didn't you say something? Just, just stay here. I'll get you some ibuprofen."

Castiel watched Sam leave the room, now slightly intrigued by this 'ibuprofen' Sam had been talking about. He didn't have to wait long, the hunter soon returned with a glass of water and two small orange pills in his hand.

"Here." he placed everything in front of Castiel. "Take these, they should help with the pain."

It took a good ten minutes but the sharp, stabbing pain finally lessened to a more tolerable dull ache and Castiel found he could actually focus on what he was reading.

"Thank you, Sam." Castiel said sincerely.

"Of course, Cas." Sam replied without looking up from the book he had titled Angel's Blood. Castiel felt a little uneasy and averted his gaze; they had a whole book dedicated to his kind's blood? How much could one possibly say about it anyway? And why was Sam even reading it? Didn't seem to have anything to do with what they were after. Castiel thought about asking but couldn't quite find the gumption.

Another ten minutes and Castiel's eyes were drifting shut of their own accord and he was about to take Sam up on his offer when the younger Winchester suddenly jumped out of his chair with such enthusiasm that Castiel couldn't help but share some of it.

"Look, Cas! I think I found something!" Sam was standing next to him in two huge footsteps and shoving aside the other things in front of Castiel to make room to set his book. "See?" he jabbed his fingers at the middle of the left page.

Castiel narrowed his eyes and glanced at the old document style writing before him. After skimming through he turned to Sam with a look of shock on his face. "Do you think this will work?"

"I don't know, but we have to try." Sam grabbed his jacket off the back of his chair and headed for the door. "You stay here and rest, Cas. I'll call you and keep you updated." He hesitated for a moment before adding. "And stay away from, Dean."

"No, Sam." Castiel said firmly, pulling himself out of the chair, only swaying a little before he steadied himself with a hand pressed to the table. Sam paused and spun around to face him.

"Most of the other angels already returned to heaven, who knows how long it would take you to track one down. And even if you can, why waste the time? Why take the risk? We have what we need right here." Castiel took a deep breath and stood as straight as he could, fixing Sam with his intense, unblinking gaze while he moved closer until they were only a couple feet apart. Sam licked his lips nervously, trying to avoid eye contact.

"We have what we need right here." he repeated calmly. "And I'll give it to you without a fight."

"Cas, no." Sam shook his head. "If I can't find another angel we'll just find another way, there's always another way."

"Sam…"

The look for utter despair in Sam's eyes made Castiel's heart ache and only solidified his decision. No matter what it cost, he had to do his part to insure Sam and Dean were reunited as family again.

"I said no." Sam waved a hand at him with irritation. "Come on, Cas. You're not strong enough, and it might not even work with your blood. Are you even a real angel anymore?"

Castiel tensed a bit, the words hurt; but he couldn't really blame Sam for questioning him, he hadn't exactly been the picture of angelic magnificence lately. Is he still a real angel? He doesn't even know anymore.

"Cas, I'm sorry-"

"I don't know." Castiel cut him off with a sigh. "I think I stopped being a 'real' angel a long time ago. But I'm the only angel you got."

Sam doesn't look convinced. "This is could kill you."

Castiel snorted bitterly, the mere notion that even mattered strangely humorous. "I don't see why that matters." he saw concern flicker across Sam's face and quickly added. "I'm dying anyway, Sam. And if I can help you get your brother back, then my death might as well serve some purpose."

"Cas…" Sam's face softened, like somehow he finally understood what was going through the angel's guilt ridden mind. "I can't ask that of you…"

"You're not." Castiel assured him, placing a gentle hand on his shoulder. "I'm offering."

"I don't like this." Sam told him.

"I'm not asking you to."

Sam nodded. "Okay." he agreed quietly. "Okay."