Chapter Text
“You're not walking out of this cave with me, are you?”
It's a slow realization, and a heavy one. It’s always that way with Merlin though, and he struggles with the matter of breathing faced by the revelations of the weights the brunette behind him carried on his shoulders with a smile, all hard decisions in his name for years on end without his knowledge.
He thinks of what it took of him, to realize Arthur wouldn't make it, to turn from his course to Avalon and towards the crystal cave, using of his blood and Arthur's to reach back into time and into a second chance.
“All magic has a price, Arthur.” He sounds so serene, almost whimsical, and Arthur feels like a girl for thinking those things, but maybe it's just the fact that he is about to lose him. “I can't bend all laws of balance to my favor.”
“You did not tell me of this price. You did not say, it would be you.”
“It was me or you, sire.” He says, and it takes all of him to not smack him across the face when he listens to the smile in his voice, sucking a breath sharply as his Merlin’s finger reach to brush over the side of his chain mail where Mordred had ran him through, now only tender flesh and mended skin. “It's not hard to guess what my choice would be.”
He wants to cry, because it was true. He often forgot that Merlin drank poison for him two weeks into knowing him, tried it again after the unicorn, and now the list of almost deaths was so extensive it was hard to keep track once he knew them all. The softly whispered confession of Merlin's voice had been his one distraction in the arduous way through the cave. Poisons aside, he had struck a bargain for Arthur's life with his, he fought and killed Nimueh, he fought Morgana countless times, he was captured by a troll in the dungeons, Alator, there had been the Lamia, the fomorroh, the dorocha, and so much more.
The walk through the cave was long and arduous, and after they — well, Merlin — had opened the portal through the core crystal, it has been dark and cold. Merlin had warned him he could not turn around, because if he looked behind him, to the future they were abandoning, they'd be back into the cave, he would bleed to death in Merlin's arms, and everything would have been in vain.
Still, time was a funny thing in the cave. Merlin said objectively there had been barely a few hours between the moment they had walked in and now, but it felt like months. Had he been alone, Arthur would surely go mad, but he wasn't. He demanded his truth, and Merlin told him, easily and freely — too easily, too freely — and he should have known.
Merlin was born with magic, he was the warlock of a prophecy regarding Arthur, he was the most powerful warlock to ever live, he was meant to protect Arthur. His father had been Balinor, he had loved a girl once, the girl had died. Will hadn't been the sorcerer, he had. Lancelot knew, because he has enchanted his spear. Back then, he had planned to be the sacrifice, but Lancelot had gone ahead and spared him.
Arthur couldn't be more thankful and, even though he couldn't look back, he reached for Merlin's hands and the warlock interwined his pale fingers with Arthur's. His hand was colder than usual, but warmer than the cave. Merlin had whispered his biggest confession so softly Arthur has barely heard it over the heavy thumping of his heart. How a small, magical nobody of Ealdor had loved the Prince of Camelot for as long as he could remember. He had had to stop, to kneel in the damp ground and let the stupid man hug him from behind, holding onto his hands and arms as tightly as he could, sobbing out of heartbreak and joy as he told him about a King who had once been a Prince and who realized he loved a stupid, brave and selfless boy in the moment he had seen him on a bed, dying from a poison he willingly drank for him.
‘All this time and you never told me?’ Merlin had whispered, chuckling softly though his voice too had been heavy with tears. ‘Who are you to say anything?', he had retorted with a snort, ‘You've magic and you've been in love with me too, you're the bigger fool.’
Merlin's lips had brushed his shoulder as he pressed the words, warm and meaningful against his chain mail.
'The best kept secrets of Camelot.’
Time was a funny thing in the cave. They had confessed their love merely moments ago, he knew. It has been sweet and warm and glorious, and Arthur had never been as happy, not even when he married Gwen, not even when he saw Merlin defy death to return to him time after time.
Now he felt like he had never been as unhappy. The tears that sprung to his eyes once more were not of joy. He felt like he might die at any moment.
But he wouldn't die, because who would die would be—
“I should have made you swear.” He whispers, voice and breath shaky at his innocence, his stupidity, his naivety in believing Merlin’s words. “I should have made you swear you wouldn’t put my life above yours, I should have made you swear you would be safe.”
“Old habits die heart, my King. Don’t hold what I chose to do against you.”
“I’m holding this against the both of us.”
The mouth of the cave was just ahead, and it was light and bright and wonderful, glowing with promises. And he didn't care for a single one of those, because Merlin wouldn't be with him. He lets his head hang forwards, limp and defeated and strangling all his words inside.
“Arthur." Merlin's voice calls, through the haze of cold and the devastation of death. He lays his forehead against Arthur's back, in-between his shoulder blades when he refuses to turn, blinking the tears from his gaze and holding his head high. “Arthur.” Merlin pleads, forehead still against his back, long fingers holding tightly onto the king's arms, before he lifts his face to press a kiss to the back of Arthur's neck and noses along his hair. “Turn around.”
His breath gets stuck in the back of his throat for a moment before a mournful sound rips itself out of his lungs. He knows what he's asking, he knows what this means, he knows what will happen and he won't do that because if he does that—
“You will leave me.” He moaned, shaking his head and trying to pull from his grasp, to guide them into the light, to keep Merlin. Gods, he just wanted to keep Merlin. “If I look at you now, I'll walk out of here alone. You'll leave me.”
“Arthur..."
“Merlin, I cannot do this alone!”
“You won't be alone. I'll be with you, I've always been with you.”
“But he is not you.” He screams and his voice echoes, loudly. “I mean, he is you, but not this you. He does not know what happened, he won't know.” A shaky hand hovers above his and he squeezes tightly, hoping that if he holds him tightly enough he will understand. “He won't be you ”
He just wants to keep Merlin.
Can't he be allowed that?
“No, he will be better.” No one could be better, he doesn't want him to be better, why can't he see that? Why can't he see that? “When you tell him, he'll be frightened for a moment, but he won't be scared.” And he can hear in-between his words, ‘he won't be scared as I was’. “He won't grow skeptical and cynical, and he will know you care for him. And above all else, you will be you.” Merlin places his palm over his chest, right above his heart, a heart that should not be beating, and that will keep it's pulse if he doesn’t looks back at the expense of Merlin’s. “You're all I ever needed to be great and brave, Arthur.”
“I don't want you to be great or brave. Lord knows you already are too much of both to your own good.” He murmurs, holding his hand tighter, still refusing to look back at him, blue eyes and earnest face. “I don't want you to change, I just want this.”
He feels the ghost of Merlin's smile against the side of his neck.
“You are all I ever needed to love you too. It's true now, and it was true back then.” Arthur closes his eyes and waits for the other shoe to drop. Merlin can't just be sweet, he has to be an ass about it, call him a prat or something. “Hell, I know that I'll be happy to not have to wait as long to kiss you.”
The grin is involuntary, it's just his natural response to his cheekiness.
“Shut up, Merlin.”
“Not a chance, sire."
Time was a funny thing in the cave. They could have lived a lifetime here, he thinks. He feels stronger by the second, so he can hold tighter on Merlin's hand when the other's grip falters. It's hard not to wonder what a lifetime shared with Merlin would be like, even in here, even if he couldn't crown him, even if he couldn't see him.
His voice would be enough, his presence would be enough, the knowledge that no harm could reach him, even if the safe nest he had found is a long black corridor of stones and magic that he could barely see a palm ahead of him for the longest time.
And there, in the cold, hopeless dark there is just the same old temptation, whispered in a beloved voice, soft with defeat and heavy with premeditated loss.
“Turn around, Arthur.”
He's just too close to breaking, and if anyone in the world knows how to tempt a Prince of Camelot, it's Merlin. So he shuts his eyes and makes sure he can't see a thing as he turns to him, hands traveling up to his face before his lips move to steal any other traitorous words he might say from him, take his breath and give him his, until all they know is that perfect limbo where all that exist is them.
Time was a funny thing in the cave. He could have kissed Merlin for a millennial, and still it wouldn't feel like it had been enough. The kiss stretches into an eternity that sets fire to his chest, warms his heart and burns his lungs, and he needs air but he also needs Merlin, so he pushes a little more. The fool tastes of blueberries, and he can only picture how many he stole from his plate when delivering him meals. His hands holds onto Merlin's hair and he can't say which of them lets out that needy noise, but the need is mutual.
Still he needs air. Cursed air. He breaks the kiss, forcing himself to keep his eyes closed and leans his forehead against Merlin's, noses his cheek and along his jawline and down his neck. The cave echoes with their heavy breathing.
“Please, don't leave me.” He pleads again, and he hopes, he prays that this time he will listen.
Instead, Merlin presses his face against Arthur's, and breathes like he needs to strengthen himself for the moment they are to face.
“Find me, and I'll never leave you again.”
It's a promise, he knows, but it's not the one he wanted to hear. Still, Merlin hugs him, pulls him tightly against his body, and, finally, he gets his wish, because as Arthur hugs him back, this side of desperate, his hand finds a warm moistness that is too familiar. Arthur opens his eyes in horror, scarlet stained hands moving to hold onto Merlin's arms, to put some distance so he can try and make sense of what's happened.
“Oh my God.” He lets out, breathless and gutted.
He is smiling — heaven knows how this man can still smile, despite everything — and the smile seems to show how hollow his cheeks have grown, skin sinking in the places flesh is lacking. He's thinner, so much thinner, and cold as death. On his side, directly opposite to the one Arthur walked into the cave clutching so his insides didn't fall out, Merlin bleeds his life away as if that didn't hurt at all.
That's when Arthur realizes: the magical explanation was bullshit. Merlin just couldn't let him turn and see the sacrifice he was committing even as they walked. He had traded his life for this spell, and he had traded his health for his and he could not bend the laws of magic to not demand their price.
Blue eyes start to glow golden, and he sinks his fingernails in the too-fragile shoulders.
“Merlin—”
“Rhethoen toa.”
He tries to scream, but it's like he's being blown away, torn from Merlin and into the blinding light
When his eyes open again, he's laid on his bed, years in the past, and a younger Merlin is opening the curtains with a bright smile.
“Rise and shine!”