There is an established relationship before the mark of Cain.

Sam/Dean-Wincest. Demon Dean and blood lusting Sam.

Sam entered Deans bedroom and sat down beside him to see his brother still lying there, motionless, eyes sealed shut.

"Dean..Please...Open your eyes Dean" Sam said between sobs. Tears fell from his eyes and dripped onto Deans arm. Sam gripped his brothers hand and squeezed as hard as he could, hoping for some kind of reaction. Dean remained unmoving. Sam let his hand fall as he slowly stood from the side of the bed.

"Sammy..." A faint whisper came from Deans lips as Sam was about to exit the room.

Sam spun around on his heals so fast he almost lost his balance.

"Dean?..." He asked cautiously, still not sure if what he heard had been in his head or not.

"Sam...help" Sam had definitely seen his brothers lips move that time. Gently walking towards the bed Sam held out his hand. As he reached the bedside he realised that his brothers eyes were still shut.

"Dean, Open your eyes Dean" Sam cooed softly into Deans ear stroking his brothers hand.

"Sam...I can't..."

"Why?" Sam asked voice thick with worry.

"I dunno Sammy."

"Ok, don't panic. I can help you" Sam leaned his head in to his brother. He placed his lips on his brothers but quickly pulled away when he felt Dean flinch.

"Sammy, I'm sorry I just wasn't expecting that" Dean said turning his head away.

"Come on big brother, open your eyes, please" Sam pleaded.

Dean slowly turned his head so that he was facing his younger brother, his eyes shot open and stared directly at Sam.

"Oh my god.." Sam exclaimed as he stood up and took a few steps backwards.

"Sam please, don't be scared" Dean dropped the first blade from his hand, forgetting that he had been holding it in the first place.

Sam took a step towards his brother reaching his hand out and grabbing the side of his jeans and pulling him flush against himself.

"You're alive" Sam cried onto Deans shoulder.

Dean smiled and gently let his fingers play with the curls that had started to form around the base of Sams neck.

"I'm here Sammy. Told you I'm not going anywhere." Dean whispered to Sam.

Sam lifted his head from Deans shoulder and looked into his eyes, his now demon eyes.

"God Dean" Sam all but whined.

"What Sammy?" Dean asked

"You're eyes...they...they're fucking hot" Sam breathed, not able to meet his brothers gaze completely.

Dean gave a soft giggle and slowly moved his hands to grip Sams hips. He manoeuvre him so that Sams knees hit the back of the bed.

"Dean we really shouldn't do this yet"

"Why Sammy? You scared you're gonna love fucking your big brother even more with my eyes like this?" Dean whispered

"No...we shouldn't..." Sam resisted, he suddenly felt Dean pull away from him and out of the corner of his eye he saw him walk over to the other side of the room, where Sams duffel bag was thrown onto the floor.

"Dean? What are you doing?" Sam asked turning his whole body around to see why Dean was rooting around the bag.

Dean continued searching through Sams bag ignoring his brothers words. He took a lot of things out of the bag that he wasn't looking for, books of lore, Sams laptop until he came across the one item he had hoped was still in the bag.

"Oh Sammy, you will like what I'm gonna do for you" Dean voice had suddenly gone from comforting big brother to something vicious and laced with cruel intentions.

Sams heart skipped a beat but not in the usual way it does around his big brother. Sams nostrils suddenly flared and his heart sank to the pit of his stomach.

"Recognise this smell Sammy?" Dean asked adding a chuckle.

"Dean what the hell do you think you're doing?" Sam took back from where he was standing and stumbled over the bedside table behind him.

He hit the floor with a bang and that was when Dean turned around holding Sams knife with his hand gripping the blade. Sam could see little droplets of blood falling from the underside of Deans palm onto the old motel carpet. The scent was so familiar, too familiar. Sam tried to hold his breath for as long as possible.

"Can't stop breathing forever baby brother, gotta breath it in sometime" Dean chucked taking another step towards Sam who was still sat on the floor holding his breath. Sam shook his head and turned his gaze away so he didn't see the continuous stream of blood dropping and Dean walked closer to him. Dean however was right, Sam couldn't hold his breath for much longer no matter how much he wanted to. With as much reluctance as he could muster Sam took a big breath through his mouth, hoping that would stop most of the smell getting to him. He was mistaken.

"Oh god."

"That's right Sammy you want this, don't you" Dean said menacingly whilst crouching down to Sams level and waving the bloody hand in his face.

The instinct inside Sam that had been suppressed for so long told him to reach out and grab Deans hand. He closed his eyes and tried to roll onto his stomach to completely hide from Deans tempting hand.

"Sammy, Sammy, Sammy why do you insist on disobeying your older brother. You know I'm only trying to help you right" Dean said to Sams back

"How is this helping me? Getting me back on Demon blood. That's just sick Dean!" Sam shouted at the ground, still not wanting to face Dean.

"You won't be saying that soon baby brother" Dean said gently rubbing Sams back.

Sam could feel his will power fading, quicker and quicker by the second. He knew that he would give into Dean as soon as all of his resolve had faded. He was so scared. Sam felt a silent tear run down his face and onto the concrete floor of the bunker.

"Dean...Please...Don't do this to me" Sam begged with the final ounce of hope he had left.

"Come on Sammy, you used to love this stuff. Just one little drop that's all it'll take."

Sam lifted his head from where it had been resting on his arms and looked up at Dean, his resolve broke. He latched onto Deans hand and quickly lapped up the droplets of blood that were still spilling out.

"Oh god, that's right Sammy, drink" Deans eyes that had been hazel whilst trying to convince Sam to drink had now turned as black as coal. Dean threw his head back and let out a glutinous moan.

Sam hears Dean moan and looks up at him, he stops drinking and wipes the excess blood from around his lips and chin. Sam sat back and just stared at Dean for a couple of minutes before speaking.

"You're right you know"

"About what baby brother" Dean replied getting incredibly close to Sams face, smelling his blood on Sams plump, red, kissable lips.

"All it took was one drop" Sams eyes lit up and a devilish grip started to creap it's way onto his face.

"Keep talkin' Sammy" Dean said less than an inch from Sams lips. Sam didn't continue to speak though, Sam rose from his position grabbed Dean by his upper arms and rammed him into the wall between Deans bed and the adjoining wall, Sam attacked Deans mouth with such force Dean thought his head may go through the wall into the next room. Dean knew that if he really wanted he could have Sam through the wall and begging for mercy, but even as a newly formed Demon he like being slightly submissive. Sam continued kissing his brother but his hands started to travel south and grabbed Deans thighs and lifted him up to wrap his legs around his own waist. Sam moved to kiss Deans neck and started peppering it with soft light kisses.

"Fuck Sammy, harder please. Can't take this soft crap"

"If it's hard you want, it's hard you're gonna fucking get!" Sam immediately bit his brothers neck and nearly drew blood.

Sam dropped Dean so his feet hit the floor with a thud. Sams hand swung from behind him and came into contact with the front of Deans jeans giving him a firm squeeze drawing out a ragged moan from his older brother. Grabbing the top of Deans jeans Sam ripped them clean from his body. At that moment Dean wanted to push his little brother onto the bed and ride him dry but it took all his willpower to stay where he was.

"Like this don't you Dean? Even as a demon you want me to fuck you into this wall" Sam growled as he turned his brother around and ground his own erection against his ass.

"Fuck Sammy! Do something now!" Dean almost begged.

"Aww Dean do you want my dick burried in your tight hole do you" Sam taunted while reaching around and trying to grab his brother rock hard dick.

"That's it!" Dean pushed off the wall grabbed Sam by the shoulders and threw him onto the motel bed, his full body weight on top of him.

"You were taking too long and I need this now, been too fucking long" Dean said making his way down Sams lithe body to the zipper on his jeans which he made short work of.

"Fuck Dean!" Sam was lifted up and turned around with his ass in the air. Dean was already hard from Sams grinding and dirty talk.

"Dean...lube?" Sam asked.

"Do you really deserve lube Sam? Have you earned it?"

"De..please. Fucking need you now!"

Hearing Sam say his nickname was all it took for Dean to spring into action. He pulled out a small tube of lube from the bedside table which was only barely within reach. He squirted it onto his hand and rubbed it onto his dick. He didn't want there to be too much lube, he wanted Sam to be able to feel it the next morning. He lined himself up with Sams eagerly awaiting hole.

"Christ Sam. should see yourself right now. So open and fuckable" Dean pushed into Sam with a considerable amount of force. He set a harsh pace that he thought Sam may object to.

"That all you got? Thought demons were meant to be strong?" Sam taunted hoping to rile his brother into going faster. It worked. Deans hips started pistoning in and out of Sam.

"FUCK! Oh god Dean"

After a few minutes of abusing Sams hole, Dean stopped and leant down close to his ear.

"Turn around, I wanna see your face when you come all over yourself"

Sam didn't even respond he turned around and looked into Deans black eyes. Dean lined up again and went straight back to what he had been doing. He could feel Sams hole getting tighter and tighter, he knew Sam was close. Dean angled slightly and hit Sams prostate repeatedly for about one minute until Sam let out a scream of his brother's name and came all over his stomach. Dean soon followed suit and the two of them lay there soaked in sweat and come.

Sam suddenly got up from the bed, looked Dean eye to eye, drew his fist back and punched him so hard into the jaw that Dean flew backwards across the bedroom and hit the opposite wall. After collapsing in a heap on the floor Dean shot Sam a look that told Sam he better start talking right now. Deans lip started bleeding from where Sams knuckles had impacted with his skin.

Sams eyes went from narrowing with rage to a wide eyes stare when he saw blood dripping from Deans lip. Sam was so mad that his brother had done this to him. One little drop is all it took for Sam to want nothing more than Deans blood, all of the time.

"You did this to me, the one person I loved, I thought you wanted to protect me" Sams voice tried to sound upset but it failed him, Dean would tell how Sam was feeling at that moment. Dean slowly moved his tongue out and lapped at the cut on his lip. Sams dick started to stir again. He tried to stay rooted to the spot but his instincts were screaming at him to go to Dean and lick his lip. He launched himself at his brother who was still on the floor seductively nursing his split lip.

"Oh god Dean. Your blood, it does things...to me...oh fuck" Sam whimpered as his tongue reached out and licked his lip.

"What does it do Sammy?" Dean asked, knowing the answer already.

"It makes me want to fuck you and touch you everywhere and oh god Dean I need you so much"

"Take me Sammy...Baby boy" As soon as Sams nickname left Deans lips Sam attacked his mouth once again and shoved his tongue into his brothers mouth. He could still taste the blood on Deans tongue from where he had been licking it earlier. That drove him wild.

Sam had intended to get them both onto a bed before continuing his assault on his brothers body but he couldn't stop himself. He kept his lips moving on Deans and lowered himself so that he was now lying on top of his brother and Dean was flat on his back on the cold bedroom carpet.

"Oh Christ Sammy" Dean started bucking his hips up to meets Sams thrusts.

"I'm gonna fuck you so hard Dean, Gonna make you come screaming for me, and this time, I'm in control!" Sam said as he peppered kisses all over Deans body. He bit down gently on both of Deans hipbones. Sam turned his brother over so he was now on his stomach and Sam was rubbing his ass cheeks and sliding a finger over his begging hole.

"Want this Dean? Want me inside you?"

"Please Sammy need you now. Fuck me!" Dean all but screamed at his baby brother.

"You asked for this" Without warning Sam shoved 3 fingers into Deans ass and started thrusting them in and out as fast as he could, Dean was still lubed up from Sams earlier torturous actions. Dean barely had time to catch his breath before he felt the intrusion.

"FUCK SAMMY!" Deans eyes still black squeezed shut at the mixture of pleasure and pain he was feeling at that moment.

Sam had no intention of going easy on him, no, Sam had other plans. He removed his fingers which earned a sigh from Dean. His fingers were soon replaced by his dick and Sam set a rapid pace. While ramming into his brothers ass as fast as he could Sam leaned down and sunk his teeth into the back of Deans neck drawing blood and smearing his face into it while licking as much as he could get into his mouth at once.

"Dean...oh god you taste and feel so fucking good"

"Take all you want Sammy!" Dean moaned.

Sam could feel the fire in the pit of his stomach building. He sped up and Dean knew he was close himself.

"Come for me Sammy, Come inside me" Dean begged. He reached around and started jacking himself off and before he knew it he was coming at the same time as Sam.

"Dean oh fuck, Dean, OH GOD!" Sam came with a scream and grabbed onto Deans shoulder once more.

Sam rolled off Dean and lay on his back on the floor breathing heavily. Dean rolled so that he was leaning on one elbow.

"Sammy promise me something, promise that this won't change us anymore" Dean said pointing to his shoulder bite and his eyes.

"Nothing is ever gonna change again De I promise you that"

"Good because I...I love you Sammy"

"That's good, ready for round 3?" Sam winked at his brother

"I'm always ready"

-Fin-