Demon! Alpha! Dean and Angel! Omega! Castiel.

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Edited 1/15/23: Updated tags- Omegaverse. D/S elements. Mentions of alcohol use. Mentions of drug use.

Castiel stirred, lifting his head as the heavy bolt clanked back. Swallowing dryly, he dragged himself upright and pushed himself back into the nearest corner, pinning his wings flat to his back, making himself as small as possible. Chains clattered, dragging against the cement floor of his cell as the door creaked open. It was hard to tell who it was, he was in a dark room with no window, the light in the hall silhouetting a figure. It took a moment before he was able to recognize them.

Honestly, the Omega had stopped trying to keep track of how long he'd been here. Long enough most of his feathers weren't white anymore. Nor were his clothes, but that was a different matter. Anything would be dirty after heaven knew how long in a dank cube with a hole for a toilet and rags for a bed. Particularly when it had been a knee length shift to start with. He'd had underwear at the start of all this, but they were long gone. Aside from his twice-daily ration of water and stale bread, there was only one reason someone would come to see him now.

It was his own fault he was here, Castiel knew that. The other Angels had warned him. Don't leave heaven, don't disobey our laws, don't risk an encounter with Demons. Omegas weren't meant to be warriors, it wouldn't end well. But Castiel had been curious, too curious. He'd snuck down to Earth one day to watch humans up close and paid the price for it. Night had fallen in the area he'd chosen, and unbeknownst to him a Demon had taken notice. That Demon had caught him before he could get back to heaven, slapping chains covered in binding sigils over his wrists and ankles and dragging him down to hell.

Halfway there another Demon had caught him, one who had slit the other Alpha's throat and brought Castiel to the dungeons rather than the bedchambers, though the improvement was questionable. While he'd never been the most obedient Angel in the heavenly host Castiel had no idea what he'd done to deserve this. For days Demons had fought over him, something about wanting a taste of virgin Angel Omega ass. Apparently it was quite coveted. So much blood had been shed by Demon Alphas that some had actually leaked into his cell as they fought in the hall outside. A few had gotten the door open, trying to get to him before others had grabbed them, dragging them back out. No one had thought to feed him or bring him water, and while he wasn't a human Castiel did need sustenance.

How long it went on the Omega had no idea. All he knew was that one day it all fell silent. A little while later an Alpha with blood splattered clothes had opened the door of his cell, bringing in a tray balanced on one hand. Castiel's mouth had watered at the sight of burgers, an apple, a bowl of soup, and a goblet full of fresh, clean water. He'd stood slowly, looking from the tray to the Demon carrying it. When he'd tried to reach for it the Alpha had stopped, holding food and drink out of reach, teeth flashing white in a smile.

"Not yet, Angel." After kicking the door shut with a resounding clang he asked, "How about a deal?"

"I won't make a deal with a Demon."

"You sure? It's been a week. You must be starving by now. I know I'd be." He set the tray down on the floor by the door, picking up the apple. He took a bite, gaze focused on the Omega as the fruit crunched loudly.

Castiel's mouth had gone dry, eyes zeroing in on the fruit. He was indeed starving. "What do you want?" he'd whispered hoarsely.

The Demon had smirked at him. "I want you to let me turn every single one of those pretty feathers of yours black. Let me get started and you can have all this. Once you're a Fallen you can get out of here. Think you'd like that? A big bed, room with a view, the works. Knights of hell get pretty sweet digs."

At first the Omega had refused, shrinking back against the wall. Once an Angel was Fallen they could never go back to heaven. Ever. A Fallen was easily identifiable by their wings, turned black instead of white. Each time an Angel sinned, each time they were debouched, a feather turned black. Once they were all changed, that was it.

But the more time passed, the hungrier and thirstier and more miserable Castiel became. Every day Dean would come back and repeat his offer, though he'd sit and talk for a while before leaving with the food. Eventually a combination of curiosity, hunger, and desolation had made him give in. Besides, Knight of hell or no Dean wasn't that bad. If he was going to become a debauched mate to a Demon, why not him?

So the next time Dean came back, Castiel had given in. He'd gotten his underwear ripped off and his virginity torn from his fingers. Then when he was recovering, still limp and breathless from his first ever round of mind-blowing sex, Dean had propped him up on his rag bed and fed him all the food he could eat, tipping the goblet down his throat until he'd drunk his fill.

Aside from the food, that had set the standard. Apparently things like good food were reserved for obedient mates, not Angels being brought to a Demon's level, but Dean did smuggle him treats sometimes. PB&J's were among his favorites. Every day the Alpha would bring him food, and at least once a day Castiel would get himself fucked against some flat surface or another. Sometimes on the rag bed, sometimes up against the wall. Every time he had an orgasm with the Demon another feather turned black, the change working its way down his wings. Sometimes Dean would mix it up a little, getting him drunk instead. Each time with a different type of alcohol. Castiel was partial to wine and vodka. Every time he woke up with a hangover, at least one more feather had changed. Dean had given him drugs a few times too, but he was less fond of those, though Castiel had enjoyed the experiences. Ecstasy had been interesting, LSD had been quite liberating, but the cannabis was his favorite.

However long Castiel had been here, he now had one feather left. He'd woken up one morning and realized that, over a week ago now. That day when Dean had come in Castiel hadn't let the Demon lay a finger on him, which had confused and annoyed him. The Angel had yelled for him to go away, refusing to listen to him, withdrawing into a corner with his hands over his ears.

Reverting to their first pattern, the Alpha would try to reason with him, offer him food, but eventually leave.

Today was the most recent of those days, but each day Castiel felt weaker, in more ways than one. His mistake had been giving in to begin with. He genuinely liked Dean, more than anyone else. He was afraid to admit he legitimately loved the Demon. To have the Alpha alternate between pleading, cajoling, negotiating...it was wearing him down as much as the hunger and thirst. Worse, he missed the sex too. Missed being kissed by soft, self-assured lips, missed clinging to broad shoulders, missed callused hands on bare flesh, even missed the looming membrane wings that the Demon would spread instinctively, protectively, whether they were making love or fucking. He missed having someone to talk to, missed having someone who would listen to him even though he was just an Omega, missed having someone who could make him laugh, make him think, make him angry and sad and happy and confused and...he missed Dean.

The Demon was kicking the door shut, as was his habit. Setting down the tray, coming to stand next to the huddling Angel. "Hey. How you holding up?"

Castiel didn't say anything. No protests, no comments, no yells to be left alone. He drew his limbs in tighter, pressing his wings firmly against his back, not lifting his head.

"Come on, Cas, look at me," Dean coaxed, bending down to nudge him.

The Omega waited until he'd dropped into a tailor's seat with a sigh, slowly lifting his face to stare at the Alpha. Dean was blurrier than he thought he'd be. He blinked a few times and his vision cleared, just in time to see the worried look creasing Dean's face.

"What's wrong?" He reached out, pressing a palm to his cheek. "Talk to me, Cas."

Castiel bit his lip, then made the mistake of meeting intent green eyes. He might have maintained his silence, but he was weakening. Those eyes, the ones he'd gazed into as he'd had his first climax with a partner, the ones that crinkled if the Omega made him laugh or narrowed if they argued, were what did him in.

"I don't...I don't want to be a Fallen, Dean," he whispered at last.

Evergreen eyes softened in the dim light. The Demon sighed, sitting back. "Right. Look, uh, you know they'll never take you back even if you weren't Fallen, right? We talked about this, Cas, even one black feather and you're an outcast. You don't gatta be a Fallen before they start treating you like shit."

"I know that, but..." He couldn't come up with a reasonable defense. It was a part of his old life he clung to, a part he knew very well he couldn't go back to. He'd been an Angel for so long, had had that way of life for so long, it wasn't easy to give up. Even as Dean coaxed him, day in and day out, a part of him clung to his last, lone white feather. The meager remaining tie to heaven.

Dean reached around, lightly stroking the black feathers at the top of Castiel's wings, the ones just visible behind his shoulders. The Omega flinched, then slumped, head bowed. He loved it when Dean touched his wings, fingers preening his feathers, more than once the Alpha had chuckled as he'd been reduced to practically purring in delight.

"You ain't the first, you know."

Castiel's head snapped up, staring at the Demon. "What? Who? You never mentioned this before."

"I was gonna surprise you, Cas. There are Angels down here, Fallen. Mostly Omegas and Betas. I asked around, found a few you might know. Balthazar. Anna. Gabriel."

"Gabriel?" Castiel repeated in disbelief. "The archangel? But they said he disappeared."

"Yeah, straight into hell. He's my brother's mate these days. They're all really eager to see you, but it's the rules. No Angels out of chains unless they're Fallen, can't have you running back to heaven."

The Omega slumped again, turning away. They'd been over this before. He knew the rules as well as Dean.

"Still don't know what's so awesome about heaven. We haven't got half as many rules, you're not allowed to do anything fun, and they turn on their own as soon as you stick a toe out of line. Think about it Cas, be reasonable." He leaned in, gently kissing his cheek. "You can go wherever you want, earth or hell, no one will dare touch you again. You'll be at the top of the food chain with me, a big ass room with plenty of space for a bunch of books and food and whatever else you want. No one will look down on you for enjoying something or liking something that's a little off, no one will ever ridicule you for choosing a life you enjoy. And..." Dean hesitated, clearing his throat. In a gruffer tone he added, "You'll have me. That counts for something too, right? This might be hell but we've got standards. I'll treat you right, you know that, and there'll never be anybody else."

Castiel closed his eyes slowly. Yes, that counted. That counted for a lot. The entire setup of hell wouldn't be tempting unless he was already Fallen, but if you threw a loving, faithful mate into the mix? It changed things, though he knew heaven would banish him for even thinking as much considering the mate in question was a Demon.

The Angel mumbled something, though it came out too garbled to really make out.

"What?"

Taking a deep breath, Castiel raised his eyes to meet Dean's. "Debauch me," he stated, clearly this time.

Dean's eyes darkened. He tangled a hand in the Angel's hair, yanking him into a hungry kiss. Castiel melted against him, uncurling his body so he could scoot closer, fisting his hands in Dean's shirt and gasping as he was pulled bodily into the Demon's lap. He hooked his legs around the Alpha's waist, head falling back, wings flaring wide and flat and limp in submission as Dean's loomed over them both. Tears welled in his eyes, but his lover kissed them away, rasping words of both tenderness and lust.

Castiel yelped when Dean lurched to his feet, something no human could have ever managed, clutching the Demon's shoulders to keep from falling. His back hit the damp wall, and the Omega hurriedly hooked his legs around Dean's waist. This new position made it easier for the Alpha to shove his shift up around his waist, out of the way, before fumbling with his own pants.

"Sure you want it like this?" the Demon rasped, gripping his hips firmly.

"Yes," breathed the Angel. "If you're going to make me a Fallen, might as well do it in an appropriate fashion. But could we make love on that big bed later?"

"Whatever you want, Cas. Anything you want."

The Angel's head fell back, a soft cry escaping his lips as his lover pushed into him. He clung all the tighter to Dean, breath hitching, head falling forward. A growl thrummed in the Demon's throat, capturing his mouth in a dominating kiss as he kept Castiel's hips pinned to the wall so he could thrust at his leisure. Though perhaps 'leisure' wasn't the best word considering in this state Dean only went slow if it was to torment. After the first few strokes he moved to a taunting pace, lips curling up into a smile as he pressed them to the Angel's throat as he whined.

"Dean, Dean please," the Omega whimpered.

"What 'cha want, Cas?" he rasped, tone almost innocent.

"Fuck me, Alpha, please- oh Father please fuck me, fuck me, Dean please..."

He cried out when his lover complied. A tormenting pace became forceful, each thrust slamming home and brushing his prostate in the process. Castiel turned his head, gasping out panted breaths, eyes locking onto the flight feather at the far tip of his right wing. It wasn't snow white anymore, not completely. Gray was starting to leach into it.

Instead of guilt, Castiel felt a surge of defiance. He hooked one hand around Dean's neck, digging his fingers into a shoulder blade while the other fisted in the Demon's short hair. The Omega attacked his lover's mouth, earning a surprised grunt from Dean, though he didn't seem upset by this.

"Atta boy, babe," the Demon rumbled between demanding kisses. "Take what you want."

"Want you," the Angel gasped.

They didn't talk much after that, not really. Castiel's ears were full of skin and feathers on stone, the smack of flesh on flesh, breath rasping through both their lips, growls and grunts in the Demon's throat, whimpers and gasps in his own. By this stage in their relationship Dean knew Castiel's body as well as the Angel knew his. It became almost competitive, each trying to get the other over the edge first. As usual Dean won that race, but it was a close thing. He snarled in climax before Castiel's scream had faded.

The Omega turned just in time to see his last white feather disappear under a wash of black. Maybe he would feel bad later, but he was still at the peak of an orgasm. He felt way too good to feel guilty.

Cracking a somewhat loopy smile, Castiel took his lover's face in his hands and kissed him. He kissed him long and slow and deep, taking his sweet time. He was so busy kissing the Demon he didn't notice one of Dean's hands had slid free, leaving the support of the Angel to his free arm and the wall. Castiel had just come up for air when something cold and hard clamped over his neck, clicking into place.

Jerking away, stunned, Castiel grabbed at his neck. His fingers met a silvery collar, cool and hard and unwavering under his attempts to rip it off. No, not...he knew what it was, but he had no idea Dean had one or that he'd use it. An Angel blade melted down to make a collar, one that would bind one of their kind even if they were Fallen. Unless Dean decided to remove it, he was forever bound to the Demon.

"What have you done?" he whispered, horrified.

"Hey, don't look at me like that," Dean scolded, sliding out of him. He gently lowered the stunned Angel to his bed of rags, sitting next to him and looking completely unrepentant. "Humans have these things too, you know that. I just made one for you."

"I know humans have them, but I don't understand why you would put one on me," the Angel protested, yanking at the thing with both hands.

"Hey, hey, easy Cas, easy." Dean caught his wrists, holding them in one hand and gripping his chin with the other, dragging the Omega's gaze up to meet his own. "I'm sorry I didn't mention it sooner, but you weren't exactly enthusiastic as it was. Yeah your wings are done all the way through, but without this it'll be a free-for-all. Remember what went on outside that door when you first got here? It sounded way better than it actually was."

Castiel hesitated. "So this is meant to protect me?" he asked, not convinced and still shaken. "I'm not a human." The protest was weak even in his own ears.

"No, you're an Angel Omega in hell. You're a real commodity, Cas, and I'd rather it be clear you're off the market." Dean pressed a kiss to the side of his neck, then his jaw. "It ain't coming off. You're mine."

The next kiss went on the Omega's lips. Castiel hesitated, then relaxed. Dean was right and he knew it. He just wasn't used to being...marked. Then again, he kind of liked the idea. If nothing else, hell would be far less boring than heaven had been.

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