Disclaimer: I have no idea who owns Merlin ©, but I do know that it's not me!
Way 1: Burnt at the stake
Merlin walked up the steps, resigned to his fate. He'd always thought that it would end this way. He'd hoped he was wrong, but when yet another vengeful sorcerer attacked the court of Camelot in the middle of a feast, there really wasn't much choice. Now he was going to be burnt at the stake for saving half the nobility of Camelot.
"Have you any last words, sorcerer?" Uther demanded.
"Warlock." Merlin answered. Uther looked confused, and Merlin rolled his eyes. "I am a warlock! There's a difference!"
"Are those your last words?" Uther demanded.
Merlin sighed. "No, they're not." He turned to Arthur, and for a moment, he could swear his friend wanted him to die just as much as Uther did. But then the look softened, and he saw the pain in Arthur's eyes. "One day, you will be a great king, Arthur. I know that, even if no one else does."
Arthur blinked, a look of confusion on his face. Merlin smirked, letting him know that the serious bit was over. "Remember not to get a bootlicker for a servant. You're going to need someone to shrink that enormous ego of yours." Merlin's smirk dissolved into a smile a look of comprehension crossed Arthur's face. "And try not to be a such a prat."
"Begin the fire." Uther ordered.
Arthur turned to his father. "Father please. We owe him better than this."
"You have already made your agreements known, Arthur." Uther answered. "And I will repeat what I had told you then. Sorcery is a vile and evil action, and must be punished in a manner as severe as its practice."
"If you speak again, I will have you placed in the dungeons." Uther interrupted. "It is obvious that this sorcerer has enchanted you to believe in him."
Arthur ground his teeth, forcing himself not to attack his father. He turned down to Merlin, and felt the utter hopelessness of the situation. I'm sorry. He mouthed. There's nothing I can do.
Merlin gave him one last goofy grin, and Arthur felt his chest freeze up. For a long moment, two pairs of blue eyes locked. Then Merlin disappeared behind a wall of flame. Arthur closed his eyes and waited for the screams.
That's when it started to rain.
And not just any rain. Great giant raindrops the size of buckets dropped from the sky. In just minutes, the fire had extinguished itself, and a rather drowned looking Merlin looked up from the pyre. "Um. . . can someone get me down now?"
Arthur let out a relieved sigh, and he saw a hysterical look of relief on several faces in the crowd. Merlin just looked shocked. After a few minutes, the rain died down. But it had done a perfect job at saving Merlin: the wood was soaked. Lighting it would be completely impossible. Arthur caught Merlin's gaze and couldn't help a grin.
Apparently, the gods didn't want Merlin burnt to death today.