With a Whimper

Summary: What if Castiel hadn't been able to stop himself and Dean was hiding a terrible secret?

Rating: NC-17

Pairing: Dean/Castiel.

Warning: Dark theme, violence, language, death. Basically everything needed for a well balanced episode of Supernatural.

A/N: This story follows the same basic plot line of season 8, the only change being that Dean saw Cass before he came back completely brainwashed and that this is an Alpha/Omega AU.

A pained whimper ripped from Dean's split lips when Castiel's fist slammed mercilessly across his battered and bloody face. Castiel's expressionless eyes bore into Dean's as he silently pummeled him to a pulp.

"Cass, please." He croaked out, blood oozing from his split, bruised lips. The pain in his body was brilliant, but the pain in his soul was beyond description.

Dean wasn't going to lie, the fact that Cas, the he'd ever allowed himself to trust and love aside from his brother, father, and Bobby, is currently beating him to death is a hard pill to swallow.

Castiel didn't respond, simply stared down at him with dull, lifeless eyes that were so different from the bright, expressive ones he'd become used to.

"T-This isn't you Cass, fight- guh!" Dean didn't get to finish his plea before Castiel's punishing fist struck across his bruised flesh again. The white hot flash of pain exploded throughout his skull.

The blood was flowing quicker now and Dean felt his consciousness start to flicker in and out. He had to figure out something to stop Castiel quick before he killed him and-

His brain stuttered on the thought, flat out denying him the right to finish that thought. As Castiel's fist wound back to strike again Dean tensed in preparation.

Dean found himself unable to stop the onslaught of sudden memories of happier times as Castiel's fist started to swing towards him again.

Squeezing his black eyes shut, a single tear streaked down his bruised cheeks as the images flashed before his eyes.

Four Weeks Prior

"Hello Dean." A voice sounded a bit hesitantly from above him.

Dean had been sitting on his bed, polishing his guns when the angel appeared. Head shooting up at the sound, Dean's eyes widened with shock at the sight in front of him.

"C-Cass? Is that you?" He rasped out uncertainly.

Giving him a small nod, the barest hint of a smile curved the sides of the angel's chapped lips.

"Yes Dean, it is." A somber expression overrode his previous one. "Please forgive me for being gone so long Dean. The recent issue with Samandriel-" Castiel faltered a little but continued on. "- it, uh, it left Heaven in a state of disarray. Caught up in the commotion I lost track of how long I was gone for."

Dean just continued to stare at Castiel in a mixture of disbelief, anger, and relief before he abruptly dropped the gun on the ground, stood up and pulled the angel into a bear hug.

"Fuck Cass, I've missed you like hell." He croaked out, unable to repress his basic, hidden omega desire to bathe himself in his alpha's scent as he rubbed his face tersely into Castiel's neck.

"I've missed you greatly as well Dean." Castiel said honestly, hand coming up to cup the back of his neck.

Being an angel, Castiel obviously didn't fall into the same perimeters as most alphas, but Jimmy Novak himself had been one.

Because of this Dean had watched as slowly, year after year Castiel delve deeper into his vessels root instincts and started displaying typical alpha tendencies.

This became most obvious when Dean had more or less "officially" become his omega shortly after their return from Purgatory.

Emotions and hormones running high Castiel had all but dragged Dean to his bed while Sam was off doing research and mated him withing an inch of his life.

Dean's omega status had always been a dirty little secret that he went to extreme lengths to hide, even from Sam. He wasn't proud about lying to his brother, especially after all they'd been through together.

One may think that after literally being to hell and back that he'd have managed to put shit like that into perspective.

Well, they'd think wrong.

To be fair, he'd been doing this for a long time so keeping this secret had become second nature. Dean had been using suppressants provided to him by his father during his teen years to control the heat's he got every three months, along with diminishing his natural omega pheromones since he was thirteen.

In an alphas and betas world omegas were treated like second class citizen. Even at the young age of thirteen Dean knew that to survive not only as a hunter but as a normal person, he'd need to eradicate any indication of his omega status.

Shaking away the memories, he smiled half-heatedly when Castiel, giving into his alpha instinct to in return coat his omega in his scent, started to affectionately rub his face against the side of Dean's.

"Wanting to make up for lost time Cass?" He purred out seductively into the angel's ear.

Castiel growled low in his throat at his words, hand tightening on the back of his neck.

"You haven't the faintest idea of how much I want that Dean." Castiel murmured and started to kiss down the column of his neck.

Shivering in his arms, Dean moaned softly at the sensation he'd longed to feel for weeks.

"Cass." He panted out a little desperately when suddenly he was being lifted up off the ground and carried towards his bead. He squawked in shock and indignation but didn't fight the angel as he was manhandled onto the bed.

"Give a guy a little warning next time, okay Cass?" He grumbled as the angel tore off his clothes as well as his own.

Castiel didn't respond verbally, giving Dean a grunt of acknowledgment before tearing off his boxers.

The fact that he was already soaking wet from just the thought of Castiel knotting him drove him even crazier, and with a desperate whine of need he arched up into his alpha.

"F-Fuck Cass, no foreplay, need your knot." Dean groaned out.

Castiel swore in a language Dean wasn't familiar with before looping his arms under Dean's knees and pushing them wayward.

Dean whined, the noise high pitched and totally manly as he felt Castiel's hard, hot erection rub up against the cleft of his soaked ass.

"Is this what you want Dean?" Castiel purred out roughly, voice filled with lust. "Do you want me to breed you full of my knot?"

"Yes, fuckin' hell, yes! Please!" Dean cried.

"Mine!" Castiel snarled possessively and thrust his entire throbbing length into Dean's sopping wet hole.

Dean arched violently against the mattress and yowled, thrashing wilding on the end of Castiel's cock. "Oh, fuck CASS!" He wailed, eyes screwing shut in bliss.

"You're mine Dean! My omega!" Castiel snarled out before his hips started to fuck his dick furiously into Dean's hole.

Dean wrapped his arms, clutching fruitlessly onto the angel's sweat-slick shoulders as he pounded into him. Weeks of sexual and emotional frustration poured out of them both, leaving them slaves to their basic instincts.

Dean felt the base of Castiel's cock start to swell, catching on the rim of his raw hole as he trust inside of him.

"Oh, God Cass, knot me. Knot me Cass –fuck- please!"

With a loud snarl Castiel pounded into Dean five more times and with a loud shout slammed the engorged knot fully into Dean's ass, come spewing out and filling him up.

Dean came with a loud wail quickly after that, arching up into Castiel as his come splattered across the angel's stomach.

Castiel went lax on top of Dean for moment before rolling over onto his back, bringing Dean with him so that he could rest on his chest.

"Rest for now Dean. I will clean you and the bed up before Sam returns." Castiel murmured out, voice still rougher then usual. Resting his head tiredly on his chest, Dean yawned loudly and nodded lazily.

Even if it was just for a moment, everything in his life was awesome as he slowly drifted off to sleep, warm and content with his alpha in his own brand new bed.

That is, until he woke up clean but sore with Castiel no where in sight. Nor would he be for the next month.

That had sucked pretty damn bad, but not nearly as much as when he learned three weeks later that his omega suppressants had unexpectedly failed and that he was now, in fact, pregnant with Castiel's baby.

Shit.

The powerful blow knocked him swiftly out of the flashback, undoubtedly strong enough to have thrown him into the wall had Castiel not been gripping tightly onto his collar.

Dean felt the life slowly ebbing out of him, too much blood oozing out of him way too fast. He felt his eyes start to drop with exhaustion but the sight of a Castiel's blade slowly being rose over his head to strike the killing blow snapped him back to reality.

Hand shooting out in a last burst of strength, he grabbed tightly on to the angels trench coat, tears streaming freely down his face now.

"Alpha!" He sobbed out, the word sounding as if it had been literally torn from his throat. Large globs of blood spewed out from his lips, showing clearly how serious his internal injuries were.

The angel froze dead in his tracks, but didn't drop the angelic blade.

Trembling helplessly Dean swayed a little before collapses against Castiel, burying his face in his abdomen and unable to hold himself up any longer. Despite this his hand never released its tight grip on the angel's trench coat.

"I l-love you, so much Cass." He croaked, voice resigned to a fate he'd never thought he'd meet. "Were the best alpha I… I 'coulda ever hoped for." Blinking back tears, he felt his eyes slide upwards to meet the angels.

"I f-forgive you Cass." Dean whispered out softly.

With the last ounce of his will he closed his eyes and sent his beautiful angelic alpha one last prayer. A prayer filled with visions of pointless but none the less wonderful dreams of them raising their baby in a stupid little suburb in some safe, unassuming little town.

Of a life where Sam was happy with that Amelia girl and the only issues he and Castiel needed to concern themselves with was who's turn it was to change the babies diaper.

A loud, abrupt gasp erupted from above him, filled with horror and anguish. The loud, piercing sound of the blade collapsing next to him would have caused him to flinch, but he was to far gone to care.

"B-Bet they woulda' had your... your eyes." He slurred out, one last lone tear streaking down his shattered cheek bone before his world collapsed into endless darkness.

He didn't even have to hear the broken wail of, "Oh, God Dean NO!" pierce through the silent crypt as he faded into nothingness.

Thank God for small mercies.

Naomi watched with a small, very satisfied smile as the life slipped out of Dean's limp body.

Castiel hadn't even needed to sully his angelic blade with the humans disgusting blood. It appears that the savage beating she'd had Castiel inflict on him did the trick just as well as any blade.

She felt a fleeting sensation of sympathy as she watched Castiel collapse to his knees in front of Dean and sob, clutching his fallen omega to his chest as he attempted to pump life back into the dead body via his grace.

As if Naomi would allow Castiel to waste his grace on such a frivolous task. She'd made sure to cut off all of Castiel's healing abilities as soon as they'd arrived in Lucifer's crypt.

Naomi smirked cruelly at the brightly glowing jar that rested on her desk, the blue light inside seeming to fight futilely against it's restraints.

She'd make sure that Dean Winchesters soul got what was coming to it for all the grief he'd cost not only Castiel but all of Heaven as well.

It wasn't difficult in the least to retrieve the Angel tablet. She'd easily managed to slip in and out without attracting any attention.

Castiel had simply remained crying hopelessly into Dean's neck, all other duties completely forgotten.

Naomi shook her head and watched the scene with distaste. Why Castiel would allow himself to develop such a sinful relationship with a Winchester of all people was beyond her.

It was clear from her brother's reaction that Castiel would not be joining Naomi back in Heaven like she'd hoped originally.

Looking back down at the tablet in her arms, she smiled happily.

Well, at least she'd managed to retrieve this before the Winchesters or Crowley made off with it, and that was all that really mattered.

END (?)

A/N: Wow, I haven't posted anything on this account in forever, lol. I have no fricken clue where this came from. Clearly I'm in some sort of bad place right now, lol. I'm a little conflicted on whether or not I should continue this or not with a sequel detailing Castiel's reaction to having killed Dean and how Sam reacts as well. What do you guys think? Should I even bother or should I just leave it as a depressing snuff fic? All comments and criticism are greatly appreciated, and thank you for taking the time to read!