It's been awhile since I wrote anything, but having been completely sucked in by A Song of Ice and Fire I had to give it a go.

As always with fan-fiction, none of this belongs to me.

Warning: Spoilers and mentions of incest – it is the Lannister twins, after all.

He found his sister sitting, of all places, on the Iron Throne. He paused in the doorway and observed her for a second. Her blonde hair had only just began to grow back and its shortness only increased the similarity of her appearance to his – if she hadn't been wearing a gown, and if he'd still had two hands, it would have been difficult to tell them apart.

She was muttering to herself. Jaime was reminded forcefully of the Mad King he had slain in this very room. Though if rumours were to be believed, she was slowly going down the same path. The Mad Queen, he'd heard the smallfolk calling her on his journey down from the riverlands. That's what trying desperately to rule a kingdom you no longer have control over did to you, and she had been trying to rule it single-handed. Anyone with a lick of sense had long abandoned the Lannister cause.

"A young queen more beautiful," he heard her mutter.

A young queen, he had no doubt in his mind what that meant. Daenarys Targaryen and her dragons were only a short distance away from the city. People, highborn and smallfolk alike, had declared it a miracle the day she appeared at Griffin's Roost on the back of a black dragon – half-starved to death though she had been. The news had spread like wildfire and it hadn't been long till her army across the narrow sea had heard of her re-appearance and followed her, proof of the unprecedented degree of loyalty that she had earned from the former slaves of Slaver's Bay. She was marching alongside her back-from-the-dead nephew, Aegon VI.

It seems no one stays dead any more.

He pushed the ruined face of the thing that had once been Catelyn Stark from his thoughts. But that was partly why he was here. Brienne. Lady Stoneheart and the Brotherhood had Brienne. To save her he had been told he had to do what was best for the Seven Kingdoms. A test of his honour they'd called it – if he succeeded then, and only then, would they believe Brienne and him had been telling the truth about keeping their vow to Lady Catelyn, and that would save her from the noose.

"The Valonqar." Cersei's mutterings continued.

"Little brother," he said as he walked into the room, recognizing the Valyrian. Cersei's head spun round.

"Jaime," she whispered, her voice caressed his name in a way she usually reserved for the bedroom. "You came." As she stood up, he saw the blood running down her legs – she had caught herself on one of the swords.

"Leave us," Jaime ordered the two Kingsguard who stood guard over her. They looked uncertainly at the Queen Regent.

"Go," she said harshly. "Useless bastards," she muttered before they had even left the room – there was no doubt they had heard her.

"He wants to kill me," she said the second the door had closed.

"Tyrion?" he questioned, keeping his voice calm. Rumours had placed his brother at the dragon queen's side. Jaime couldn't help but remember the last time he'd seen his brother. "He quite possibly wants to kill us both." He saw the shock wash across her face.

"Why?" she demanded. "You always got along with the little Imp. But I always knew, always knew he'd be our downfall. He killed Joffrey. He killed Myrcella. He killed Tommen." Her words were becoming more and more feverish and hysterical as she spoke.

"Myrcella was killed by an over-zealous Dornish Targaryen supporter," he corrected her evenly, skipping over Joffrey. "How someone got inside the Red Keep to kill Tommen is a mystery. For a supposedly safe place, people do keep dying here. Particularly Lannisters recently, and old Aerys, of course."

"And who suggested she be sent to Dorne?" Cersei shot back, her voice harsh and her eyes flashing with anger. "And who managed to escape the dungeons and get inside the Hand's tower to kill our father?"

Maybe the smallfolk have the right of it, Jaime thought as he listened to his sister's paranoid rant.

"Our father deserved his death," Jaime said coldly. "But I'm not here to discuss Tyrion." He would worry about his little brother later, once the task at hand was done. Now was about Cersei.

"The Valonqar will kill me," she told him. Her fury had melted to be replaced with fear, taking him by surprise. Cersei had never been one to show weakness. He watched her for a few seconds more and then he closed the distance between them and pulled her into his arms. It felt natural to hold her again after so long. Her body still fitted perfectly next to his. Two peas in a pod. Two halves of a whole. That was what they were and always had been.

"I can't die while you live," she told him. "Born together. Die together."

Despite it all, he wanted to keep hold of her. To still be stood like this when the Targaryens came to kill them.

No, you can't. Just get it over with, he told himself.

The dagger hidden in his left sleeve slid into his hand.

She was right. Their lives had always been tied together - how fitting that this would be the ending. One of them couldn't die without the other being there.

"I was born two minutes later," he reminded her. The dagger ripped easily through her dress and smallclothes and into her back. Her gasp sounded more surprised then pained. He felt her body press against his as it had a million times before. She would die in his arms. How terribly poetic. A story for the singers.

The dagger fell from his hand and clattered to the floor as his arms went slack. She dropped to her knees like a rag doll.

"Little brother," she laughed and then she continued to laugh. She truly did sound mad now. The blood was slowly spreading around her. He had meant to get her heart and make it quick, but his useless left hand had given her a slow and painful death instead.

Her hand suddenly grabbed out and grasped the stump of his right arm, pulling him down onto his knees next to her with surprising force for a dying woman. He felt her blood soaking into his knees. She placed the stump at her throat and then her laughter began again, louder.

"You can't strangle me," she informed him. Her voice was becoming weaker. Her laughter finally stopped as she fell backwards. For a few seconds he thought she had gone, but her eyes were still open and staring at him defiantly, and he realized he could still hear her laboured breaths. Though the laughing had stopped, a strangle smile still played at her lips.

Jaime leaned down and placed one final kiss on those lips.

"Goodbye, sweet sister," he whispered. His good hand caressed her face tenderly and then moved down to her throat. He grasped as hard as was possible with one hand. He didn't know if it was because of the wound in her back or his hand at her throat, but the light slowly died from her eyes.

He took his hand from her throat and closed her eyes, brushing a kiss against both.

For the good of the Seven Kingdoms. That's what the damned Brotherhood had told him. The more he saw and heard, the more he realized they were right. Cersei would never bend the knee to the dragons – as every other sensible lord had.

That's twice I've saved the people of King's Landing from burning to death, but I'll never hear a thank you from any of them.

He stood up and give her one last look. His sister, his twin, his lover, the mother of his children. His undoing. Their love had brought war down on all of Westeros. He thought of all the things he could have been if he hadn't loved her. But he had, and here he was – Kingslayer, Queenslayer, kinslayer. The accursed of all men.

He walked away from his sister's body and took the seat she had previously occupied on the Iron Throne, just as he had all those years ago after killing Aerys. This time he knew who would be coming to claim the kingdom. It would not be the judgemental eyes of Eddard Stark that found him, but those of Aegon and Daenerys Targaryen. There was no doubt in his mind that Cersei would be right, he would follow her into death shortly just as he had followed her into life.

But the Brotherhood would release Brienne – and they'd be at least one person in Westeros who knew Jaime Lannister did have some honour.

Just a personal pet theory of mine, that 'Valonqar' could technically mean Jaime, as he was born after her. The rest (Daenarys, etc.) I highly doubt is what will happen, I just needed some background. I'm sure GRRM has plans none of us will ever come close to. I'd love to hear your opinions :)