The Challenge Of Our Rival

Arthur isn't sure what he's expecting, but it's not what he finds.

When he enters the large cavern after traipsing through passages and tunnels for a short while, it's to see Merlin stood up against one wall whilst the serving girl that had taken him away is peering into what appears to be a bowl full of water. Merlin notices him, of course – he always does – and he smiles, but it's a crooked smile because he's clearly in pain, and Arthur feels a flush of hot anger.

The girl looks up just as Arthur begins to descend towards Merlin, and he's being as quiet as possible but clearly is wasn't quiet enough, and whilst she looks momentarily shocked, she recovers quickly.

"You're the last person I expected to see here," she remarks, but Arthur isn't listening. He's staring at Merlin, who's staring back.

"You came," the warlock whispers, and even from across the cavern Arthur can hear him and his heart breaks a little. He makes to go to him, but the girl acts first.

"I never said that you could speak, Emrys," she says coldly, and Merlin says nothing else. She has spelled him silent. Arthur hears a deep, animalistic growl and realises just a little too late that it came from him as he glares at her, but nothing more. She is powerful – he is not. He will be killed if he attempts anything, he knows this, and then he will be of no use to Merlin at all.

Then as she stares right back at him her face shifts, but not completely – it just becomes some sort of strange amalgamation that isn't quite one and isn't quite another, and when he concentrates too hard he can't see it at all. But it's enough. He knows who it is.

"You're the one that poisoned him," he snarls, and she nods, her face full of satisfaction.

"I have many names," she acknowledges, and tilts her head to one side. "But your father knows me as Nimueh."

She raises a hand suddenly and he finds himself flung against the cold damp wall, rocks digging into his back and one has drawn blood. He tries to move but can't – she has him frozen, the same as Merlin.

"Let him go," Arthur orders, though he knows that he's in no position to be making demands, and she simply quirks an eyebrows at him. He feels his heart sink, and knows that this will not end well.

"I have a score to settle with Merlin. I may as well do it now, whilst I have you here watching, Unable to look away," she says with a startling finality, and though he strains against the invisible bonds, he cannot break them. He may look desperate but he doesn't care, because he is.

"Please don't hurt him," he begs, and she looks at him with what could be wonderment. "Do whatever you want to me but please, please don't hurt him."

She pauses before replying, her face carefully composed, her hand still outstretched towards Merlin.

"If only your father knew that you were capable of such love," she replies quietly, then her face contorts and she turns to the warlock as she screams out a spell.

Arthur doesn't move, though he's screaming in his head, but then he can't because Nimueh has him pinned to the wall. There are sparks fizzling over Merlin's skin and his face is screwed up in pain, and Arthur wants nothing more than to pull his advisor into his arms and strike down the sorceress but he can't, he can't save Merlin.

Something deep within him that's been growing slowly without him noticing explodes in a burst of gold and red.

It's a ring of burning light than robs him of his breath, and his eyes roll up but he forces himself to watch as it crashes through the cave, knocking Nimueh off her feet and releasing Merlin from her hold. His advisor drops like a stone, and Arthur realises that he can move again – he's on his knees at Merlin's side before the magic has begun to fade, still bright and powerful in the room with them.

He feels Nimueh fire a spell at his back but it doesn't affect him, just bounces off, but he's not concerned with that because Merlin's breathing is shallow and there are faint scars littering his face that shouldn't be there. Then his eyes open, shining gold, and Arthur releases a breath that he didn't know he'd been holding, and something within him snaps.

He's whirling up to his feet, a spell forming in on his tongue and hand outstretched even as he feels Merlin's gentle touch on his knee, even as he knows that this shouldn't even be possible, but as his own spell hurtles through the air it's met by Nimueh's own and they form a shimmering barrier, both equally strong, a shield between them. Arthur's glaring at her, but she's smiling at him. A cold smile.

"I had wondered when this day would come, Arthur Pendragon," she says, sounding amused. Arthur starts forward, fully determined to charge her on principle, magic be damned, but he feels Merlin's hand on his shoulder and turns to him.

The warlock's face is drawn and pained, and he's wincing and holding his stomach with his free hand, but his eyes are clear and full of something that Arthur can't decipher. But he wraps an arm around his waist to support him anyway as he turns back to Nimueh, forcing himself to stay calm.

"Explain yourself," he says shortly, not daring to say anything more, and feels Merlin shaking against his side.

"Your innate magic, of course," she replies derisively, stepping down to stand just on the other side of the barrier, just out of reach. "I had wondered when it would manifest."

"This is a result of Merlin's transfer of magic to me, nothing more, though we had believed it gone," he points out, already getting angry and annoyed and he just wants to get Merlin home. Then he feels a flood of love and gratitude, and he knows exactly where it's coming from.

"Oh no, little Prince," she hisses, her face shifting once more, and he frowns. "Your father never told you the truth about your birth, did he? About how your mother died?"

"My mother died in childbirth," he barks, holding Merlin more securely, and she throws her head back and laughs loudly.

"That's true, I suppose. But the truth of your birth is that you were created from magic, Arthur Pendragon – you were created in a place where no child could be conceived and in giving you life, Igraine lost hers."

"Don't you dare spread such lies about her!" he spits, and there's a spell forming again but it's stopped by Merlin's calming hand on his chest.

"It's true, Arthur," he says in a strained voice, almost as though he'd rather not admit it, and honestly how would he know? The Prince feels his own face drawing in as he stares down at his advisor, and his voice is low.

"How do you know this?"

"Gaius told me, a while ago. He said that he couldn't take the secret to the grave. All Nimueh did was confirm it."

And Merlin looks so miserable and hurt and apologetic and there are ripples of despair there too, and Arthur could never be angry with him anyway. So instead he looks up to Nimueh, and his eyes may be glowing, but they don't feel golden like Merlin's do.

"You're going to regret ever taking Merlin from me," he says quietly, but there must be something in his voice that's dangerous because her confidence falters a little and so does her side of the barrier, the magic shimmering and edging just that little bit closer to her.

"Don't be so stupid," she growls, but her tone is belied by the fear in her eyes. "You don't have half the power that I do."

"You're right," he replies, quite simply, advancing towards her. "But I'm drawing on Merlin's power now, and he's twice as powerful as you."

And with that, Nimueh seems to realise that she will die if she stays any longer and with the same whirl and flash of light she disappears, taking her magic with her, and Arthur's own original spell rushes to hit the opposite wall with a rumble. There is silence.

Then Merlin crumples, all his remaining energy gone, and he would fall to the floor if it weren't for Arthur's arms already around him, easing him down gently. If he's been bleeding, he's stopped, but there are still tiny scars all over him that Arthur doesn't recognise and he's pale and shivering and drained.

Arthur feels something clench around in his chest and he gathers the other man up in his arms, shifting him so that if he wakes he'll be more comfortable, and looks around the room. He has no idea what she had been doing to him before he turned up. He possibly never will.

He looks down at Merlin, at his beaten body, at his own glowing hands curled around the young man, and closes his eyes as a tear threatens to escape. It doesn't manage it.

Arthur tightens his grip on his warlock and begins the trek back to Morgana.

Don't lose your grip on the dreams of the past
You must fight just to keep them alive