A/N: This fic contains Alpha/Beta/Omega dynamics. This includes mpreg, self-lubrication, and knotting. If you're not into that kinky shit, please don't read this. You will be thoroughly weirded out.

Characters: Endverse Cas, Endverse Dean, Risa

Pairing: Endverse Cas/Endverse Dean

Tags: ABO, Endverse (referring to the alternate universe in season 5 episode 4, "The End"), top Dean, bottom Cas, drug abuse, self-lubrication, knotting, mating bond, angst, breaking up, mating cycles/in heat, alpha Dean, omega Cas

Part 1: Heat
Part 2: Claim
Part 3: High
Part 4: Switch
Part 5: Loss

Dean has spent the last two weeks in a drunken haze. He's even resorted to some pain killers he found in their-in his bathroom, for when it gets really bad. Which is pretty often.

Castiel hasn't broken their mating bond yet. Dean doesn't know why; it's killing him, flaring up through his entire body whenever he sees the omega and burning him up from the inside out any time someone enters Cas' re-claimed cabin.

He doesn't smell like sex when Dean is close enough to him, just weed and alcohol and all of his dark emotions, but Dean is consumed with jealousy at all of the time Cas is spending with people who aren't him. He knows the kind of people who are spending hours in there. The cokeheads, the heroin addicts. And he knows Cas is indulging in more than his fair share; he's always in a haze or manic and on the last two missions he's been on he's acted reckless, careless, like he wants to die. Dean is haunted by the horrible thought that maybe he does.

Which makes Dean a danger on their missions because he's always getting distracted, searching for his former lover, feeling the constricting protectiveness through their bond and wishing he could just let go of Cas and sever it himself, but he can't. He isn't giving up hope, not yet.

Dean is taking his hourly walk around the cabins, completely not stalking Cas, when he smells it. The warm, sweet, irresistible scent of Castiel. In heat.

He's pissed at Cas, he resents him, but a mated omega going through a heat without their alpha can be agonizing. Dean can't let Cas go through that.

As he approaches he nearly collides with an alpha headed in the same direction, lust radiating off of him in waves. Dean stares directly into his eyes and snarls and the other man retreats quickly.

Dean breathes in a shaky breath as he reaches the beaded curtain in the doorway, cock pressing hard against his fly and he wants nothing more than to be in the wet heat of his omega.

He hears moans coming from inside, sounds of discomfort and barely satisfying pleasure, and then his name groaned out. The alpha was going to knock, to be civil and ask to come in, but a primal urge takes over him and he knocks the beads out of his way and rushes inside.

Cas is lying on his back on his bed, flushed and sweaty and shaky, fucking himself with a knotted dildo. His eyes fly open and he inhales deeply, scenting the alpha, coming all over his stomach. The sight makes Dean's dick throb and he moves closer, but Castiel's briefly satiated expression turns cold.

"You can't just barge in here like you own the place."

The alpha is far too aroused to be ashamed and watches as Cas pulls the slick toy out of himself and hops off the bed, storming towards him, unable to walk straight. It could be the heat, or drugs, or both. The closer he gets, the more Dean can tell he's in bad condition.

"You're suffering, Cas." He lifts a hand to the omega's forehead and keeps it there for a moment until he former lover flinches away. "You're burning up, you have tremors, and you smell like vomit."

"I can handle it."

Dean feels frustration rise at Castiel's stubbornness, at the harsh way he is treating the person whose heart he just broke.

"This would be a lot easier for you if you would just break the damn bond," he spits out, and Cas recoils.

"Do you want me to?"

Dean sees that Cas is hard again and he moves instinctively moves closer until he can feel the omega's fever radiating through his clothes, the the scent tantalizing. The bond between them is singing, taunting him, making him emotional.

"Of course not. But if you're going to leave me, be a fucking man and finish the job."

Cas looks up at him, eyes glassy and unfocused, and reaches his shaky hands up to Dean's jacket collar, clenching hard. The alpha wonders what he's taken. His temper simmers down a little at the feeling of him trembling, the smell of his sweat and desperation.

"You're a mess, baby. Let me help you."

Castiel's demeanor changes in a flash and he pushes Dean away.

"Then break the bond yourself."

Cas turns around and starts walking toward the bed when Dean comes up behind him and grabs his arms hard, pressing himself against the omega's back and aching as he feels the warm slick soaking through the front of his jeans. Castiel whines and grinds back against him.

"Not gonna happen," Dean snarls, pushing Cas toward the bed.

"Then do something you're good at and fuck me, I'm sure you've had lots of practice since we've been apart."

Dean knows Cas is just trying to get under his skin, to push him away and make Dean lean toward his twisted belief that the omega isn't good enough for Dean. He knows he doesn't mean it, but it still infuriates him. He's trying to provide for the person who abandoned him but still but won't cut that last cord of hope, and he's being treated like some asshole who sleeps around just weeks after being left by his mate. He doesn't want anyone else, he wants Cas , and he's going to have him.

He makes quick work of undressing himself as the omega lies down on his stomach on the bed, grasping at the sheets and grinding down into the mattress.

As soon as Dean is undressed he's on top of Cas, sliding into his slick entrance with a hard thrust and pinning his hands over his head roughly.

It's been a month since he's been inside his former mate, he's been yearning for so long. The last time they had sex, before the miscarriage, it was gentle, passionate; now it's rough and tense and Dean is so full of anger and hurt as he thrusts in and out of the omega sharply. He's not hurting him, Dean would never hurt him, it's just all he can offer right now, and probably all that Cas would accept.

"Dean, alpha," Castiel moans, and Dean wonders if he's said anyone else's name like that since he left. The thought makes him sick and he switches Cas' right hand over so that he's holding both wrists in his left and uses his right hand to grip Cas' hair and lift his face off the pillow to his own.

"Have you been with anyone else since me?"

The omega doesn't respond, just moans loudly when the alpha nails his prostate.

"Answer me," Dean growls.

Cas glares at him, a mix of anger and lust at his dominance, then looks away. "Not that it's any of your business, but no."

Dean slows down the movement of his hips, releasing Cas' hair and letting his head fall back down into the pillow because he can't look Cas in the eyes when he speaks next.

"Tell me you love me."

Dean buries his face in the omega's damp hair, smells the cocktail of sadness, anger, arousal, and then a sweet scent of something more gentle. He feels pathetic for asking that of Cas but he's desperate.

"Tell me you love me, Cas," he demands as he picks up his pace again, feeling the heat building in his groin, telling him he's close.

"Dean," the omega says weakly, and then he sniffles.

"Say it, goddamnit!" the alpha yells. "I need to hear it."

"I love you," Cas chokes out and Dean comes hard, feeling his omega shudder as he follows him. Hearing the words hurt him a lot more than it did comfort him, but he's glad Cas told him.

Dean collapses on top of him, kissing the back of his mate's head while Cas whispers, "I love you, I love you," over and over. He stops after a minute or so and reaches for a bottle of pills on the nightstand. It's Vicodin.

"Cas, don't."

The omega ignores him and shakes out two pills and dry swallows them.

"What else have you taken today?"

Castiel shrugs nonchalantly. "I shot up a few hours ago."

Dean grabs Cas by the shoulders and jostles him. "Damnit Cas, are you trying to stop your fucking heart?"

Dean's knot has gone down so he pulls out and rolls Cas over onto his back to face him.

"No, but I can't say I would particularly care if I did."

Dean is drowning in sorrow and hopelessness and wants nothing more in the world than to help Cas, but he has no idea how.

"Do you have any idea what that would do to me?"

"Yes. It would give you one less thing to worry about."

Dean's vision clouds and he punches the pillow just an inch from Cas' head, concerned by his delayed flinch.

"Tell me what to do, Cas. This is killing me."

"Stay away from me. Give up. Or I'll keep taking the life from you until there's nothing left. And you have so much to give. I just don't have the capacity to take it."

Dean's heart sinks, his stomach sinks, his whole insides feel like they're about to fall out. "What do you mean by that?"

The omega sighs and his eyes flutter closed. "Angels weren't programmed to deal with human emotions. Even the littlest ones scream at me, consume me."

"Then let me help you. I need you, I've always needed you."

Cas looks up at the headboard and tears well up in his eyes. "I'm so sorry, Dean."

And then something snaps inside of him, like a rubber band breaking, and Dean's heart is flooded with darkness, an empty gray isolation. Cas broke the bond.

"I'm so sorry, please forgive me," Castiel sobs as Dean pushes off of the bed and grabs his clothes.

"You know what made you different from the rest of your dickhead family? You had a heart."

Cas stares at him as he gets dressed, audibly crying, but Dean refuses to look at him. He struggles to put his clothes on-he's pretty sure his shirt is on backwards and his boxers are inside out-and then storms through the doorway. He gets tangled in the strings of beads and tears down the curtain in frustration, stomping on it for good measure.

He almost makes it to his cabin before collapsing to his knees, breaking down like he hadn't since he found out Sam became Lucifer's meatsuit. People are probably staring at him, their strong, fearless leader crying in the dirt, but Dean can't see any of them. He doesn't care.

He's not sure how much time passes before a small but strong frame lifts him up-an alpha, Risa-and drags him into his cabin.

She dumps him onto his bed and hands him a bottle of cheap whiskey.

"Pull yourself together, you're freaking everyone out," she scolds, crossing her arms.

Dean stares at the bottle and considers telling her, "Fuck it, you take over," because she's stronger than he is, and he's getting so tired, but when he looks up Risa is gone.

He gazes around his surroundings wearily, at the piles of pillows and blankets that make up the nest he never disassembled and he sees red. He starts frantically grabbing the linens and shredding them with his bare hands and when they're torn up and lying dirty on the floor he grabs Ruby's knife and begins stabbing into the pillows, sending feathers everywhere. When his bed is messy but basically back to normal he chugs some whiskey and lies down, instantly regretting his actions.

He should have kept the blankets and pillows that didn't smell like Cas.

Stay tuned for next instalment: Hope