Title: "The Sickness."
Description: Sam/Lucifer. Song fic for Disturbed's "Down With The Sickness."
Sam will do anything for his Master, Lucifer; drinking demon blood to become stronger for him, and even letting demons inside him.
Warnings: Mention of master/slave, some knife!kink, talk of Sam/Ruby, and blood-drinking.
Disclaimer: I own none of the characters mentioned in this fic, nor do I own the song it's based off of; I also make no money writing this, and just do it for fun.
Word count: 3,765.

Drowning deep in my sea of loathing,
Broken your servant I kneel.
(Will you give in to me?)
It seems what's left of my human side
Is slowly changing in me.
(Will you give in to me?)

Sam fell to his knees, gravel digging through the thin fabric of his jeans, hands splayed out in front of him as he panted hard. His entire body ached, and his head throbbed as he sat there, choking on some invisible mass in his throat. Throwing his head back, a black cloud of smoke ripped itself out of Sam's mouth, flying into the sky, then into the ground in front of it's host. He fell to the ground, body doubled over and face pressed against the damp gravel. He was tired of these demons invading his body, taking it for their own and making him their bitch. But Sam knew if he didn't do it, if he didn't allow those things inside him, he'd never be strong enough. And he needed to be stronger, his Master had said so.

Coughing, Sam pushed himself up immediately feeling his body for cuts - like he always did, and sighed in relief when he only found minor scrapes. He knew that if he had cuts, or wounds of any kind, Lucifer wouldn't be happy with him; he would treat him like his demons, instead of the human who he would one day inhabit. Sam smiled at that thought; his Master had always treated him better than any of his demons, even the A-list ones like Azazel and Alistair. Sam, who was a human, got special treatment, got to spend time with their Master, while every other demon got ignored, and rarely saw Lucifer.

"Sam." The familiar voice pulled Sam back from his thoughts and he turned his head, looking up the vessel that his Master was now using. Except, the vessel - Nick, his name had once been - was worn out, old, and falling apart. Sam knew it would be a matter of time before the demon would be in his body, and using him for his own bidding.

"Master," Sam scrambled back to his knees and dipped his head respectfully, like he was taught a year ago when Azazel brought him to Lucifer. He heard the low chuckle from his Master's vessel, felt his large hands on his shoulders, before he was being pulled up and off the ground.

"Sammy, Sammy.." Lucifer cooed, his hand lifted to trace Sam's jaw softly, which caused him to shut his eyes. "I see you're progressing well - you had one of Azazel's students inside of you, did you know that?" Sam nodded his head, opening his eyes, before locking them on Lucifer's blue eyes. The more Sam looked at his vessel's eyes, the more he could see his Master's true eye color coming out, and his heart thudded dully in his chest.

"Thank you, Master," he whispered softly, dropping his gaze to the ground beneath his feet. He always felt like he didn't deserve to look his Master in the eye, nor even speak directly to him. But when Sam felt a hot - not warm, but hotter than the fucking sun - hand on his chin, he pulled his gaze back to his Master, who was smiling at him.

"You're doing great, Sam," Lucifer whispered in Nick's voice, and Sam wondered how the words his Master said would sound in his own voice.

"You're getting stronger, and with the demon blood Ruby and Meg are supplying you.." Lucifer chuckled, his hand falling on Sam's neck, taking hold of it. "You'll be ready for me in no time." Sam smiled tentatively at his Master, feeling his cheeks burn hot as he stared into Lucifer's eyes.

"Thank you, Master," Sam whispered again as he swallowed hard against the searing heat emitting from Lucifer's hand. He wouldn't budge, though, because Sam loved when his Master touched him, reveled in the touch, the heat, and the softness of his vessel's skin.

"Ah, Sam," Lucifer sighed, tilting his head slightly, his mouth up-turned in a crooked smile. "You're becoming more and more like one of us, every day." Sam lived for praises like that - his human father, as Sam so lovingly called him, wasn't one for compliments, unless it was to his human brother, Dean. Sam mentally growled at himself for thinking about his 'human' family, and quickly pushed all the thoughts from his head. He was Lucifer's, and Lucifer's only - no one else could control him, or make him do the things his Master could.

"Go to your motel, Sam; Meg and Ruby will be there soon, to feed you." Lucifer chuckled and leaned in, brushing the bruised lips of his vessel against Sam's. Sam whimpered against them, his knees almost giving out, but he remained steady under his Master's hold. As soon as the lips were there, they were gone, along with Lucifer.

Looking at my own reflection
When suddenly it changes
Violently it changes (oh no)
There is no turning back now
You've woken up the demon in me

Sam walked into the motel room, stripping his jacket off and folding it in half, before placing it on the dresser. Since he'd been with Lucifer, Sam was even more meticulous than he was when he'd been with Dean; his things were in order, his room tidy and the bed made every morning. He also kept himself in top shape, only eating foods that were good for him, and full of protein, so he'd be physically strong enough for Lucifer.

Making his way through the hotel room, Sam made sure he had everything in order - checking his clothes, books, and various other items to make sure there hadn't been an intrusion. When he was satisfied that there was nothing out of place, Sam walked to the bathroom, flipping on the light as he shut the door behind him.

Sam's eyes went to the mirror, and he studied himself; running his fingers along the stubble that was on his jaw, wondering if his Master liked that or not. He shrugged and looked at his eyes, staring at them in the glass before they suddenly changed; going from the hazel color he'd always had, to yellow, red, then finally black. He couldn't see the color of his own eyes, but he found the black flattering, almost beautiful, and a nice change of pace.

Then, in the mirror, Sam watched his head snap back and forth, side to side, and suddenly his face was twisted. His upper lip was curled into a snarl, and he was grinning, fucking grinning, in a way he'd only see his Master grin. Sam closed his eyes, swallowing hard at the image in front of him, and then opened his eyes again, only to find a new, even more horrifying, scene.

It was him, or at least his body, standing above a man that looked like his brother - his human brother, the one he left behind for Lucifer, for the life he knew he'd always lead. There was blood on his suit, that was snow-white and perfect, and he was grinning down at the lifeless body at his feet. Sam shut his eyes again and turned, walking blindly out of the bathroom and opening his eyes, gaze falling upon Ruby and Meg.

They were two of Lucifer's favorite demons - Ruby had found Sam when Dean went to hell, and helped him get over it, subsequently getting him hooked on demon blood. Meg was the demon whore he and his family - Sam winced every time he thought about them - had killed, and sent back to Hell. Now they were his mentors, and the only two demons that would talk to him, even after knowing that he was Lucifer's favorite.

"Hungry, Sam?" Meg asked, grinning her stupid little half-smirk as she took a step toward the bed. Sam didn't like Meg - didn't before, sure as hell didn't now, but he liked Ruby. She was sweet, in that 'she's a demon, she can't be trusted' kind of way, and not to mention, she was aesthetically pleasing, unlike Meg.

"Can't I drink Ruby's blood?" Sam asked, sinking down into a chair and rolling his sleeves up, staring into Ruby's eyes. He heard both demons chuckle, and could feel Meg's eyes on him.

"This is because you have some kind of freak attraction to her, eh?" Meg asked, and Sam thought he heard jealousy in her voice and that made him smile. He turned his attention to Meg and rolled his eyes, splaying his hands.

"Maybe I just think her blood is more potent, and that it makes me stronger, you ever think of that?" He shot a hard glance at the demon when she opened her mouth, and she quickly shut it.

"Alright, you two can have your own personal blood-sucking fest, I have more important things to do." Meg stood up, and the second she was vertical, she disappeared, leaving Sam and Ruby alone.

"Ready?" Ruby asked, walking over to Sam before straddling his lap, knife already in hand. Sam's mouth watered as he stared at the demon's exposed skin, he could already taste the bittersweet blood in his mouth, and he nodded his head.

Smiling, Ruby brought the blade to her arm and let it slice into her skin, wincing only slightly as blood flowed down her white, perfect skin. Then she offered it to Sam, and he took to it like he'd never had anything to drink before in his life, and he sucked hard; pulling the blood out of the demon's vessel as hard as he could.

The small motel room soon filled with moans of pleasure from both Sam and Ruby; the human's louder than the demon's as he closed his eyes, savoring the taste of Ruby's blood. After ten minutes, Sam was full and he pulled away, catching a stray drop of blood with his tongue as it ran down the demon's arm, moaning against the warm flesh.

"Better." He whispered, pulling away and looking at Ruby, feeling the warmth of her blood settle into his stomach and veins. The demon smiled at him, and ran her finger along his bottom lip and chin, capturing blood that was dribbling down his skin. Sam breathed in and felt her finger against his lips, before taking in his mouth, sucking greedily and moaning louder than before.

"Okay, champ," Ruby whispered, pulling away from Sam and standing on the floor in front of him. "You need sleep, you're going up against Azazel tomorrow, so you need to be sharp." She smiled at him, and Sam smiled back; he liked Ruby more than the other demons, because she was nice to him, and she didn't boss him around.

Nodding, Sam stood just as Ruby vanished and walked to his bed, stripping his clothes off and laying them on the dresser beside his door, where his jacket was. Once he was just in boxers, Sam slipped between the sheets of the ratty motel bed, and settled his head against the pillow, sighing happily.

He was almost ready for his Master, almost ready to have him possess him, and almost ready to take on the angels. Sam closed his eyes and laid his hands on top of the sheet, on his chest, fingers laced together.

I can see inside you, the sickness is rising,
Don't try to deny what you feel.
(Will you give in to me?)
It seems that all that was good has died,
And is decaying in me.
(Will you give in to me?)

Sam awoke to a burning sensation against his skin, traveling further and further up his arm until it was on his neck. He writhed under the fire, whimpering until his eyes snapped open, and he saw Lucifer on top of him, smiling down at Sam.

"Morning, Sammy." Lucifer's voice was soft, almost caring, as he ran his fingernails along Sam's skin, causing him to hiss and squirm more. "I spoke with Ruby, and she said you wanted more… potent blood, is that true?" Sam's skin felt like it was on fire and he shut his eyes, aware of how disrespectful it was, and arched his back against the sensation.

"Yes, Master," Sam whimpered, feeling the fire spread to his jaw, then his lips, and he breathed heavily against Lucifer's fingertips.

"I was thinking, maybe you should drink some of mine," Lucifer cooed softly as he dipped his head, brushing his scarred lips against Sam's jaw. "If you'd want that, of course." Sam could only nod his head, whimpering as the fire found it's way to his throat. It was a good burn, of course, and Sam was drinking it all in, reveling in the attention his Master was giving him.

"Please," he whispered helplessly, feeling his cock grow hard in anticipation; the thought of drinking his Master's blood was one of Sam's fantasies and now it was coming true.

Lucifer chuckled and pulled away from Sam, causing him to whimper low in his throat and look straight up at his eyes. Then he looked down, making out the blade of a knife in the moonlight, and the glow of Lucifer's skin as he pulled his shirt sleeve up.

"Sit up, Sammy." Sam nodded and obeyed his Master's command, sitting straight up and resting his hands on Lucifer's hips, without permission. But when Master didn't push them away, or even begin to punish Sam, he kept his hands there, squeezing the narrow hips softly.

Sam's eyes locked on the blade as it laid against his Master's skin, before it dug in, and he could see blood glowing in the moonlight. Then the blade was pulled away, and Sam could smell the blood, the scent of iron and salt filling his nostrils as he leaned in, pressing his mouth against Lucifer's skin. When Sam's mouth came in contact with his skin, Lucifer shuddered and let his head fall back, dropping the knife on the bed beside them.

Then his fingers were tangled in Sam's long, brown locks, and he tugged gently, moaning loudly as Sam's tongue ran along the wound, drawing blood from it even faster. Lucifer could hear Sam's moans of pleasure, and he bit his bottom lip, sucking it into his mouth as he smoothed Sam's hair down, whispering things like, "That's a good boy, Sam," and "That's it, just like that, boy."

Every word that came from his Master's mouth only made Sam suck harder, pulling the hot blood into his mouth and swallowing it down, moaning as it scalded his throat. He moaned as the boiling liquid slid down his throat and pulled away, licking his lips and looking up at his Master.

"Master," Sam whispered, his voice rough as he leaned in, un-told, and pressed his lips against Lucifer's neck. Then he heard his Master growl, and he pulled back, fearful that he had upset Lucifer.

Sam was about to apologize when he felt Lucifer's lips crash against his own; his hand tangled in Sam's hair once more, tugging even rougher. Both of them let out moans as Lucifer pushed Sam back, and pressed his hips down against his, grinding against him. Moaning louder, Sam lifted his hands to his Master's hips again, this time pushing his shirt up, feeling his skin burn as it came in contact with Lucifer's.

"Sam," His Master whispered against Sam's lips and the sound of his name coming from those lips, especially while he had Lucifer on top of him, sent Sam into overdrive. His hands were desperately pushing the fabric up Lucifer's body, pulling at it until the demon pulled away and allowed Sam to lift the t-shirt up. Sam tossed it to the floor and took a second to look at Master's body, biting his lip as he moved his hands along the abs of Lucifer's vessel.

"This is all yours Sam," Lucifer whispered, dropping his head to graze his lips against Sam's ear, breathing hot against it. "All yours, no one else's. That's why you're my vessel, Sam; so I can be yours, and you can be mine. Don't you want that?" Sam whimpered and rested his hands on Master's hips, breathing heavy against his neck. "Don't deny what you are, Sammy," Lucifer kept whispering in Sam's ear, low and soft as he moved his hips against Sam's, feeling how hard the young man was growing.

"Don't deny me," Master growled in his ear before snapping his fingers, getting rid of the sheets that separated their bodies, along with the clothes. "I want you, Sam." Lucifer kept whispering small phrases in Sam's ear that were driving him insane, and he whimpered louder, pushing his hips up and groaning as his cock slid against his Master's.

"Oh, Master," Sam whispered, fingers splaying against Lucifer's hips and stomach, "Please, oh.. Please make me yours - do what you want.." And with that, Sam heard Lucifer chuckle before he found himself on his hands and knees in front of him; a warm hand running along his spine.

"You want this?" Lucifer asked, leaning over Sam's body, putting all of his vessel's weight on that of his new vessel. He felt Sam give underneath him and he soothed him, holding him up as he ran his fingernails along Sam's back, inching them closer to his ass.

"Yes, oh-" Sam whimpered out and hissed, feeling Lucifer's sharp nails digging into his skin as he shut his eyes, breathing in deeply. Lucifer chuckled and moved his fingers lower, spreading Sam's ass and pressing a dry finger against his tight entrance. Moaning against the tightness, Lucifer barely pushed his finger in and felt Sam's body tense, and heard him yelp softly.

"I apologize," he whispered, running a hand over Sam's back to soothe him yet again, before he pulled his finger out and spit on them, getting them nice and wet. Once they were lubed up, Lucifer pressed two fingers against Sam's hole, and pressed in again, this time slower than before.

He listened carefully to Sam's breathing, and when it became even, he pushed his fingers in further, spreading them slightly to get Sam ready for his cock. Soon, Sam's panting turned into moans, and he was pushing back against Lucifer's fingers, urging him to go deeper. Laughing, Lucifer pulled his fingers out and spit on the palm of his hand, before rubbing the saliva on his cock, getting it lubed up.

"Okay, Sam," Lucifer sighed as he lined up with Sam's ass, pressing the head of his cock against him, feeling his muscles relax, then constrict around him. Closing his eyes, Lucifer pushed further into Sam, until his hips were touching the cheeks of Sam's ass, and he moaned loudly at the feel of Sam's tightness around him.

"Master!" Sam all but screamed out as he dug his nails into the bed, and pressed his face against a pillow. His insides felt like they were on fire, but he was slowly adjusting to his Master's length and girth, and even began pushing himself back against his Master.

"That's it, Sam.. ugh.." Lucifer bent over Sam, his hands gripping both of his ass cheeks, as he began pushing deeper inside of the man's body. Sam whined loudly, arching his back before pressing himself against the mattress, sticking his ass high in the air.

"Oh, god.. That's a good boy, Sam.." Lucifer was moaning as he pulled out of Sam, and slammed back in, swallowing hard as he heard skin slapping against skin. The noises around him - Sam's moans, the sound of his skin as it came in contact with Sam's - mixed with the feeling of Sam's muscles tightening around his cock almost sent the demon over the edge.

"Do you want me to cum in you?" Lucifer purred in Sam's ear as he licked up the curve and bit it gently, pressing harder into Sam's body. He felt the man nod against him and he smiled, dropping his mouth to his neck and biting gently.

"Stroke your cock for me, boy," Lucifer demanded as he bit Sam's neck harder and fucked him even rougher - feeling Sam's body shudder against him. The room suddenly filled with the smell of sex, blood, and sweat, and that made Sam wrap his hand around his cock tightly, and tug it fast, breathing heavily.

"That's it, fucking stroke your cock." Lucifer was growling at this point as he fucked Sam harder, his cock throbbing deep inside Sam's ass, as his balls tightened. He knew he was going to cum soon, and he rammed his cock into Sam harder, causing the young man to scream out, and he smiled in triumph.

"Cum for me, Master," Sam whimpered and that did it; Lucifer slammed into Sam one last time, cumming deep inside of him as he gasped loudly, falling against Sam's sweat-slick back. Sam groaned and gave his dick a couple more tugs, before he was cumming all over his hand, and the bed underneath him.

Breathing heavy, both Lucifer and Sam laid there in the same positions until Lucifer got his breath back and he pulled out of Sam with a loud grunt. Sam fell to the bed, in his own mess, too exhausted to care about it as he tried catching his breath.

"Think you're ready for me now?" Lucifer whispered, placing kisses all along Sam's back, smiling against his damp skin. Sam nodded and mumbled incoherent words against the pillow, but Lucifer caught all of them; Sam had said he was ready to be Lucifer's vessel, and he would do his best to serve him.

"I know you will, Sammy boy, I know you will.." Lucifer cooed before Sam's eyes drooped, and he fell asleep; sore, sweaty, and lying in his own cum. Watching his soon-to-be vessel, Lucifer grinned and snapped his clothes back on, before leaving Sam like he was; he'd see him tomorrow, after he had Azazel inside him, and if he survived that… Well, if he survived having one of Lucifer's strongest demons inside of him, then he'd survive having the Devil himself inside him, for a second time.

Sam slept, that night, better than he had in months; he didn't toss, didn't turn, and had no nightmares about his future, or about his past. All he dreamed about was Lucifer, and being his servant, and his only. Sam was committed to his Master, one-hundred percent, and couldn't wait to be his vessel.