The two dragons stared at each other, heads half-lowered like dogs. Arthur felt a twinge of uneasiness. Merlin was dwarfed by the white dragon, standing at maybe half its size, and was far more slender.
"My, Emrys… You certainly have changed." Aithusa's lips never moved and yet the sound of Morgana's voice echoed through the clearing.
As have you. Only Arthur could hear Merlin's response.
"And how sweet. You brought your boy king with you." She laughed, blinking coquettishly and taking a step towards Arthur. The black dragon snarled—a deep, rumbling sound, like thunder, and Morgana pulled back slightly. "Don't worry, Merlin, dear. His death will be quick. I only wish I could say the same for you."
Her jaws seemed to unhinge and a current of fire roiled out of her mouth and towards the knights. Merlin, impervious to the flames, stepped in front. His wings spread as shields and the blaze bounced off of the membrane, but Morgana seemed to be expecting as much. The moment the flames had left her tongue she dove forward, her front claws scrabbling for purchase amidst Merlin's scales.
The black dragon howled, staggering backwards under her weight, and Arthur could see his hind legs flexing desperately to avoid crushing the knights. Droplets of blood oozed from his shoulders, where Morgana's talons had sunken into the skin. At that moment Percival ran forwards, screaming in fury and holding his sword aloft.
"FOR GWAINE!" He shouted, and struck against the white dragon's chest. The blade did little more than bounce off of Morgana's scales, but it was distraction enough for Merlin to free himself and stand, glowering, in front of the knights.
"Gwaine?" Morgana laughed. "Surely you don't mean the cowardly little man who betrayed your king."
Her words seemed to galvanize the black dragon, and he leapt at her with such force that several of the men standing behind him were pushed backwards. Two men ran at his flanks.
Kilgharrah had said it was a thin line.
Merlin had heard Morgana's voice and shapeshifted instantaneously, without a thought, but the more she spoke, the less he understood. There were no words, only sounds—familiar sounds, but sounds without meaning. Two of those sounds stood out in particular.
The first was a threat against the man he needed to protect, the man that called him Merlin, whose aura shone like a star. The second time was about another man. A different man, one that used to be very dear, and suddenly Emrys became aware that this priestess had killed him. He was overcome by rage. He didn't remember the man's name, or his face, but he remembered an aura not unlike Arthur's—bright and warm. Kind. There was a memory in his mind; it wasn't his (it was Percival's, but Emrys didn't know this), but it was vivid enough. It was the sound of screaming.
He sprung forward, his jaws snapping in the air. They closed about the white dragon's neck, but he couldn't land a fatal blow through the thick scales. She cried out in surprise and anger, and thrashed fiercely beneath his grip. Emrys caught sight of two of the knights, who were slashing with swords at Morgana's flanks and midsection. One of the men seemed to be having very little luck, rebounding off of her glimmering hide with every strike, but the other wielded a much different blade. It was the man with the shining aura, and the weapon he carried had a name. Excalibur.
The sword slid effortlessly into Morgana's back leg, and she roared, sweeping at the man with her tail. He was flung into a tree trunk with one powerful strike and Emrys half-turned instinctively, wanting to see if the man was hurt, and unconsciously he released his grip on Morgana's neck. The moment the pressure of his teeth lightened she heaved against him and he fell onto his back, his wings pinioned beneath him.
The entire clearing seemed to shake with the force of the two dragons hitting the earth, and Emrys realized he had come within a few yards of landing on the knights. It wasn't safe to fight on the ground, not with the fragile men, and even as he felt sharp talons searing through his exposed underbelly he surged up, off of the ground, and took to the air.
Morgana had been thrown off of the smaller dragon when he jetted upwards, and as hoped, she ignored the knights completely in favor of her departing enemy. She took off, leaving Arthur, Percival, and the others to watch from the clearing.
Despite having smaller wings, Emrys did not have the girth of his counterpart; he was lither—built, it seemed, for speed. Morgana could only just keep up, but the sound of her snapping jaws at his tail urged the dragon on faster. He had no idea where he was going, only that his chest and shoulders burned and that he had to go in the opposite direction of the castle, and suddenly a voice rang through his head.
Merlin. Listen to me.
For a moment the voice was strange, almost dream-like in its unrecognizable familiarity.
Your name is Merlin.
He understood these words, but it didn't make sense. His name was Emrys.
You cannot forget yourself, young warlock. You must fight it.
"Kilgharrah?" Emrys said, and he was Merlin, and a surge of fear gripped his heart. "Did I—"
I told you it would be difficult to keep hold of your human self, but it should have taken decades to reach this level of lethe. There is another force at work here. Someone powerful. You should change back, Merlin, and soon.
Merlin turned his head. Morgana was still flying after him but had fallen back a ways, and when she saw him turning she sped up with a high-pitched cry.
"Kilgharrah, I've barely been a dragon for a few hours. I don't know how to fight her."
And how long have you been a sorcerer?