How To Train Your Dragonlord

The End of Season 5 and How It Changes

Mordred had stabbed Arthur. Merlin raced straight to Arthur, ensuring that he knew the healing spell off by heart. Merlin had been keeping an eye on Arthur fighting, scared that something would happen to him. Mordred had taken Excalibur from him and, stupidly, thrown it onto the ground, away from him. Then, he had stabbed Arthur with his own blade. Merlin cursed happily under his breath because Arthur would be okay.
As Merlin reached Arthur, Arthur started to fall to the ground. Merlin cast a spell to ensure that Arthur fell into his arms. Arthur held onto Merlin's arms, believing that he would die. “Merlin,” he started. Merlin shushed him.
“You're not going to die, Arthur. You'll be okay,” Merlin promised his king. Arthur opened his mouth to ask how Merlin knew. “For one thing, it wasn't Excalibur that he used on you. He used his own blade…” Arthur was glaring, wide-eyed, behind Merlin. Just in time, Merlin turned to see Mordred run at him with a blade.
Calmer than he'd ever felt in his life, Merlin lifted a hand to push Mordred away. As the blade came down, not towards Merlin but towards Arthur, Merlin was forced to change his plan. Instead of pushing Mordred away with a spell, Merlin was forced to kill him, to protect his king. This was because, while he was a warlock and a druid, his first loyalty always had to be towards King Arthur Pendragon.

Arthur saw everything. Merlin was above him, reassuring him that he wouldn't die. He saw Mordred approach and warned Merlin with his eyes. It was strange when Merlin turned around, though.
He saw Mordred and put up his hand, stretched towards the traitor. Then, Mordred's blade started to come down towards Arthur. Merlin's body tensed and, as it did, Mordred fell back, the life disappearing from his eyes. The blade fell down to the ground beside his body.
For about a second after Merlin had turned back to face Arthur, his eyes retained the golden colour of the eyes of someone who had just performed magic. It was there for just a second and then gone. But Arthur knew what he had seen.
His complexion paled, partially from the shock. His blundering idiot of a manservant was actually a very powerful warlock. “M... Merlin?” he asked, stuttering.
“Yes, Arthur,” Merlin replied, knowing what Arthur was trying to ask. “But, Arthur. I only use it for you, for Camelot. And I know a healing spell that will help you. After that, you can banish me, or even burn me on a stake, if it'll make you feel better and safer.”
Arthur lay there, not speaking or even thinking. He just lay there, disbelieving, waiting for Merlin to heal - or kill - him.
Merlin started to chant something under his breath. Immediately, Arthur felt a tingling sensation throughout his body. He saw Merlin's eyes shimmer from their normal blue, to the magical gold colour as he chanted. He looked down to where he'd been stabbed. The wound was disappearing, almost gone completely.
Once the wound had completely disappeared, the king's astounded gaze returned to his manservant. Merlin's eyes were blue-green once again. As Arthur looked up at the eyes of his manservant, he saw only adoration and respect and concern for the king in Merlin's eyes.
Even if he had been considering persecuting Merlin - which he hadn't - after seeing the amount of devotion that he did in Merlin's eyes, Arthur's conviction that not all magic was bad was firmly reinforced. And anyway, the man had just saved his life, after all.