Word Count: 15,808
Characters/Pairings: Gen, past Arthur/Gwen
Warnings: Violence towards children, character death
Spoilers: Spoilers through series five of Merlin, AU season four of Supernatural
Summary: Centuries after his death, destiny calls Arthur Pendragon forth to fulfill his duty as the Once and Future King. But Arthur is also a Winchester now. Destiny won’t know what hit it.
Author’s Notes: I want to thank chosenfire28 for running this challenge. And to finnickodair, your artwork is awesome, and gorgeous. Thank you so much for picking my story. :)
A week after Merlin’s arrival found Arthur hiding in his tree house, sword at his side, and a pillow over his head. The headache he’d woken up with this morning had been mild, nothing more than his allergies acting up due to the changing weather.
Once breakfast had been eaten, his Uncle Sam and Merlin had gone back to researching, piling stacks of old dusty books over every flat surface they could find. Arthur had some work he’d had to do for his dad so he’d spent the morning outside, buried in the hood of a car. When he’d come inside for lunch, his dad and best friend where in the middle of reenacting the Cold War.
He didn’t know how to make things better. He loved his dad, and Merlin was his other half, the person he’d trusted the most. And if they sniped at each other one more time, Arthur was going to bribe his Uncle Cas into locking them into the panic room, without weapons, or magic. His Uncle Cas was an angel, he was pretty sure he could pull it off.
A timid knock had Arthur scurrying to pull the blanket up over himself. He lay still, hardly breathing; hoping whoever was invading his privacy would be fooled into leaving.
The nudge where his foot rested dispelled that fantasy, but he refused to budge.
“Go away.” Arthur pulled the blanket tighter around himself.
“Tough,” his Uncle Sam said. The blanket was soon yanked off him, and he gave his uncle the deadliest glare he could manage. Sam only laughed harder at him. “If I have to suffer with them then so do you.”
Arthur shook his head and buried it under his pillow again. “Not if I go back to Avalon. I’m pretty sure I could talk Uncle Cas into taking me there.”
“Come on,” Sam said, stealing his pillow too. “Give them a break. Everyone is just worried.”
“Worried?” Arthur said with a disgusted snort. He sat up and ran his hand through his hair. “Dad is ready to unleash his own version of the Great Purge, and the last time I saw Merlin that twitchy was right before Camlann.”
“The Great Purge?” Sam asked as he settled on the futon next to Arthur.
“When I was born,” Arthur said, voice soft. He kept his eyes downcast and picked at the seam of his jeans “The first time, my mother died and my father blamed magic. He committed genocide.”
“I see,” Sam said. “Sounds like your grandfather, minus the innocents getting slaughtered.”
Arthur sighed and, buried his face in his hands. “Why can’t they just pretend to get along?”
Sam snorted and patted Arthur’s shoulder.
“This is your dad and your best friend we’re talking about here. They both want the same thing, they’ve just got different ideas on how to achieve it.”
“Merlin believes in destiny,” Arthur said. “Every time he tried to defy it, the prophecies ended up coming true.”
“And your dad and I turned destiny on its head,” Sam said.
“How’d you do it?” Arthur asked.
“It wasn’t easy,” Sam said. “We lost a lot a good people.”
“But you did it,” Arthur said.
“For us, to give in would have caused more harm than defying it,” Sam said. “And we didn’t give up on each other.”
Arthur sighed. “I wish Gwen was here. She’d make sure they behaved.”
“Yeah,” Arthur said. “She always knew what to say.”
“Arthur.” Merlin’s shout had them both looking up. His head followed through the trap door. “We’ve found something.”
Arthur jumped up, and headed out of the tree house. He met Merlin at the bottom and they both took off, not waiting for Sam to meet them. Soon they were in the kitchen, his dad standing off by the sink, something alcoholic filling his glass. Arthur felt his stomach fall to his feet. He’d never seen his dad looking so lost before. Coming up to his side, Arthur nudged him, his eyebrow raised in question.
Dean downed his drink, placing it in the sink, before turning away and heading towards the table. Arthur felt his worry increase.
“Dad?” Arthur asked just as his Uncle Sam ran in.
“Great,” Dean said, clapping his hands. “The gang’s all here.”
“What’d you guys find out?” Sam asked coming over to the table.
Merlin pushed a book forward and pointed to a passage written in faded ink.
“This describes a ritual to harness the world’s magic,” Merlin said. He cast a look at Dean, and Arthur felt his shoulders stiffen.
“What does it do?” Arthur asked. They remained silent and Arthur felt his irritation grow. “Merlin?”
“It’s possible Zachariah could use the extra power to crack Lucifer’s cage open.” Dean now had the bottle in hand and he gave a mirthless cheer. “The world’s ending again, Sammy, and the duchebags wanna use my son to do it.”
“It calls for the willing sacrifice of a child of magic,” Merlin said.
“But I wasn’t born of magic,” Arthur said. “Not this time anyway.”
Merlin shook his head. “It doesn’t matter. You’re the Once and Future King.”
“Wouldn’t it work with someone like Merlin?” Sam asked.
Dean shook his head. “We asked Cas already.”
“I’m a creature of magic,” Merlin said. “If he used me in the ritual the power would be lost.”
“So, what do we do?”
“I vote for killing Zachariah,” Dean said, taking a drink from his bottle. He slammed it down on the table, looking each of them in the eyes. “Who’s with me?”
“I need to seal off the Crystal Cave,” Merlin said dragging more books towards him. “Make sure this can’t happen again.”
“How do you plan on doing that?” Sam asked.
“I’ll think of something,” Merlin said. “It won’t be the first time I’ve made up a spell.”
“Can my sword kill an angel?” Arthur asked.
“It’ll kill Zachariah,” Dean said. “But not an archangel.”
“Good,” Arthur said. He straightened his shoulders and looked around the room. Grim, determined looks greeted him and he could almost feel the phantom weight of his crown. “Let’s get this over with.”
They spent the next few days getting everything ready. Plans were made and discarded while Merlin and Castiel traveled around the world looking for the ingredients Merlin would need for his spell.
The day they arrived at the cave it was mid afternoon. Arthur looked around, a confused frown on his face. Trees, lush and green surrounded them, the cave itself hard to spot unless one was looking for it. Sunlight drifted down through the canopy, lighting patches of leaf covered ground.
“I remember this place,” Arthur said as a hazy memory fought its way to the surface.
“You should,” Merlin said as he began to unload his supplies. Normally he wouldn’t need anything to cast a spell, but he wanted to make sure no one could abuse the power of the cave ever again. “You got shot with an arrow over there once.” Merlin nodded towards a narrow incline, surrounded by trees and rocky walls.
“What?” Dean asked, eyes wide.
“Oh,” Merlin said. “Don’t worry. This was back when he was still a prince.” He gave Arthur a glaring look. “I saved your royal ass then too.”
“Merlin.” Arthur had his arms crossed over his chest, Excalibur hanging at his side.
“You’re finally learning,” Arthur said. “And it only took you well over a thousand years.”
“Very funny,” Merlin said.
Dean came to stand next to Arthur and placed an arm around his shoulders.
“You sure about this?” Dean asked.
“Despite what I’ve said, Merlin does know what he’s doing,” Arthur said.
“I just don’t want you to get hurt,” Dean replied, voice rough with worry.
“And if we don’t do this,” Arthur said. “They’ll just keep trying. We have to stop it now before it gets worse.”
“I know,” Dean said. He took a deep breath and pulled Arthur into a hard hug. “I just don’t like it.” He held on for a moment longer before letting Arthur go. “I guess I just wanted you to have the life your uncle and I never got.”
“Oh sweet,” Zachariah said, voice dripping with insincerity. “Such a touching family moment. I think I’m going to be sick.”
The next instant they were all flung away from the cave and a bright flash of light caused his Uncle Cas to be banished. Arthur hit the wall of the gully, rocks digging into his back, his breath leaving his body. He tried to get back up, but another hit forced him back to the earth. When he looked up he saw his dad, held aloft in Zachariah’s hand. His Uncle Sam lay against the opposite wall. Arthur couldn’t tell if he was breathing.
“You wait your turn,” Zachariah said, a vicious snarl curling his lips.
A quick twist sent a loud crack through the air and he watched in horror as his dad fell dead to the ground.
A second later, Zachariah filled up his line of sight, a dark specter against the bright blue of the sky. He twisted his hand, and Arthur’s insides clenched, like someone had reached inside of him and was ripping his organs apart.
“You will full fill your destiny,” Zachariah said as he bent forward. Arthur could feel his breath ghosting over his cheeks, could see the madness lighting up his eyes. “It is what is written, Your Highness, now commit.”
“No,” Arthur ground out, blood dribbling from his mouth.
Another wave of agony ripped through his body, and he closed his eyes, rearing back as he couldn’t help the cry of pain that fell from his lips.
A far away part of his mind picked up movement, but the pain was too much. It clouded his thoughts, and narrowed his world down to just pain, and the blood filling his mouth, clogging his throat.
“Leave him alone.”
A blast of magic filled the area. It was so bright Arthur had to turn his head away from the sight.
His eyes stung, and his lungs burned, but he could breathe again. Opening his eyes, he found his sword nearby. His hand curled around the hilt and he struggled to his feet.
Merlin was in a standoff with Zachariah, eyes burning gold, hands held before him. No spells fell from his lips, just endless blast of magic against angelic power.
After a few missteps, he finally made his feet, sword in hand.
A blast of power sent Merlin tumbling to the earth, blood spilling from his nose.
The sight enraged Arthur, filling him with a fury he hadn’t felt since Morgana had tried to destroy him and Gwen. His dad was dead, his Uncle Sam wasn’t moving, he had no idea what had become of his Uncle Cas, and Zachariah was trying to kill Merlin.
He didn’t know how he covered so much ground so quickly, but the next thing he knew his sword was buried in Zachariah’s body, the tip angled towards the sky.
“You really shouldn’t have done that,” Arthur ground out, twisting the blade.
Zachariah’s mouth hung open, shock written on his face. Light began to bleed from his body and Arthur turned his head away, squeezing his eyes shut.
The resulting shockwave knocked Arthur back, the heat causing his skin to tingle. He hit the ground with a bone crunching force and the world went black.