This, Jaime thinks as he looks down at the procession marching before him, might be the worst possible time to be reminded of his sister.

The ceremony he's about to participate in had been explained to him in great detail – it's meant to be a union between the old and the new faith, though he might be the only element of the latter here. He's masked, face and hair hidden underneath the regalia of an entity that the priestesses call the Horned God, and he's to kill a stag – spill blood on the hungry spring earth – and then bed their chosen one; the girl playing the role of the Maiden Huntress. She could be anyone – he happens to know just the one priestess around the right age, and he hasn't been allowed to see her since they had been children – and the chances of her being his sister of all people are likely one in a million, but he can't help but entertain the thought as he looks down at them from the cliff he's supposed to start the hunt on as soon as she reaches her destination. Her golden hair falls in waves almost down to her waist, the lower half of it unhidden by her headdress, and her opulent gown is in the colours of their (his, his, there's no them if it isn't her) family's crest. There isn't much else that he can see from all the way here, but as soon as she looks up to face him, he knows.

Jaime takes that as his cue and breaks into a chase as soon as he spots the priestesses's sacred animal somewhere to his left, but his heart is barely in it – it's not blood and death that he's eager for, even though he'll do his duty – no, what he wants is to reach that cave already, look upon the altar there and the Goddess's servant laid for him on it, and – more than anything – he wants to be proven right. The women of the old faith call Beltane's fertility rites the Great Marriage and although it's only – according to his father – more of their wretched symbolism – he knows somehow, deep down, that they had given him the perfect bride. He imagines that only their most exceptional student would be granted the honour of acting as a stand in for their Maiden Huntress and there is no one as exceptional as his sister.

Her name steals across his mind, gentle and hesitant like a caress. She had been taken away from him years ago in service of the goddess, despite their collective ardent protests, but she's haunted his dreams countless of times since then – there is no way she had been a figment of his imagination, considering that they hadn't met each other in adulthood and he would have had no way of knowing what she would look like. It's a sweet torture; knowing what it's like to be close to her, to hold her, to kiss her, knowing all the while that she's locked away in a world beyond the veil of this one; someplace where he can't reach her at all. It's mortifying, too, since he shouldn't be imagining any of it, but if it really is her waiting for him tonight, then perhaps it's simply fate. No one can fault him for it.

He doesn't even consider the idea of letting this – her – go, even after all those years. Their mother had had a true connection to her, but Joanna had been dead by the time his sister had officially been sworn in to serve the Goddess, and when Jaime had felt it, clutching at the searing pain on her forehead where she had been branded, his royal father had seen it as the perfect time to get him to give up the hope of ever seeing her again once and for all.

"Your sister is more magic now than anything else," Tywin Lannister had said, "and what you remember from your early years together is likely long gone. Do you think I would have sent my only daughter away if I had had a choice? You know what flows in the blood of the women in our family."

"Yes, Father," Jaime had said, barely hearing a word of it. His adolescent years had seen him waving goodbye to a good majority of his childhood memories – the ones not concerning his sister, that is – and he'd recalled one unfortunate afternoon, the day before he had been made to move to the other side of the castle and a guard had paced ceaselessly in front of the door to her chambers until it had been time for her to leave with the priestesses. Joanna had seen them playing together – he would have called it a game back then, even if he wouldn't now – and suddenly, the urgency of getting his sister to tame the magic she'd inherited from the female side of the Lannister family line had been made everyone's first priority. Within the fortnight, she had been torn from his arms and sent where he would never be able to follow her.

It could have been a coincidence, of course, but Jaime had been too angered by it back then – and ever since, really – to believe in such trivial things. There are no coincidences where their family is concerned.

All those years – all those visions – and he had done his best to refrain from reaching out again, scared that someone would know, or worse yet – that she would be as horrified by the way every thought of her makes him feel as he knows he himself should be. Now, though, even that final bit of restraint has fallen away – if he had recognised her on first sight, then Jaime is sure that his sister, with magic at her fingertips, had known him as well, and she'd still allowed the ritual to proceed.

For the first time in over a decade, he doesn't wait for her to appear as yet another untouchable vision – instead, he reaches out into the night, barely expecting a response.

Cersei? Cersei, are you there?

And there she is, grasping back at him in the impenetrable darkness around them – his twin, the part of his soul that had been torn away, his beloved bout of chaos in a world put in perfect order. His sister. Cersei.

There are no words he receives in response, but the affirmative is so loud in his mind that the next time he catches sight of that damned deer and takes aim, his spear lands directly in its heart.

~.~

He really rather wishes he could take the mask off. It's an unnecessary weight on his already overheated face and, worse still, it will hide him from his bride. It's not a real marriage, he tries to remind himself, and vanity is a sin on top of that, but he sees no point in honouring tradition when they both already know who the other is.

Still, he dutifully follows the plan set out for him, eager to find his way inside the cave instead of being stopped by the priestesses guarding the entrance for a berating, and his breath freezes in his chest as soon as he discards the spear and the deer and walks into the cavern where the altar should be.

His Maiden Huntress is laid out on the raised surface, surrounded by enough furs to nearly drown in them, staring back intently through the finery. She'd been stripped of her gown at some point, only a thin shift still covering her, other than yet more covers made out of the hide of some unidentified animal. Jaime greedily takes in every part of her that he can see, eyes lingering on the details – her golden mask, covering everything but her lips, the golden paint marking her face, chest and arms, symbols he doesn't understand painted all over her, the way the candles and torches illuminating their supposed marriage bed bathe her bare skin in shades of red and pearly white. It's mesmerising. She's mesmerising.

She rises up to a sitting position, eyeing him warily as he tugs her covers out of the way and discards them on the floor. He'd been ordered not to speak – not to do anything other than what he'd been sent here to do, really – and the temptation to call out to her and hear her voice in response is almost unbearable. Instead, he bites his tongue and braces himself on the jagged rock that serves as an altar, crawling up the Maiden's body so that he can look upon her more easily.

It's her. It has to be; her eyes are the same shade he remembers – leaves in early spring and the sea under sunlight; emeralds when they've just been wrenched from the earth and before they'd been forced into shape. He can see them just fine because she's assessing him the exact same way, taking in the little she's being allowed to see with startled curiosity before her face settles into the self-satisfied smirk he's seen so many times in his not-quite-dreams.

After that, it's only natural that she's the one to break the silence. "I'm not her."

Liar. "Who?" Jaime asks, grateful for the justification to break the rules that he'd just been given. He knows the answer, though then again, they both do, even if she's likely to keep pretending otherwise.

"The woman you're thinking of. There is another one, isn't there?" Even through the headdress, the exaggerated petulance she displays would have made him laugh if it hadn't been quite so frustrating. "A lover, I assume."

Jaime feels his face flush. He'd accepted the idea of her disgust of horror, but he'd never imagined mockery. "You know who she is."

"I don't. How would I know? I am not of your world. Its people are unfamiliar to me."

He slides a hand down her side; grips her by the thigh until he can wrap her leg around his waist and press himself even closer to her – as close as he'll ever get.

"It's a good thing, sister, that they haven't taken away your ability to lie."

"They?" She laughs, but it's a shallow, breathless sound, and heavy with anticipation. She settles into his arms, inviting more of the touch that he's all too willing to give. "Were you afraid that they would turn me into a Fae? They couldn't if they'd tried. I'm as human as they come. Don't name me," she says in a bout of bitter irony, frantic when he opens his mouth and the first letter of it fizzles out in a hiss. "You mustn't say my name, no matter what."

"Why? Would it give me power over you like it does in all those old tales?"

"You'd like that, wouldn't you? It might have, if I was one of the Fae," she stresses again. "There's a not insignificant chance that we're being listened to. If you get just a little louder and someone realises that we know each other – and what we are to each other in the first place – there will be hell to pay." Another one of those sardonic smiles. "Hell. I suppose Father would think us both headed there. His daughter is a heathen and his son is a man who would willingly bed his own sister."

Jaime shivers, though the torches around them keep the cave well beyond comfortably warm. "And you? Are you willing?"

"Would I be here if I wasn't? You don't need to ask. You only need to remember that tonight, I'm not her."

He might have to indulge her, Jaime recognises, unwilling as he is to do so. "Who are you, then?"

"The Maiden Huntress. We both have our roles to play and I have been informed that my participation tonight is crucial to the fate of the world." Her fingers ghost over his bare arm, making him stand as still as the deer he'd been chasing, as if careful not to scare her off. "I would advise you to be careful."

"Always." Pushing the strings of gold holding her mask together out of the way, Jaime traces a finger over the brand on her forehead – a full moon in the middle, surrounded by two halves facing different directions. "Maiden," he repeats absently. The Goddess has three faces, he had heard a long time ago. "Maiden, Mother, Crone. Your keepers out there are the crones, I assume, and you're the maiden. If this night is of such enormous importance and the role of the mother is missing, then perhaps—"

"The Goddess works in mysterious ways," Cersei interrupts him, voice clipped. "I would rather not discuss our practices with you just now."

It only makes sense, at least in his own mind, and it stings that she wouldn't even consider it, but Jaime isn't here to have his feelings respected; he's here to solidify a union.

"If that is what this ends up being about—"

"That's enough, brother."

Her voice is softer than silk, the words whispered in his ear where no one else would be able to hear, and Cersei nudges their coverings just enough out of the way to be able to kiss him, both soothing and decisive. Despite his own stubbornness to pursue the conversation, Jaime groans, tongue running over her lips before it delves into her mouth. It's a glorious sensation – to share his breath, his very soul with her – and he never wants it to end, but it has to, if he's to fulfil his purpose here. He wants to look her in the eye and he can't do that if he's kissing her, so he pulls back and helps rid them both of their minimal clothing before laying her back on the furs, waiting for her affirming nod before letting his hands wander again, one still idly massaging her side while he uses the other to press two fingers against her core where she's wet and heated for him. They don't have all night – he can hear the cracking fires outside, the chants and the prayers meant to help the ritual along and knows that sooner or later, someone would come looking for them. Later. He can do all the exploring he wants, later.

Cersei's eyes fall shut when he first enters her and Jaime holds on tight to her even as her thighs wrap around his waist again, letting him in and urging him on. She feels so intolerably good that he's not sure how long this will last, but that's all right, he reminds himself – it won't be the last time, no matter what everyone else seems to assume about that. Now that he has her with him again, there's no way he's giving her back.

"Oh, Cersei." He shouldn't say it, he shouldn't, but it doesn't seem to matter – her name is magic all on its own, chaining them together, keeping her here, keeping her his. The sentiment seems to be returned, at least, because she clings to him with every part of herself, nails scratching at his arms, her lips leaving haphazard kisses on his throat, her cunt clenching around his cock as if she wants to keep him inside her forever. He would let her; would let her do anything she asks. Jaime braces himself on one elbow to adjust his angle, delighted when her breath leaves her in a gasp, her brows furrowed in silent appreciation, lips falling open even as a stray tear slips out from beneath her closed eyelids.

"Have I hurt you?" He asks, though the idea of letting go of her now would be a monumental effort. Cersei shakes her head, thank God, and looks up at him again, the bliss written over what he can see of her face as sincere as it gets.

"Not at all. You can go faster, I don't mind— oh!" She tightens her arms's grip on him when he complies, her smile widening. She's vocal about the things she enjoys with a sort of freedom their father had been trying to lecture out of him for years and it's contagious; it makes him want to learn everything she already knows about the world surrounding them and give himself over to it just as willingly. "Oh, Jaime, that's good. Yes, Jaime, Jaime—"

It fills him with a vicious sort of satisfaction; knowing that he'd made her feel good enough that she'd refused to heed her own warnings about names and the power they could hold during this ritual. With her urging him on, it doesn't take a long time for his pleasure to build up to its climax and Jaime does what he can to bring her along with him, fingers digging into what appears to be her most sensitive spot, given the sounds it forces out of her.

And sure enough, when Cersei cries out and arches up against him, her walls fluttering madly around his cock, Jaime lets himself sink down on top of her, burying himself to the hilt as he comes and once again – for the first time in more years than he cares to remember – his soul sings.

~.~

Cersei lies in his embrace afterwards, in the silent trepidation that waiting for the priestesses to come and take her away again makes, and as they catch their breath, he answers her questions about life back in Casterly Rock. He tells her about all the things Father had told him about her – most of them wrong, to his devastating lack of surprise – about Tyrion, about all the changes that had occurred in her absence until, finally, pressed by her questions, he tells her about his supposed betrothal as well.

"Nothing is decided yet," he says, desperate to convince both himself and her. She would be no one's mistress, he knows, and the idea of spending the rest of his days with Lysa Tully by his side is far more unbearable than it had been before Cersei had come back into his life. "I only have to wait until I'm king and then I can be with whoever I wish."

"I can't," she says, just as he had feared she would. He can't fault her for the possessive edge to the words when he had done his damnedest to make sure that she's his before she's ever anyone else's, and the idea of her wanting him – loving him – enough to be possessive at all is a far too pleasant one. "If I stay in this side of the veil between worlds, it would have to be for good. You shouldn't let that stop you – I'm sure such a marriage would have quite a few advantages."

"Well, yes," Jaime shrugs, though it's not too convincing when he draws her closer to him once again, pulling her over his body until she's seated on his chest. He wants her in any way he can have her, and they haven't as much as scratched the surface of all the possible options. "An alliance with her family will guarantee us support from the Riverlands and they're a pathway to the North. If Father ever does plan to unite our kingdom with the ones surrounding us, this would be the most peaceful way." He rubs his palms along the smooth skin of her thighs, the golden marks smudging and leaving sparkling trails on his fingertips. Perhaps she is one of the Good Folk, after all; leaving faerie dust all over him. "But she isn't you."

"She couldn't be, could she? It's all right; I've only claimed you as much as you have claimed me." Cersei leans down, the waves of her hair a curtain shielding him from the world, her breasts far too temptingly close for his touch to not stray upwards and tease at their peaks. Her breathing hitches, her hands curling into fists, and he increases the pressure, almost cruel with it. "I'm sure it'll be no trouble at all, if she's as beautiful as me."

"You know she's not," Jaime snaps, all too aware of the position they're in; of how easy it would be to tug her up just that final bit upward and get to put his mouth on her. She doesn't budge when he pushes her to do just that. "Father was right," he adds, bitter resentment occupying what should have been a sweet, if temporary, farewell. No matter who he ends up marrying, it'll be her that he remembers every time; this night that he'll remember after every sundown. "Magic never does anyone any good. You're a wicked creature."

"As wicked as any woman in our family, blood of my blood." The last is said in a tongue ancient enough that the earth must barely remember it, but Jaime knows the expression by heart, and it brings another shudder out of him. "Shouldn't that make the choice easier still?"

"Do I have a choice?"

"Of course you do." She sounds awfully serious for a moment, one hand caressing his face, unbearably gentle. "Never forget that." Finally, his sister relents when he pushes her again, and Jaime groans at the first taste of her when she straddles his face and his tongue swipes at her folds, causing her to whimper and clutch at his shoulder, her other hand propped on the wall of stone over his head. Still, she finds it in herself to speak. "So, what will it be? Is it the North you want? Or is it me?"

He doesn't have to answer at all, damn them both to hell, he thinks as he relishes in the essence of her, smiling deliriously when Cersei's composure slips away in favour of yet another moan, her hips pushing back against his mouth until she's riding him with all the dexterity of someone ten times as experienced and he's lost in her; lost for good.

It had never been a choice at all.