Nimueh could feel Merlin's agony from miles away. Had their been any human part of her left, she might have felt pity; as it was, she felt only a twinge of distaste.
"Disappointing," she sighed, lounging over her fount and watching the black dragon careening through the air. Suddenly she straightened, frowning. She could feel Merlin disappearing. His essence was fading, ebbing away; in a moment or two he would be gone. He was not dying, so why-
"It isn't your time, my pet," she tutted, and her lacquered nails dipped into the fount, turning the water a swirl of gold and blue and deep, inky black. "I can still use you yet."
Aithusa was used to being a caretaker. She had always watched over Morgana, and now she watched over Emrys. It took many moons to nurse him back to health, and the entire time, he said very little. He only watched her with his strange, sad eyes.
He dreamed often. She would wake to hear him mewling softly in the dark, his tail snapping between the trees, and when she woke him his eyes were for a moment lost and alien- not Emrys, she thought, but the moment always passed too soon and he would huff at her quietly before settling back into sleep. Even as his wounds healed into scars his dreams did not cease.
Aithusa herself slept very little for the first few weeks. Her mind was constantly in turmoil. On one hand, the black dragon had killed Morgana; it had not been Emrys, to be sure, and maybe not Merlin either, but the stain of murder lingered. Some part of her felt that she was doing her mistress a great wrong by taking in her killer. Even so, she could not destroy the dragon. She could not even abandon him. He was small, and permanently weakened by their battle- his wings flayed, his face and body sadly scarred. Everything about him seemed vulnerable. The need to protect him was downright primeval, but even stronger than this need was Aithusa's own need for companionship. She had never been alone, not really. To be the last of the dragons... How could she turn out the only other of her kind?
There's someone in my head someone in my head
Dark. Snatches of light, of sound.
But it's me in their head how can this be I'm me I'm Merlin this isn't right
He was watching through a glazed pane refracted a thousand times over, meaningless colors and shapes.
I wanted it to be over this isn't what I wanted this isn't right
There were brief intervals of clarity; he did not know it, but this was when Emrys dreamed. He waited for these moments, desperate to understand what had happened, to understand why he, Merlin, had not died. He existed as a shadow. The absence of feeling was what struck him the most. He had thought that that was what he wanted- not to feel- but the emotions were still there; no, they were all that was there, because there was no hot, no cold, no tiredness, no pain. Maybe he had died after all, but now he was a ghost, consigned to wander a place without form or dimension. There were only his memories, now crystal clear without anything to distract him. And the tiredness was still there.
As time passed he learned to see through the distorted light of the world beyond, somewhere outside of him. The images were vague at first, but he understood that he saw as Emrys did, and occasionally felt as he did, too. It was a secondhand excuse at life but anything was better than the thoughts in his own head and so he watched.
He saw Aithusa often, although she only saw him for the briefest of moments- when Emrys was asleep, dreaming, and he had not yet shuffled Merlin away as a nightmare. He could not speak in these moments, although he tried many times, and eventually he learned to enjoy that single second before he drifted away again. And that's how it was- drifting, floating through a darkness so complete he felt disintegrated, a particle in the deep. Sometimes it was even peaceful. He was never happy, not really, but more and more often he stole a piece of vicarious happiness from Emrys. It was obvious that he and Aithusa were mates. Neither of them knew it yet, as was a dragon's wont; they only understood that they knew each other from some time long ago.
Dragons only mated once, Merlin knew, and he had heard a story as a boy that the reason for this was that they were created in pairs, their eggs formed in the stars but falling down to earth at different times. A dragon could wait centuries for their mate, but they would do so patiently. There was no stronger bond. And now Emrys had found his.