From a Tumblr prompt:

So, what if you did a combined Sansa/Tywin - Catelyn/Tywin fic - lemme explain: modern AU, Tywin had a secret relationship/affair/whatever with Cat when she was younger (think late teens/early 20's, pre-Ned), then some decades later, ends up having an affair with Sansa ... c'mon, you know you wanna ...

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The banquet was just like any other - a pretentious feeding ground for bribes and favors. The only notable exception being the pious Stark patriarch dangling his daughter on his arm instead of his wife.

Although, at first glance, even those milling around and related by blood mistook the girl for the woman. It was hardly fair to do otherwise; the daughter - Sansa - was every outward bit of her mother at the same age it was hardly a stretch to confuse the two.

And from a man with intimate knowledge regarding one half of that equation, the observation denoted compliment in either direction.

Either direction.

Letting that innuendo slip into place, Tywin's cock strained at the conjured image of Catelyn overlapping the reality of her daughter standing little more than three meters away. His entire reaction threatened to become a PR nightmare when his mind wandered a little more into recollecting Catelyn at that age - flushed a pretty tint of pink from her breasts to her cheeks, more often than not happily relieving him of such problematic discomfort.

She had been a gift, Catelyn; equally wild as she was subdued. Their… encounters… were kept locked behind doors of unyielding discretion. However, what happened beyond those doors… The kind of inspired debauchery she encouraged…

Tywin bit down as he fought to regain control.

His mind was having none of it.

Their experiences together were peerless. Countless professionals retained throughout the years could never come close to recreating them.

And how he tried.

Catelyn Tully.

Tywin huffed a breath or two and tactfully watched Sansa effortlessly charm every worthless bootlick her father felt needed introduction. She came by that lure honestly, as natural an ability as her mother ever had.

The last time he saw her mother, Catelyn was trembling, not in fascination or seduction, but a vicious churn of anger and sorrow. It couldn't be helped, they had been getting too close, too complacent, and he'd let slip one too many advantages.

More to the point, he felt when he didn't want to, he cared when it was an inconvenience, and it was much better to destroy that kind of joy early then to let it fester and become weakness. Catelyn was simply collateral damage and, at the time, an acceptable loss.

To this day Tywin felt no remorse for hurting Catelyn Tully in a bid to save himself potential embarrassment. What he could not foresee, however, was her refusal in sustaining their arrangement.

He had met her in the small house purchased for their purposes, and merely made it clear the new parameters of their relationship. He'd conceded in allowing her greater freedom to continue as they had been, she could even marry if she wanted - just not him, not ever.

That same night Catelyn left the unassuming house in the unassuming neighborhood, perched squarely on the border between the Westerlands and the Riverlands, for good.

Without bothering to pack the things he'd bought her, she simply piled the great many clothes and baubles into the hearth and lit it. Subsequently burning down their unassuming escape in a spectacular display. A rather fitting end, he'd thought, seeing as she never spoke to him again. He had attempted to contact her soon after and learned Catelyn had run north.

It all seemed final after that.

The girl had been fiery, to be sure. Could hold a grudge better than he, without any doubt. But she had been so young. Catelyn came to him with a virginal calm and left his bed a tempest. She was his finest work, and if regrets were to be admitted, that twenty years ago he couldn't muster the interest to keep her in his bed would steal that claim.

Tywin clenched his jaw in the present, watching the man into whose arms - and bed and life - he'd chased the last woman who'd ever pleased him, as that man led around a carbon copy of his tempest.

Something ugly welled inside him then. With his cock no longer an issue, he could concentrate on the ill fit coat of jealousy on him, pulled taut like snake about to shed its skin.

Much like that same beast, at that same pinnacle, Tywin now looked upon the world through clouded eyes. So when it was his turn to present himself to the shockingly lovely girl, ignoring the painfully boring father, he could hardly fathom saying no when she casually asked for an audience.

Once the ostentatious dinner had been served and cleared, a head full of elegantly styled auburn waded into a sea of grey, and emerged again on a shore of gold, wearing something like a grin - a tiny bit lopsided, brimming in youthful bravado.

I've heard stories about you, she'd said, tugging his sleeve, and his person, farther into the shadows along the edges of the ballroom.

Is it true you were close to my mother? she'd asked, a brush of fingertips guiding his face until his ear met her lips, so she could be heard over the noise of chatter and music.

Do you have a room here? she'd propositioned, her eyes dancing in the exact same way those exact same eyes used to, before, when therein laid a promise of something deviant waiting only for an answer.

He didn't have one, a room that is, but that was a problem easily fixed when she flashed a key-card to her own.

::::::::::::::::::::::::::::::::::

Hunched over the daughter, burying himself in a tight sleeve of heat he could only recall if he cleared his mind and concentrated, it was the mother's voice he heard. Warm gusts of history swirled salty and sweet from her mouth, tasting of everything he had spent twenty years trying to recapture.

Tywin, she gasped.

That was it, that was the shove he needed to step over the threshold. This was his chance, he commented to himself. Sansa was new means to past rapture.

And then, Sweetman.

Her delicate purr whispered an endearment known only to one other person, and Tywin fucked for all his worth, for every penny of that fortune, to have this girl say it again.

She did, over and over.

He unraveled at the same pace.

When he came it was with a shuddering thrust and roar drawn long and low, and maybe in the shape of a name - he neither knew for sure, nor cared. What was truth, what he did know was that he sprawled spent and tangled, limb for limb with the woman beneath him - just as he always had with the other woman, before.

Sansa kept him inside, cradled him to her bosom, and muttered words in such a way he was sure it was a song. It was all consistent with the former, he had lived this very same comfort every time he bedded…

No. The past was done. This was now. She was now.

The daughter.

Sansa. His brain looped the name, first to revive any dregs of pleasure still scurrying in his blood, then, second, to firmly secure it where he had once said Catelyn.

Unwinding his body from the vine of hers, he turned and pulled her close, curved her back to fit his front, just like… just like… And dozed with the smell of long forgotten shampoo corrupting his dreams.

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It was the dip of the mattress that woke him, not the fact that Sansa had peeled out of his embrace.

No matter. Even in the middle of the night, even through the groggy haze at the start of wakefulness, he could see a soft grin on her lips. He scrunched his eyes in return, leaving the girl to interpret the gesture as she pleased.

This was right for him. He sighed and turned over onto his back letting the cool air at his still damp cock.

She was perfect in her youth, guileless and invincible, and the mere act of taking him into her bed showed a streak of fierce independence - a rebellious element that could be used against her family. Tywin could influence this one in the way he failed to do with her mother. He'd learned from his error with Catelyn, he would do better by Sansa. To better serve himself.

His head turned to the side and he watched, pleased and sated, as the girl rose from the bed, her pale complexion softly blurred along the edges, illuminated just so by the moonlight.

Beautiful, he thought.

And then, Mine.

"I desire you, Sansa. Very much. You will want for nothing if you stay with me."

She smiled a little, a lot like… And placed a knee on the bed so she could lean over him proper. The kiss she graced him with was so easy and so familiar, he whimpered shamelessly for the need of it; holding her close, reaffirming that she fit this way as well, moaning when the lace of her bra scraped across his chest and over one of his nipples.

Surging up to kiss her harder, deeper, Tywin let the slide and suck of his mouth and tongue tell her plainly that he would fuck her again. That this was nothing in comparison to what they could build together.

Hot palms pressed against his chest as Sansa pulled back, stepping from the bed. She smiled again, that darling thing, as she reached toward nightstand then passed him a tall glass of water. Aftercare that seemed intuitive, as though she knew he would surely ask.

He always did.

Gulping greedily, Tywin planned in his head as she continued to dress, pleased that she never once took her eyes from him.

"Would you like that?" She asked.

The question came innocently as she slithered into the hugging black dress he'd removed from her hours prior. Tywin had to blink out of the filthy fog of watching her body stretch long, tightening in all the right places, to don the garment, then took another few moments to realize she had inquired as to his offer.

Returning the glass to the nightstand, Tywin remarked, very truthfully, "Yes."

Why not honesty? Establish her trust in him by using earnest answers to simple questions, then move forward from there.

Sansa was slipping into her shoes, still smiling softly, still holding his gaze hostage. As she moved to the door centered on the far wall of the room, Tywin spoke again, this time with a tone that was unmovable.

"Tell your mother and your father you have a job in the West. I will arrange your travel a week from today."

The pretty girl's silhouette stood static in the partially lit room. The only part of her that moved at all was her mouth, and it wasn't to form words of agreement. Her lips flattened to a grim line at the same time her head turned slowly from side to side.

Ice crept through his veins then, to every corner of his body. Muscles bunched and shivered in response to the prickling pain.

"No," she said. Her voice as wintry as he felt.

The fevered skin he grew earlier in the evening sloughed away, papery and useless against the weight of his own folly. Amidst the cold score to his ego and the hot scorch of his ire, clouded scales shed from his eyes to further clear his vision.

Why would she dress to leave her own room?

Why would she leave through an adjoining door?

As though Sansa read his mind, a quick twist of her wrist opened the passage; his blood sparked electric with a jolt of adrenaline, barely overshadowed by a masochistic sense of joy in knowing what - who - he was about to see.

But that fire snuffed and turned to lead when instead of her it was grey hair and overly solemn Tully eyes that greeted him.

The Blackfish. Now, there was a dangerous man. Where Tywin Lannister bought and sold lives, it was this man who acted as fate; who meted the whim of those who could afford the service.

Brynden Tully turned softened eyes to Sansa. "Did he hurt you?"

The cunt had the nerve to laugh.

Why was he so riveted to this exchange and not fighting to escape it?

The Blackfish leaned in, catching the girl's ear, his words now private due to their proximity. Tywin breathed heavily as she smiled in the best of humour, his lungs burned with a fury his body could not coordinate. Her eyes widened slightly at whatever her great-uncle spewed, and this time she angled her head toward the bed and laughed directly at him.

"Oh, yes," she said, puffed out in a forced kind of chuckle, scanning the lion from eyes to cock and back again. "Pathetically so."

Sansa stepped past her great-uncle into the room beyond, leaving the two men staring. Brynden moved first, sitting in a chair conveniently facing the bed.

"What? You're going to kill me?" Whatever haughty incredulity Tywin aimed for was cut off by a wheeze of air pushed from his cinching chest. The pain in his limbs intensified.

"No." Tully said conversationally. "Sansa's already done that." Seeming to find a comfortable position in the chair he chose, Brynden crossed his legs, settled his hands in his lap, and smiled just like every other Tully: deceptively. "I'm here for the simple enjoyment of watching you die."

If there was any kind of clarity in death, it was this: The maw of obsession can only truly be glutted by a singular object, never a replica. Whereas the spear of revenge can be honed and hurled by anyone.

Tywin kept swallowing, his throat felt like cement. He could hear himself panting as the nerves allowing him any kind of posture died systematically - and, of course, paralysis would point him toward the enemy.

The world dimmed at the edges, his breathing slowed and now sounded sickeningly wet.

And there, for a moment, he was sure he saw the ghost of Catelyn Tully emerge from the shadows.

She wasn't dead though. Catelyn wasn't dead. He was thinking of the wrong woman from his past. Blinking was becoming a chore, and it took too long for his brain to finally catch up to what he was seeing.

The ghost with her hand on Tully's shoulder was Sansa.

The Blackfish patted that hand, and Tywin knew envy as his final emotion.

"Are you sure you want to see this to the end?"

I do, whispered Tywin's mind. However, his body refused the command. The world was black and gone, save an echo of a voice he could no longer recognize.

"Yes," it said. "I promised her I would."