Warnings: Major character death, minor character death, temporary character death, violence
Disclaimer: I do not own the BBC version of Merlin; It and Shine do. I am very respectfully borrowing them with no intent to profit. No money has changed hands. No copyright infringement is intended.
Author's Note: Some dialogue from the first part of the story is from the Merlin episode, The Diamond of the Day part 2, by Julian Jones.

Phenomenal Beta Reader: Her name is Camelittle and she's amazing. She whipped me into shape. When I was stuck, she sent lots of suggestions, and while I didn't use them, it didn't matter because they were awesome ideas! She was a cheerleader, too. Thoroughly enjoyed working with her. She did a fantastic job as beta reader and all-round terrific brit-picker. Any pesky mistakes you might find are mine!

Amazing Artist: texasfandoodler is just so darn good. I don't think I'd have finished if not for her inspiring artwork! You should give her all the love since her artwork is amazing. Plus she was so terrific to work with that I haven't words to say about how great she is. Try and see her work. It is on archive of our own under texasfandoodler. Title is 7 art pieces for After Camlann Big Bang story - Promises to Keep. Or you can search AO3 with this number. 4629858

Chapter 1

It was all his fault. There had been the relentless call of destiny and yet no matter how much Merlin had struggled against it, in the end, his choices, his lies, his fear had led to Camlann.

And Arthur paid the price for it.

With Excalibur still clutched in his hand, he lay among the litter of dead bodies, men he'd killed for Camelot, and next to him, young Mordred was sprawled, an unmoving corpse.

Merlin couldn't breathe. His mind was insisting that somehow if he didn't move, if he could keep time frozen at that moment, it would not be real; Arthur would still be alive and he'd be able to save him.

But of course, that was absurd.

Around him, Merlin could hear Camlann's battle raging on but he ignored it, ignored the gore and savage chaos around him, the screams, the murderous clang of swords, the stench of bodies ripped apart. Entrails and vomit and death.

For Merlin, there was only Arthur.

Even as he stared down at him, he was praying to whatever gods would listen to him that he wasn't too late, that he could still fix it all somehow. He would do anything, kill a hundred enemies, a thousand, give up his own life if only Arthur lived.

But the gods were silent. His destiny was lying there, among the corpses, exhaling harsh pain into the night sky.

Moaning.

Moaning….

He didn't remember kneeling down but when he placed his hand against Arthur's neck and felt the slow reassuring thud of a heartbeat, Merlin knew he could finally breathe again.

There was still time to make things right.

In the distance, there was a great roar of triumph. It sounded as if Camelot's forces had won at last but the fighting was not over yet and Merlin shuddered, realising that he had to get Arthur away before the Saxons found them and ended his king's life once and for all. Gathering him up, slowly placing one foot in front of another, Merlin turned past the carnage, past Mordred's dead eyes, past enemies and friends and Camlann.

By all rights, he should have gone straight to the medical tent where Gaius and the others would be tending to the wounded. But he knew if he did, if he surrendered Arthur to them, to the knights and nobles of the court, they'd have kept him away, probably would clap him in irons and shove him into the nearest, deepest pit. They would certainly try to prevent Merlin from using magic on their king.

Sorcerers were still not welcome, even ones who had saved the battle for Camelot. It was Merlin's fault after all, Merlin's shame that they weren't accepted, even revered. It had been his bone-deep fear that led them all down the path and only now, gathering his courage at last, he knew he'd have to right it, even if Arthur rejected him in the end.

But there would be no salvation for Arthur in the medical tent. Magic was the only force that could still save him now.

For it was sorcery and not a simple blade's thrust that was destroying the destiny they'd forged together. An ordinary wound would have been easy enough to heal; instead Merlin could feel the wrongness deep in Arthur's chest, the red malevolence that seemed to pulse, pulse, pulse with every beat of his beloved king's heart.

So he took one step away from the battle and another, holding Arthur close to him. He tried not to jostle him too much, watching where he walked in order to make sure his clumsiness didn't get the better of him, all the while worrying about blood loss and pain, about making things worse. He whispered healing spells over and over again, hoping that somehow his magic would be able to overcome whatever Mordred's blade had destroyed, hoping that a thousand spells spoken with love and longing would heal him.

After all, Merlin was supposed to be a sorcerer, the greatest of them all, and what good was it if he couldn't help Arthur?

And yet still nothing changed. Arthur was not waking, not healing. Dark magic raging against the light and the dark forces were winning.

But desperate, despairing, it did not stop Merlin from trying again and again. And again.

It was quieter in the woods. Laying Arthur down onto the cold ground, unwilling to leave him even for a moment, with a flick of his fingertips, firewood gathered next to him, stones rolling into a neat firepit —Merlin would have smiled if it hadn't been so dire, and a breath later, a fire was burning brightly beside them.

Exhausted, Merlin knew that he couldn't stop. Arthur needed him, now more than ever. Resting his hands upon the wound, he tried to draw out whatever Mordred had left behind in Arthur's chest, putting everything of his magic into the command. "Yfel gæst, áfierre þu fram þisnelíchaman."

But although the wound has long since stopped weeping blood, the wrongness continued and nothing emerged. It was still trapped in there, embedded deep within Arthur's body.

He had no idea what to do about it.

But Kilgharrah might. Sending out a mind's cry, he called for the dragon to come, to help him, to lend him enough magic to heal Arthur. Again and again he shouted out into the night but there was only silence. Kilgharrah did not come and Merlin was left to try anyway.

He pulled up Arthur's chainmail, taking care not to jostle him too much, undoing the quilted gambeson underneath and the thin shirt. Arthur's skin was ragged around the wound but although it looked horrible to Merlin's eyes, there was no stench of destroyed bowels, only the tang of dried blood and sweat.

A dozen more healing spells, each more frenzied than the last but it was to no avail. There was no change, no dragon coming to rescue them, nothing but Merlin's magic, and even that was useless.

He sat back, face wet with tears, watching his Arthur's chest slowly rise and fall and knew it was his fault - for everything. His choices, his decisions had led them all to this and now Arthur lay dying, despite his best efforts.

He should have taken Arthur back to Camelot after all. At least there, he might have had a chance.

But something must have worked. Arthur blinked, his eyes unfocused, and as he moved, his face twisted into agony. "Mer..lin?"

Pushing him back down, Merlin smoothed one hand over Arthur's cheek. "Lie back, Arthur, rest." When Arthur just looked up at him, questions in his eyes, Merlin said, "The battle is won. Morgana's armies are destroyed." Arthur seemed satisfied with that, nodding at the news, but Merlin was tired of lies. It had only brought them both pain. He leaned in, his face wet with tears, and said, "But I should have stayed with you. I knew Mordred was the real enemy and instead I defeated the Saxon hordes, chased away Morgana's dragon. I thought… I thought it would keep you safe but I failed. I failed you so badly, Arthur. I am sorrier than you can ever know."

He couldn't bear to look at Arthur at that moment. The war was lost if Arthur didn't survive; Merlin would be lost, too. It was all he could do to keep from raging at the sky.

"It wasn't you. It was that old man, the sorcerer. He defeated them." Arthur gave another hiss of pain and then he said, "The sorcerer."

Shaking his head, unable to bear it a moment longer, knowing that if he didn't speak up now, he never would, Merlin said, "It was me. It was me. I am a sorcerer. I have magic."

The look of confusion on Arthur's face would have broken Merlin's heart if it wasn't already shattered. "You are not a sorcerer. I would know."

But Merlin could not let it go. It was past time Arthur knew the truth, even if he hated Merlin for it. Pulling on his magic, he lifted his hand and said softly, "Upastige draca!"

The spark dragon hovering above the fire was beautiful, joyously wheeling in flight and he'd hoped Arthur would see just how wonderful magic could be but as he turned back to Arthur, there was only fear and utter betrayal in his eyes. Merlin's heart broke all over again.

"Arthur, please, you have to understand."

Pain twisted in Arthur's face as he shuddered back away from Merlin's touch, as if he couldn't bear to be near him, as if Merlin had somehow defiled their friendship with sorcery. He must have seen magic as a pestilence, a plague meant to strike at the heart of Camelot, and Merlin nothing but a traitor for practicing it.

Arthur frowned up at him, looking as if he'd never wanted to see him again. "Leave me."

He'd wanted to explain, but there was nothing to be done once Arthur used that tone. They both knew that Arthur wouldn't change his mind, not this time.

Merlin had failed — at everything.

Chapter 2

How Gaius found their encampment Merlin didn't know. But a hurried conversation confirmed the worst. Arthur would die unless the blade fragment inside him was removed.

When Merlin pressed him, Gaius just shook his head, claiming that it was beyond his knowledge of medicine and perhaps beyond Merlin's magic as well. Only the dragon or the Sidhe were powerful enough to defeat the dark magic - and Kilgharrah still wasn't answering Merlin's call.

Arthur protested, of course. He wanted nothing more to do with Merlin and certainly nothing to do with magic, piling stones of guilt onto Merlin's chest with every contemptuous word. But Gauis was persuasive and Arthur's long history with the physician was enough for him to agree to try.

Merlin wasn't sure if it made things better or worse.

It was difficult.

Arthur's stubborn silence, punctured at times with soft pain-filled murmurs - as if Arthur was trying to keep his weakness from Merlin, didn't make things any easier. He kept up with the healing spells, whispering them into the air where Arthur couldn't or wouldn't hear them, hoping somehow they would work. But aside from the absence of blood and the sometimes-easing of Arthur's agony, Merlin knew they were running out of time.

The travelling, too, was hard on them both. He could feel Arthur's contempt when he dispatched Saxon bandits or hid their trail with tricks and magic. Once in a while, Arthur would let something slip, their old relationship trying to reassert itself but then he'd shut down again or make some cutting remark that he knew would hurt Merlin, a deliberate attempt at keeping him at bay.

Things came to a head later that evening. As Merlin took off Arthur's boots, setting them near the fire to dry them out, and then dishing out the stew he'd prepared, Arthur shook his head, saying, "Why are you doing this? Acting like a servant when you have magic? Hiding behind that stupid grin and idiotic demeanour? Is it a ruse? Getting me to trust you while you were stabbing me in the back?"

Underneath all the belligerence and accusations, there was a hurt tone in Arthur's voice that made Merlin ache with grief. "Is that what you think?"

"Why else? We've had enough sorcerers trying to take over Camelot. Perhaps your way is just more subtle, unbelievably hard as that is to accept. You do the idiot act so very well."

The insults were so familiar that, for a moment, Merlin couldn't help but protest. "It's not an act!"

Arthur started to smile at that but quickly turned sullen. Holding himself still, he scowled up at him, then turned away, a clear dismissal.

But Merlin wasn't having any of it. They'd lost too much time talking past each other and for once, he wanted Arthur to know the truth. "I've saved your life so many times I've lost count. I've not done it for money or glory or to take over Camelot. I did it because I know you are a fair and just king, even while being a complete and utter clotpole." When Arthur blinked up at him, looking furious, looking as if he didn't believe a word Merlin was saying, he sighed, accepting the silent rebuke. "I know you think I've lied to you and I have. I've been a coward and now you are paying the price. I should have confessed about my magic long ago. If I had, maybe you'd see that magic is just as much a part of Camelot as the air we breathe or the water we drink or the fire that warms us at night."

"Magic brings nothing but misery." Flat, dismissive, as contemptuous as Merlin had ever heard him.

His anger flared. Arthur really could be an incredibly stubborn arse at times. "A sword brings misery, too, but I don't see you giving it up. Because it can be used for good. Just like magic."

When Arthur didn't say anything else, just lay there glaring at him, Merlin nodded, then placed his hand under Arthur's head and lifted him up enough to spoon stew into him. He didn't want the bloody dollophead to choke after all. "You want to know why I'm doing this? Damn it, Arthur, you are my best friend and I don't want to lose you. So eat up and save your strength. We've a long way to go." And then he shoved the stew into Arthur's open mouth.

But Arthur must have listened, at least a little. Scowling most of the time, tight-lipped and silent, he kept watching Merlin, but it wasn't always hostile, and once in a while, there was even a thoughtful, almost accepting look about him.

Hoping the frost between them was thinning, even a little, knowing that it might be his last chance to make things right, Merlin began to talk of his life in Ealdor. Growing up, he had such a lonely existence with only Will and his mother knowing the truth and it had become impossible to find his place there. Coming to Camelot, he'd had such high hopes of learning to control his gifts. And then there was that first awful day when he realised the dangers of having magic. He told Arthur of his initial pique of being passed off like some kind of present to a princely prat and then a growing sense of rightness about it. Of protecting a royal arse who had an unearthly ability to attract trouble. Of Nimueh's bargains and Kilgharrah's lies. Of Balinor and failure. Of his belief that Arthur was a friend, no matter how much he might deny it, and his beloved king. Of their destiny together and his hopes for the future.

It was only when they rested, an increasingly frequent occurrence that alarmed Merlin more than he could say, did Arthur finally let him in.

"Why did you never tell me?"

It sounded as if Arthur was trying to keep the hurt out of his voice but Merlin had known him too long not to recognize what he was trying to do. In a way, it warmed him. It meant that Arthur might have even started to forgive him, just a little.

He tried to smile but the remembered ever-constant dread of the last ten years was still lurking just beneath the surface as he said, "I was afraid you'd cut my head off."

"I'm not sure what I'd have done."

At least Arthur didn't lie about it. After all, in the early days, he probably would have sided with Uther and watch Merlin be executed; he'd arrested Merlin for it more than once. But knowing that he might have had forgiveness if only he'd said something before it was too late, made his chest ache.

"And I didn't want to put you in that position." It was not quite the whole truth but close enough.

"That's what worried you?" Arthur shook his head, rolled his eyes at the idea. "You really are an idiot."

Merlin only shrugged. There weren't enough words to tell Arthur of how living every day with the knowledge that it might be his last had warped him, changed him from a sunny foolish boy to the man he had become.

Maybe he didn't need to. Arthur could always read him well enough, except perhaps for the magic. If they were able to make it to the Lake of Avalon and the Sidhe cured Arthur, perhaps there would be time enough for both of them to heal.

Then it was too late.

Morgana found them somehow. After chasing away the horses and then snarling at them, gloating about it all, she threatened them both with a long slow death.

It hurt to listen. He wanted to help her, even then; he'd hoped to redeem himself by bringing her back to the light but when she stood there over Arthur's body, spilling out her poison, she made him realise at last that there was nothing more Merlin could do. In her madness, she'd never let them live in peace. She wanted Arthur dead, wanted it more than power or honour or love.

So while she talked about watching Arthur die, laughing when Merlin threatened her with a sword, he stepped closer. With one thrust of Excalibur, taking on another guilty burden, he ended her life.

If things had been different, it might have been a relief. With her gone, there would be peace at last for Camelot.

But it didn't matter. Morgana had won.

Because the horses were gone and he had no way to get Arthur to Avalon in time.

Merlin was nothing if not stubborn. He would not let Arthur die, just because there was no way down, even if Arthur argued with him that they'd never make it.

Putting Arthur's arm around his shoulder, knowing that every movement was agony to him, Merlin began to walk, half-dragging him down toward the lake. Desperate. Desperate to reach it in time.

Arthur was growing pale, every breath seemed to weaken him and finally he'd had enough. Slipping out of Merlin's grasp, he sank to the soft grass and lay there, panting, his face twisted in agony. "It's no use, Merlin. I… it's no use."

Shaking his head, the fear that it might all fall apart shivering under his skin, Merlin knelt down beside him, tugging on Arthur's sleeve. His throat clogged with tears, he said, "You have to try. You have to…."

But Arthur just lay there, face white as a shroud, trying and failing to smile. His voice was weak, too, hardly moving the air as he said, "You have to listen to me. I'm your king."

"Never listened to you before." He pulled him closer, trying to lend Arthur the strength to go on but it was no use. "Please Arthur, don't give up. Please."

Arthur reached up, his gloved hand gentle against Merlin's cheek. "When I'm gone, don't let it change you. I want you to always be you."

Merlin was suddenly furious. He wouldn't let him die; it couldn't be the end of all they'd done together, all they were to each other. There was too much yet to do and the thought of doing it alone, of endless days without Arthur, terrified Merlin.

He said sharply, "No talk of going. The lake isn't far. I'll carry you."

Pulling at him again, he tried to lift him into his arms as he had done after Camlann, but Arthur just gave a sharp grunt, his face twisting in pain. Knowing that Arthur would sooner die than show weakness — and didn't that thought horrify him? — Merlin let him go.

"Enough, Merlin, enough." Arthur slumped down, boneless and fragile. "Just hold me."

"Stay with me." Merlin could feel the wrongness pulling Arthur towards unconscousness; the thread of life was growing thin, was stretching almost to the breaking point. "I won't let you go. I won't."

Desperate, he shouted up to the heavens, calling for the dragon one last time but still no answer. But it wasn't the end. He refused to accept that Arthur was taking his last breath, refused to allow death to pull him under.

Screaming that refusal into the sky.

"No!"

Rage building, building, without thought, he slapped the ground beside Arthur's body. A shockwave of power, blaze-bright, exploded outward. Wind thundered over him and up into the forest, a cyclone of destruction, with thick tree limbs snapping and a roar of shedding wood. The air itself filled with fire, rocks nearby crumbling into dust, the ground under him bucking like a frenzied thing. The sound of it all was deafening in an upheaval of anguish and fury.

If he had to feel such loss, then the world would feel it with him.

He bathed in it, the wild madness, an eternity roiling in anarchy and death. Letting it all go to hell, too afraid to look at Arthur and see his final moments, instead he was shrieking to the gods for some kind of miracle.

There was no reply.

Finally, he couldn't bear it any longer. With the chaos still raging above him, Merlin blinked away tears and looked down at the man to whom he'd given everything.

He wasn't moving. His king, his friend, was lying there, still. No breath, no pulse beating at his throat, no grimace of pain or helpless smile, no hand seeking his. No mocking retort, no calling him a girl one last time. Nothing.

Arthur was dead.

Throat raw from screaming, all Merlin could do was give a little sob and bend down and lay his head on Arthur's chest and rest there and wish that he'd died, too.

But he was not so lucky. Instead, he remembered all of his failures, knowing that they was his choices that had led to Arthur's death, and tried not to think of what to do next.

He didn't know how long he lay there, pressing himself into Arthur's unmoving corpse. In one small part of his mind not numbed with grief, he knew there was something wrong. Under his hand, Arthur's body was hard as stone, as unyielding as if he had been frozen in time.

When he could finally think beyond his anguish and try and wrap his head around it, he sat up, and taking one hand, pressed his palm into Arthur's chest. It didn't move. At all. And that couldn't be right. Someone who had just died would be malleable, soft to the touch.

He tried lifting up the chainmail, thinking to see if there was some kind of armour underneath that would keep the body from yielding, but the links resisted any attempt to move them. They, too, were as hard and unbending as if carved from a solid block of stone. As was Arthur's hand and his hair and the cloth of his trousers.

Then it hit him. Arthur wasn't dead.

He was frozen in time.

Not dead, Arthur was not dead.

And Merlin could breathe again.

Realising that, in his torment, he must have instinctively pulled magic to him and pushed it away again, straight into Arthur's body, Merlin couldn't help but be thankful for it. When he was younger, stopping time had been an odd thing, not useful at all except maybe for rescuing his mum's clay pots when he'd knock them over, or playing silly games when he was bored.

But now, he'd given them more time to get to the lake and bargain with the Sidhe.

Arthur was not dead.

Around him, the storm quieted, the fires faded into grey smoke and there was silence.

Not dead.

Taking a deep breath, trying not to sob with pent-up grief, for a moment, he just knelt there, watching Arthur. Captured in an instant, he was alive, alive.

There was no time to waste. Merlin wasn't sure just how long the time-stilled moment would last, and on foot, the lake was hours away.

There was another problem, too, one that was ridiculous and would have made Merlin laugh if it weren't so dire. Laying there on the grass, Arthur was stiff as rock; caught in time, he was unable to bend or flex or relax in Merlin's arms. It would make things infinitely more difficult, but Merlin had come too far and wanted it too much to stop now.

With a great heave, he pulled Arthur up, then began to drag him down the slope toward the lake, one agonized step at a time. He went carefully. He didn't dare try to use magic to help ease his way down, make Arthur float or something. It would have made things so much easier but it might also restart time and Merlin wouldn't risk it. He wasn't willing to bet Arthur's life on something so frivolous.

So he kept going, making sure he didn't stumble or trip, making sure the branches hit him and not Arthur. It was a struggle and mostly he looked down, watching his step. But once, as he glanced back up the hill, he could see a wide band of burnt woods and a patch of bright grass in the middle of it all, a bulls-eye of green surrounded by a swath of destruction.

It was a fitting monument to Merlin's grief.

Then he turned his attention back to saving his king.