AN: Originally I wrote this for my drabble/ oneshot Merlin series and I just felt like this should be posted here. So... here it is!
Disclaimer: I don't know Supernatural or Merlin.
Arthur, Merlin, and the Knights burst into the throne room. They all had their swords at the ready (except Merlin, who never has any sort of protection but always survived anyways and no-one ever finds that a suspicious at all) all of them ready to strike at any moment.
Morgana sat on the throne calmly and smirking confidently. She looked proud and extremely smug.
"Morgana," Arthur addressed her almost casually.
"My dear Arthur," Morgana stood up from the throne and started slowly walking side-to-side in front of the throne, as if observing them.
Merlin stepped forward, his eyes dark and his face expressionless, "You're trapped, Morgana. There's nowhere to run."
Suddenly they were interrupted by the sound of people entering the room behind them. They all turned around to find three strangers each wearing strange clothes.
One of the strangers was really tall, about as tall as Percival, and had longish, brown hair. He wore some strange blue pants and some kind of strangely patterned tunic with a jacket. He held a small knife out as if ready to strike.
Another stranger was shorter with short, sandy blonde hair. He had the strange type of pants but wore a black tunic with a pendant hanging around his neck and a green jacket. He had a large jug of water at the ready.
The last stranger was even shorter, about Arthur's height, and had dark brown hair. He had some kind of weird uniform on and a long tan overcoat. He had a long, silver dagger at the ready.
"Sorry to crash the party, your highness," the stranger with the water said in a gravelly voice. "We got a call about a demon possession."
"Who are you?" Arthur asked evenly, holding his sword out at them.
"Ah, the Winchesters," their attention was brought back to Morgana who was still smirking but there was a bit of fear in her eyes. "I was wondering when your wonder angel was going to taxi you here. Took you long enough."
"It's been awhile, Meg," Sam replied.
The Morgana's eyes turned pure black, "Look who won the prize."
"What the Hell?" Arthur exclaimed, looking at his half-sister's black eyes.
Morgana's eyes turned back to normal and she sneered, "You really are an idiot, you stupid, pathetic little King,"
"She's possessed by a demon, Arthur Pendragon," the man with the black hair told the young King.
"Yahtzee," Morgana chuckled. "I'm surprised you didn't piece it together already. I'm especially disappointed in you, Merlin. I guess the legends aren't all they're believed to be."
"What have you done with Morgana?" Arthur growled.
The demon examined her fingernails, "Oh, she's somewhere in here. Screaming, trying to claw her way out. It's really quite pitiful, actually."
"How long?" Merlin snarled, his voice seething with anger. "How long have you been possessing her?"
"I lost track," the demon shrugged innocently. "A few years at least. And she's seen terrible things. Things that would drive you mad."
The King yelled out in rage and had to be physically restrained by a few of the knights to stop him charging at the possesed Morgana.
"Of course, she still has magic," the demon walked a down from the throne a little bit, "That, I couldn't fake even if I tried. I've just helped it along. Trained her in the ways of black magic."
The man with the small knife stepped forward, "Get out of the girl, Meg."
The demon cackled, "Ah, Sam Winchester, what are you going to do if I don't, huh? If you stab me, you'll kill her and we don't want this pretty face going to waste, now do we?"
The other man with the water ran from the side where he had been discreetly making his way toward her and threw the water on her. The water sizzled on her skin and she shrieked in pain, her eyes turning black.
"Exorcizamus te, omnis immundus spiritus," Sam recited as the demon was occupied, "omnis satanica potestas, omnis incursio infernalis adversarii, omnis legio-"
She threw out her arms and the two men went flying backward.
The third man picked up the incantation, "-omnis congregatio et secta diabolica. Ergo draco maledicte et omnis legio diabolica-"
The knights, Arthur and Merlin could only stand and watch as the third man was sent flying back with his comrades. The other two men were just recovering.
"-adjuramus te. Cessa decipere humanas creaturas-" Sam stopped when black smoke suddenly burst from the mouth of Morgana and rose through the air and left the room.
Morgana's body went limp and fell to the ground. Arthur caught her before she hit her head and held her close to his chest. All of the knights (and Merlin, of course) went forward and watched as she opened her eyes which were back to their normal green.
"Oh, Arthur!" She cried and buried her head into her brother's shoulder and she started sobbing.
Merlin backed away from the group of knights and went over to the other men who were helping their black haired friend up from the floor.
"Thank you," the warlock said reverently.
The man with the sandy blonde hair turned to him, "Don't mention it, kid. Just a normal day in the lives of the Winchesters."
"Who are you?" Merlin questioned.
"I'm Dean," Dean pointed to himself. "That's Sammy," he pointed to the other taller man.
"It's Sam," Sam corrected sternly.
"And that's Castiel," Dean pointed to the man with the black hair.
Merlin smiled, "I'm Merlin."
"Yo-You're Merlin?" Sam stuttered.
"Yeah, have you heard of me?"
Castiel jumped in, "The name is uncommon where we come from."
The warlock nodded slowly and looked behind him at his group of friends.
"We should get going," Dean said.
"Yeah, we should," Sam agreed.
"Well, thanks again-" Merlin turned back to the strangers but they had vanished.
And so Camelot's ban on magic was lifted, freeing Morgana and Merlin. Of course, when Merlin told Arthur, Arthur instantly had him thrown in the stocks for two hours but that was just payback for not telling him sooner.
Morgana was accepted in Camelot again and restored bonds with her friends. She became an important member in Arthur's council and the brother and sister grew closer.
The three strangers were never seen or heard from again, but Arthur declared that he was in debt to them forever and if they were to return a huge feast would be thrown in their honor.
The end.
AN: Sorry if the ending is a bit awkward, I was having a bit of trouble ending it correctly. Please leave a review and also check out my drabble/ oneshot Merlin series called Change you'll find it in the Merlin category. Thanks :)