A/N: I've had this hanging around for a little so I thought I'd post it up. Firstly, I want to say I have not been entirely faithful to the original story of Sir Gawain and the Green Knight - but I reason that's fine, since TPTB haven't exactly been faithful to the entire Arthurian Legend (that is not any form of criticism, btw); secondly, those that are familiar with the legends will notice that I have incorporated a tiny bit from other legends - it's artistic license and I know they are not from the original.

So, please enjoy!

Disclaimer: I own nothing.

It was a normal day in Camelot. The sun was out, a mild breeze blew through the city and people went about their business happily or at least without much reluctance. The knights were out training, or horsing around depending on how you looked at it, and the air was filled with metal clashing on metal and the sound of grown men being slammed into the earth by their peers.

On the edge of the training ground, Merlin sat watching the proceedings with a smirk, while idly polishing Arthur's chain-mail. The only way knights could think this was fun was if they were already short a few vital brain cells. That was why losing the rest did them no damage. He winced as Arthur hefted Elyan over his shoulder and flung him to the ground with a dull 'thud'. Elyan floundered like a fish for a moment and Arthur, with a characteristic lack of mercy, dropped an elbow into his brother-in-law's stomach. It was enough for the knight, who raised his hand submissively and gasped, "You win! You win!"

Chuckling, the king reached down and pulled Elyan to his feet, giving him a friendly punch to the shoulder. "Your technique's getting better," he consoled.

"Thank you," Elyan replied, rubbing his stomach. "I think."

Merlin shook his head. Crazy. The lot of them. To his left Gwaine was struggling to even move Percival, who stood, his feet planted well apart, with a grin on his face and his arms crossed. After a few moments of futile shoving, the large knight stuck one leg out, hooked it behind his opponent's and with a careless shove to Gwaine's opposite shoulder sent him sprawling. Everyone watching had a good laugh at Gwaine's expense, which the the unfortunate knight took with a good grace by kicking the back of Percival's knee with one foot at the same time as scissoring his other foot into the front of his legs. Percival landed with the impact of a small tree and Gwaine jumped up with a smug grin on his face.

"You cheated!" Percival said with mock outrage.

"No. I took advantage of your overconfidence, my friend."

"You'd never beat me in a fair fight."

"I've said it before and I'll say it again, that's not much incentive for me to fight fair is it?"

"That's not the point, Gwaine," Arthur interjected. "It's all about technique. No matter who your opponent is, the warrior with the best technique will always win."

Merlin sniggered at this and muttered, "Why don't you give it a try then?"

Unfortunately for him, Arthur actually had quite good hearing when it suited him and he overheard his servant's quiet insolence. "Is there something you would like to add, Merlin?" he asked with false interest.

Merlin stopped polishing with a nervous look on his face and held his hands up submissively. That tone never heralded anything good. In fact, more often than not, it ended with him getting pummelled by someone with a sharp sword. "Nope," he replied innocently. "Nothing at all, Sire."

"Really?" Arthur asked with unnerving friendliness, as he wandered up to his servant nonchalantly. "Because it sounded to me like you were offering to show us all how it should be done."

"What?" Merlin exclaimed in horror. "No!"

Arthur gave him a final feral grin and with lightening speed hooked one arm around his servant's neck, effectively cutting off his air supply and started knuckling the younger man's head with his other hand, heedless of his cries of protest. A few seconds later and Merlin found himself flying through the air and landing on the not-so-soft grass. The impact had not been as bone-crunching as he'd been expecting though and he had a sneaking suspicion that Arthur had taken the venom out of the throw at the last moment. Still it felt like someone had dropped a tree on him. He closed his eyes wishing the world would stop spinning.

"Oh stop being so melodramatic," Arthur grumbled, patting his servant's cheek none too gently. "Get up."

"So this these are the legendary Knights of Camelot?" scoffed a deep voice behind the group. "Bullies who can only beat up pathetic servants. No wonder the honour of these men is spoken of the length and breadth of the land."

The entire group turned to see who this arrogant visitor was and Merlin took the opportunity to push himself off the ground. The newcomer was clearly a knight, his armour covered in a dark green surcoat, his face covered with a helmet and sat on a large white horse, also covered in dark green trappings. There was an aura of power about the man that even the normally oblivious knights picked up on, but it was the raw magic the flowed through him that made Merlin stumble backwards. Never had he encountered such powerful magic in one being, not even the Great Dragon emanated such unfettered magic.

"And who are you, sir, who comes to another man's kingdom and judges so quickly?" Arthur asked acidly, pushing his way to the front.

"Who I am is irrelevant," the stranger stated coolly. "I have come to prove that the honour of the Knights is worthless." Removing his gauntlet, the knight urged his horse forward and flung it at the feet of Sir Edric in obvious challenge. Edric, a young but skilled swordsman, could do nothing but put up the gauntlet and ask what the terms of the duel were to be.

"It is a simple test of honour," stated the knight, his voice a deep monotone. "The challenge is to the death. You may strike me with one blow, I shall not resist nor defend against it. I shall deal the same blow to you but you must not lift a finger in your defence."

"Very well," Edric stated, drawing his sword.

The strange knight swung himself out the saddle, towering above the assembled men, half as tall again over Percival and pulled a massive axe from a loop on the saddle. Suddenly, Gwaine pushed his way to Edric's side and held out a hand in protest.

"No!" he cried. "Edric, it's a trick."

"The challenge has been accepted," the knight said tonelessly, swinging the axe blade into the ground. Percival pulled Gwaine away, although the dark-haired knight struggled and continued to protest.

The strange knight spread his arms wide. "You may begin."

Edric settled into a solid stance, drew his sword back and with a quick well aimed thrust, drove the weapon into the knight's chest, piercing cloth, mail and skin deep into the heart of his opponent. Almost as quickly, Edric withdrew the blade and watched with expectation clear on his face. The green-glad knight took a stumbling step backwards but even as Edric sheathed his sword, the stranger took a deep breath and stood up tall, drawing his own sword from his belt.

"A fine stroke," he said without malice. Edric's expression changed from confusion to horror as he realised the killing strike had not felled his opponent as he had thought and now he would have to stand the same blow. Only he would not simply shrug off the wound as the other man had. Oblivious to the cries of protest and horror from his comrades, Edric could not take his eyes off the great sword that would end his life.

Without hesitation or pity, the helmeted knight plunged his sword into the hapless young knight's chest in an identical stroke to the one he had inflicted. Edric opened his mouth in a wordless scream before his eyes rolled back in his head, the knight removed the deadly weapon and Edric collapsed lifeless to the ground. Elyan and Percival rushed to the dead man's side, Arthur looked like he was about to do something foolish and Gwaine stood rooted to the spot, the normally cheerful and laid-back knight reduced to complete silence.

Merlin dragged his gaze from the magical knight when he saw Arthur begin to unbuckle his arm guard with clear intent. The king's sense of duty and honour would force him to challenge the supernatural warrior despite his inability to win. Without pausing for thought, the servant rushed to his master's side and with surprising strength wrapped his arms around him, preventing him from throwing his arm guard at the knight's feet.

"Don't be stupid," he growled in Arthur's ear. "He'll kill you."

"Let go of me!" Arthur shouted, struggling.

Heedless of the devastation and fury around him, the green knight pulled his axe from the ground and swung himself into his saddle. He urged his mount towards Gwaine. "You have one week to keep your promise to me, Sir Knight. Or this shall be the fate of all your fellows." With that he kicked his heels back and galloped away to the forest.

A/N: Thoughts? Opinions? Please let me know!