Disclaimer: I own nothing.

Warnings – dark, mature content, featuring Dark!Arthur by the end. Please don't read if that offends.

Merlin slowly opened his eyes, relishing in the warmth and comfort he had been sleeping in, and for a long moment, wondered what had awakened him. Then he felt teasing fingers running lightly up and down his thigh, another body pressed flushed against his. He smiled in contentment, leaning back into his lover and letting his head rest in the spot at the base of Arthur's throat.

"Morning," he mumbled sleepily, closing his eyes again even as he snuggled back. Only to feel something pressing into his hip, a clear sign that Arthur too was appreciating Merlin pressing in closer.

"Already? It's too early." The servant moaned half-heartedly, his words betrayed by the fact his body was beginning to respond to Arthur's touch. His master just laughed softly in his ear, one arm sneaking around Merlin's shoulders and across his chest as he held him even closer.

"It's your fault, Merlin," he drawled, the warlock felt shivers running down his spine at the voice. There was nothing more satisfying than waking up in the arms of Arthur Pendragon. "So why don't you do something about it?"

Merlin smirked. "I could," he muttered, "or I could just get on with my duties like I'm supposed to be doing." He made to get out of the bed, a teasing smile playing across his lips. He never intended to get very far, and sure enough, Arthur's arm tightened and Merlin found himself slammed back down onto the bed.

"Don't you dare! You have other ways of carrying out your duties; the door is locked, after all." There was certainly something smug in Arthur's voice, and Merlin felt his grin widen as he mumbled something under his breath and his eyes flashed golden. Immediately, Arthur's chambers began to tidy themselves and the prince hummed appreciatively, growing harder against Merlin's hip as he watched the magic. Knowing that if they were to get anything done, or for that matter, even make it out of the bed, Merlin let his hand drift behind him.

For a moment, he just let his fingers brush along Arthur's torso, tracing the well defined muscles that he knew so well. Arthur's own hand tightened slightly on his leg as he arched into the touch, a noise slipping past his lips that, as Crown Prince, he would never admit to making.

"Merlin." There was a warning growl in Arthur's voice now, and whilst he knew it made most of the servants run in fear, Merlin just smirked again, letting his fingers brush with feather lightness down Arthur's side, the royal jerking slightly as he brushed over a ticklish spot. It was so easy to make the most feared warrior of Camelot come apart. All you had to do was know the right spots.

"Yes, Sire?" Merlin asked innocently, his hand still wondering, but completely by-passing where Arthur wanted him to go, instead moving onto the man's legs.

"Damnit Merlin, just do it."

"Do what, Sire?" Merlin knew full well what his tone would be doing to Arthur, and sure enough, the man snapped. His hand left Merlin's thigh, and with one movement, he flipped the warlock onto his stomach, straddling his lover in the same movement.

"You know full well what." His smile turning into a full blown grin, Merlin flashed his eyes before nodding at his master. Arthur's own hand was now drifting down Merlin's back before sliding in between his cheeks.

"Fuck," Merlin moaned, his body arching backwards as Arthur's fingers continued to play.

"Problem, Merlin?" Now it was Arthur's turn to sound innocent as he finally unwrapped his arm from around Merlin's chest. He pushed his hand between Merlin's body and the covers of the bed, and was rewarded to find Merlin's now rock-hard cock waiting for him. Strong fingers wrapped around the man's throbbing erection, and Merlin moaned again.

"Damnit Arthur, I've done the spell, just do it!" Merlin may have believed he was the one with the power to make Arthur come undone, but the prince knew full well he could have the most powerful warlock the world had ever seen begging with just a few strokes. Gripping Merlin's cock firmer, he dragged his hand across it, and was rewarded with another noise that went straight to his own erection.

"Fuck it," he muttered, lining himself up. Merlin's spell would mean all preparation had been done, and sure enough, Arthur's cock was slick with oil. It saved so much time, especially first thing in the morning. His free hand braced himself against the headboard as he sheathed himself fully in his lover, Merlin immediately gasping as sensations shot through him and danced across his skin. For a moment, Arthur didn't move, before Merlin suddenly bucked upwards.

"Move!" He all but yelled, but his master smirked. He let go of the headboard, placing his hand on the back of Merlin's neck and holding him still.

"Anyone ever tell you patience is a virtue?" He murmured softly, placing light kisses across the back of Merlin's neck and down his back.

"There is nothing virtuous about you, Sire, so fucking move!" Arthur contemplated staying still just to annoy his lover, but found that his own needs were beginning to grow by the second. Agonisingly slowly, he drew back, almost until he was completely out of Merlin, before slamming himself back in, hard. The hand on Merlin's cock followed the same rhythm as his thrusts, and it didn't take long until Merlin reached his climax, coming all over Arthur's hand and the bed.

The prince continued to pump Merlin through his orgasm, and the second his lover had finished, released his own seed into the pale body beneath before promptly collapsing onto Merlin, still balls deep in the man.

For a long moment, the two of them of them simply lay there, panting, before Arthur slowly drew out, causing another moan from his lover. Brushing his lips against the back of Merlin's neck as he held him closer, Arthur inhaled deeply.

"Get me my breakfast." He muttered, and Merlin turned in his grip, turning to face the prince. His thumb brushed across Arthur's lips as he pressed a kiss against the blond's temple.

"Only if you get yourself dressed." And just like that, the servant was gone. Arthur smiled sleepily as he lay back in his bed, watching Merlin dress before slipping out of the door. He would be back, and would find the prince halfway through getting dressed, as always. And, just like always, would find himself stepping into help, and clothes would end up getting confused as to whether they were coming on or off. Snuggling into the covers a little more, Arthur smiled; his heart swelling with the happiness that had infected his life. His father still managed to undermine at every opportunity, sorcerers still attacked him about three times a day and his new Knights simply didn't seem to be able to hold onto their swords. But Merlin was always there to make it better, and Arthur could ask for no more.

Things didn't stay that way though. Merlin wasn't sure when the changes began to take place. There was always something rough in their actions whenever they fucked, but the warlock was feeling something else. There was something almost desperate about Arthur's movements as he pounded himself into his servant. There wasn't the same loving murmurings afterwards either, more like an order as the prince rolled away. Merlin knew it was whenever Arthur had a meeting with the King that the actions came about, as if he needed to find a way to assert himself. Merlin had given himself to the prince long ago, and so he dealt with it like always, calming him afterwards and just allowing Arthur to vent out his frustrations. Whilst the pain was more than their love making had provided before, it wasn't as if Merlin wasn't getting pleasure out of himself, despite at times barely being able to walk after Arthur had fucked him in three different places around the room, one after the other before finally collapsing into an exhausted heap on the bed.

But when Arthur burst through his chamber's doors before locking them behind him, Merlin knew something was wrong. He threw the pillow he had been attempting to plump back on the bed and was across the room like a shot. One hand cupped Arthur's face, the other resting on his hip as he drew the man in.

"What is it? What's wrong?"

"Like it is any of your business." Arthur snapped, pushing away his lover and stalking across the room, throwing his sword down on the table with a clatter before turning back to face Merlin. Immediately, he winced at the hurt look that had shot across the warlock's face.

"I would have thought," Merlin began in a slightly chocked voice, "that after everything we have been through, everything we are, you would not try and shut me out." The servant turned his back on the prince, automatically beginning to tidy something in order to have something to do with his hands to stop them from trembling. Arthur had never spoken to him like that, even when he had been no more than the man's servant rather than his lover. But this was not the first time Arthur was beginning to take his bad temper out on Merlin, and quite frankly, the servant was getting annoyed with it.

"I'm sorry," Arthur was suddenly next to him again, taking the goblet out of Merlin's hands and turning him around, kissing him gently. "It's just...he..."

"Don't let him get to you, Arthur." Merlin whispered gently, his hand once again reaching out to cup Arthur's face. As his thumb brushed across Arthur's cheek, the anger left the prince and he closed his eyes, sighing deeply. Merlin smiled, continuing his actions even as he leaned forward and kissed Arthur on the end of the nose, gaining himself a smile from his prince. "You're a much better man than he is, you'll make a much better King."

Merlin didn't even have time to gasp before he was slammed against the wall, Arthur's breath hot on his face even as the royal pinned his wrists above his head.

"That's treason, Merlin," Arthur almost snarled, looking deep into the man's eyes for a long moment. Merlin swallowed hard at seeing the anger burning deep within. This was not his Arthur.

"Stop it..." He muttered, trying to pull against Arthur's grip. It only fuelled the prince's anger and Merlin winced as he was brought forward before being slammed back again. With a sinking heart, he took in the anger in Arthur's eyes and the arousal in his groin. Before he knew what was happening, Arthur was kissing him fiercely. None of his usual tenderness was present as he forced his tongue into Merlin's mouth, claiming him for his own. He shifted his grip so it was only one hand pinning the warlock's wrists whilst his other hand began to wander. Whilst his own body was beginning to react to the attention it was getting, Merlin knew they couldn't continue like this.

He forcibly pulled his head away, cringing at the coppery tang of blood on his lips.

"No, Arthur, I don't want this."

"I don't care. You are the servant, Merlin, serve me." Merlin gaped in absolute shock. He knew now Uther must have said something about Arthur's control over the people, it was the only explanation for the prince's violent behaviour. As Arthur's teeth bit down on his shoulder blade, Merlin brought up his knee; following it with a quick flash of his eyes that had Arthur sprawled across the floor. Rubbing his sore wrists, he glanced down at Arthur, a mixture of sadness and disappointment in his eyes.

"You swore you would never force me into something I didn't want." He said quietly, tears stinging his eyes. Arthur's face seemed to close down for a moment before a look of horror and desperation shot across it.

"Merlin...I...I'm sorry..." Merlin sighed heavily as he looked down on the defeated positioning of the prince. Arthur truly did look mortified at what he had done, and deciding to trust his love once more, Merlin knelt down next to him, wrapping his arms around the golden-haired prince.

"Come back to me, Arthur," he whispered in the man's ear, and very slowly, he felt Arthur sag against him, suppressed emotion making him shake. "It's okay; everything is going to be okay, I'm right here. I always will be."

"Merlin?" Arthur's voice sounded almost pleading. "Stop me. Don't let me become him."

"Never," Merlin promised, planting a kiss on top of the blond locks, holding Arthur close. No one else saw Arthur at his most vulnerable, and Merlin was determined that no one else ever would. Arthur was his to look after, and what kind of lover would he be if he failed at that? Nudging the man to his feet, the warlock guided him over to the bed. Sitting Arthur down on the edge, he pulled the prince's boots off before laying him back. Arthur's hand drifted down Merlin's stomach and onto his crotch, but Merlin gently and firmly pushed him away.

"Sleep." He ordered softly, pulling the covers around the man. He had to make Arthur believe he truly would look out for the prince, and hitching himself onto the bed, Merlin let his hand run through Arthur's hair as the man succumbed to sleep under his touch. With magic at his disposal, Merlin knew he would be able to keep Arthur under control. If he could stop the man giving into his anger, he would be able to stop the son following the path of the father.

Unfortunately, Arthur didn't see things the same way. Uther passed away in surprising ease, just slipping away in his sleep rather than the horrendous end Merlin always imagined would claim the King. Arthur's coronation went without hitch, unless you count the man all but sobbing into his lover during his last night as a prince. Merlin had been there though, and it was with his head held high that Arthur accepted the crown with the dignity he had always managed to possess when in the public eye.

But then problems had begun as the royal discovered just how hard running a kingdom truly was. His pride refused to allow him to delegate some of the minor jobs, and Merlin found he was being forced to use his magic more and more to stop Arthur's advances, knowing he would regret it when he came to his senses. For the first time in years, being the blond's lover had become a chore rather than a pleasure.

Merlin knew immediately that Arthur wasn't still in bed when he awoke on a dull morning. There was no familiar weight dipped next to him, nor the comforting whisper of the King's breath on the back of his neck. Merlin rolled over and opened his eyes blearily, sighing in relief when he caught sight of Arthur standing at the edge of the bed, watching him with a strange smile on his face.

"Hey," Merlin murmured softly, smiling up at him sleepily. He was just glad to see Arthur was looking more like himself than the cold man who had appeared after the coronation. He frowned as he shifted slightly, something felt wrong. As he glanced at Arthur quizzically, he saw the man's smirk widen, and suddenly felt a stab of panic.

He sat up quickly, and the room lurched alarmingly. Arthur's arm was immediately supporting his back, helping him sit back on the pillows again. Merlin let him, frowning in confusion when the royal's hand drifted down his arm before circling something cold on his wrist. Opening his eyes, Merlin frowned to see a strange cuff glittering around his wrist. Runes were etched into it, deep and mystical, and one glance showed there was an identical one on his opposite wrist.

"Light the fire, Merlin?" Arthur asked quietly, keeping a hand on his shoulder in order to stress the point he wanted Merlin to use magic to do it. Rolling his eyes, Merlin concentrated and let a word roll of his tongue. Nothing happened apart from another bought of light-headedness, followed by Arthur's laugh.

"They work? Gods, they actually work!" There was such childish excitement in his voice that Merlin didn't feel worried.

"What are they?"

"I found them in the vaults. Geoffrey said they bind a person's magic, and before the Purge, it was what was used if a criminal had the potential to escape."

"And they are on me because..?"

"I wanted to see if it was true." Arthur responded honestly, and Merlin pushed himself into a more upright position. He didn't like this, not considering the mood Arthur had been in lately.

"Get them off now you know?" He asked, shaking his head to try and clear his vision. When he glanced back at the King, Arthur's face had clouded over.

"You seem to like giving your orders these days, Merlin. How many times have you used magic against me lately?"

"Arthur, what are you doing? Just give me the key."

"No." To Merlin's horror, Arthur stepped back from the bed, leering in a way that was so unlike Arthur, Merlin wondered for a moment whether the man had been possessed and Merlin had just not noticed. But then he looked into Arthur's eyes, and knew it was the man he had loved all these years looking back at him. But unlike the naive prince, this King was one hardened by war and betrayal. All the things Merlin thought he had helped the man get over were brimming, just under the surface.

"Arthur, let me go!" Merlin scrambled out of the bed, his foot catching around the covers and sending him sprawling at Arthur's feet.

"Now that is where you really belong, Merlin."

"Stop this! This isn't you!" Merlin wasn't expecting to be pulled into a kneeling position, shoved back against the bed.

"You want the "me" you know then, Merlin?" Arthur growled. Before Merlin knew what was happening, the King had freed his throbbing erection from his breeches, his hand forcing Merlin's mouth open. "This is the "me" you are most acquainted with, is it not?"

Instinctively, Merlin tried to use magic to make Arthur back away, but only was rewarded by another bought of light-headedness and Arthur's suddenly cruel laugh ringing in his ears as the King forced his cock into the back of Merlin's throat. His hands braced against Arthur's knees as the royal began a punishing rhythm of thrusting into the warlock's throat, making him gag.

Arthur didn't even notice the warlock's struggles as he brutally fucked his once-lover's mouth without a care to the fact that he was destroying the man slowly and painfully. When he finally came, he glanced down into a tear streaked face. He rolled his eyes as he pulled away, retying his laces and striding away. He had just reached the door when a whisper made him stop.

"What happened to you?" There was a heavy silence for a moment.

"You swore you wouldn't let me become my father. So why have I just had to sentence three people to death? You betrayed me, Merlin."

"No, Arthur, I..." Merlin's shouts were cut off as Arthur strode from the chambers, locking the door behind him and leaving a broken warlock trembling on the floor. All he had to do was making Arthur see sense once again...

Arthur never did see sense. Someone had fed him the idea that Merlin had betrayed him, and the belief the man he had given everything to had turned around and stabbed him in the back caused the once passionate man to crack, burying his heart away.

He never was going to let Merlin forget it. The cuffs stayed on, Merlin getter weaker and weaker by the day as his magic was drained from him, confined to the King's chambers. Whenever Arthur returned, he would flinch back. He could do nothing to stop the crazed man from slamming him over the table or forcing him to his knees. With no spell available to ease the pain, he was forced to feel every thrust, every punishing grip as he was forced against the wall, breeches tangled around his knees and Arthur's thick cock sawing into his arse.

After a time, he stopped fighting. He had once said to Gaius without his magic, he may as well die. He believed that more than ever now. He was kneeling on Arthur's bed, naked and bound. The cuffs had never been removed since the day Arthur had put them on, and were currently attached to chains hanging from the top of the bed, keeping his hands above his head and his body in an upright position as he waited for the King to return.

A click as the door was unlocked made Merlin close his eyes, a few hot tears slipping down his cheeks.

"Traitor." Merlin swallowed thickly.

"I never betrayed you. All I did was love you, Arthur. I thought you loved me in return."

"I'll show you how much I love you." Arthur's primitive growl made Merlin shake as he heard the sound of the King's sword being thrown on the table and the bed dip under the man's weight.

One hoarse scream was the only sound he made as Arthur pushed himself in without warning, the warlock slumping in his chains.

He had stopped Arthur from becoming his father as the man had begged, no one could deny that.

Instead, he had created something far worse.