Disclaimer: I do not own Bleach or any of the characters thereof, but I do claim the creative liberties to this story.
He had heard that when someone you love or care deeply for dies, they can be seen in the faces of strangers. The concept made far too much sense to Byakuya, but for him he could only notice similarities. A laugh, a phrase, a gesture, a scent; so many similarities cry out their mockery, their hands reaching out to further suffocate him in the waters of sorrow.
So many years have passed since her death, and he could almost breathe again. He could almost bare to lay alone on a bed void of her comfort and warmth. His body just barely racked with guilt as he was almost able to recall the feel of her skin at his fingertips. And he could almost stomach the way he touched himself as he remembered how she used to move against his body.
Almost.
On nights when sleep refused to claim him, and his seed had long since dried on his belly, his mind wondered to those similarities.
He could remember when he and Hisana had become engaged, how the entirety of his family was against the very notion, everyone except his grandfather, who after only a little fuss accepted it outright. It was after their engagement dinner, when he had introduced her to his family and announced the forthcoming marriage only for the dinner to end disastrously and with no little amount of shouting, that he had went to his grandfather seeking reassurance.
He had always looked to Ginrei for console and guidance, and he was grateful for his grandfather's understanding. After all, the same man who had reared him since childhood had plucked his own bride from less than noble stock. His grandfather's first wife, an arranged marriage of noble blood, ended tragically when she died giving birth his Byakuya's father; his second wife had been one of his servants. So while his first marriage was that bound by duty, his second was spent happily wrapped in love's embrace; the same love that he had once shared with Hisana.
However, when Ginrei's second wife died, he could never find it within himself to remarry again, and it was only with a sad sort of comfort that Byakuya looked back on this. A simple fact that he was not the only one to have suffered in this grief, and such a cheerless similarity made him wonder if anyone in the Kuchiki clan could ever hope to hold onto love.
Then, years later, just after he was promoted to captain, he was introduced to Rukia. Oh how much she resembled his fallen angel, it was all he could do to keep his breath steady and voice calm as he proposed her adoption into the Kuchiki family. His attendants that had accompanied him had been shocked to say the least, but he would have been damned if he had forsaken his love's dying wish nor was he about to discard one of the few precious fragments that remained her.
Yet there was no doubt in his mind, that Rukia would be his greatest downfall…and his greatest folly. Though he would not for one moment regret welcoming her into the Kuchiki clan, but for his sake (and the honor of his late wife's memory) he could not allow himself to express the brotherly compassion that he did truly feel for her. Instead, he had wrapped himself in his emotionless façade and made himself aloof when she was near. If fate had been kind, she would not have looked so much like her sister, then again, if fate had been kind Hisana never would have had to abandon Rukia and he would have never mourned for her, and the semblance really was remarkable.
This poignant similitude was not the only thing they shared. Rukia's voice could almost pass as an enchantingly eerie echo of Hisana's, and their personas as well seemed to be much the same; no doubt fashioned from their meager lives etched out in Rukongai. These qualities had endeared her to him; just the same it had done for Hisana…and, it was these qualities that haunted him as well.
A promise fulfilled, and he really had not received an ounce of closure over Hisana's death. If anything, he only felt the weight on his chest and shoulders grow. So it was, after Rukia had been formally adopted and brought to live at the family manor that Byakuya began to isolate himself even more from those around him. He found himself constantly drawn to his late wife's shrine, more determined than ever to cling to her memory, and often dwelling there till the wee hours of the morning.
Now Byakuya was not stupid, nor was he so beside himself with grief that he couldn't tell the difference between Hisana and her sister. As strong as the similarities were, there were also plenty of differences to keep him grounded in a pained reality. But as he sat in front of her picture, he couldn't help the loneliness he felt creep up his spine, making him delirious in his already sleep deprived mind.
One night, after the servants had long since retired for the day, it was in this clouded haze his mind had cast over him that he barely even noticed a slight weight settle next to him.
His hands, resting on his thighs, clenched in to fists involuntary as the person beside him began to speak. Her soft voice weakly attempting to lift the fog he had shrouded himself in. Eyeing her out of the corner of his bloodshot eyes, he felt the familiar tightening of his chest. Slightly jumping as her small hand timidly grasped his arm, his mind was at war with him. He knew this was not Hisana, he knew it, but his dreary eyes blurred just enough…and Rukia really should not have come here.
He shut his eyes tightly, and lightly shook his head. Yet as he tried to breathe deeply, the scent of aromatic shampoo filled his nostrils, a scent he had all but forgotten. If any part of his mind had been clear enough for him to think properly, he mostly likely would laughed inwardly just at the seemingly determined way fate seemed to enjoy forcing this torture on him.
He felt Rukia move to kneel in front of him, her small warm hand moving to cup his cheek. It took everything for Byakuya to keep from nuzzling into her palm as he slowly opened half lidded eyes to view her face etched with worry. He could see her lips move again, and it was sometime before his fogged mind finally interpreted their meaning.
"Byakuya, my brother, are you alright?"
He clenched his eyes shut tight again and shook his head once more. He could feel himself spiraling, and as he inhaled in once more of the shampoo Hisana once favored, he knew he was too far gone to stop himself.
His arms quickly shot out to wrap around her frame and brought into his lap. Rukia was too stunned to move and could only let out a surprised squeak as she was settled into his embrace. His nose was buried into her hair, too ensnared in his mind's illusion to relinquish his hold. His hand began to caress her side as he let out a shake breathe, whispering his beloved's name into her sister's shoulder. It wasn't until he had captured her lips with his that she began to writhe in his lap.
Rukia's body began to shake as her stunned mind finally kicked into gear. Her small hands coming up to his chest, attempting to push him away, but his strong arms held her fast. She turned her face from his breaking the contact as she choked out softly, "Byakuya stop this please."
"Why did you leave me, my love?" Byakuya kissed down her jaw, stopping to nuzzle her cheek and resumed to make his slow progress down her neck.
Rukia had been told by a number of the servants and her new found family members how much she resembled his deceased wife and had been told that was the reason he had adopted her. So as she sat in his lap, his mouth delicately working on her throat, she had to admit that she had had an inclining that this was why he wanted her there, but there was a limit as to how far she would go just so he could 'reclaim' his lost love. When she felt his hand begin to caress her thigh, her mind was set and began to push harder at his chest. "Byakuya stop this now. I am not Hisana."
His arms tightened drastically and he went to recapture her lips again, but wincing as he felt her teeth bite down harshly on his lower lip. The pain filtered through the haze and shattered the precious illusion he had been all to consumed in.
Rukia felt him tense and his back straighten slightly as his eyes finally shone with much needed clarity, as well as shame and the lingering remnants of lust. His arms slackened and she quickly wretched herself from his grasp and hastily fled to her own rooms, leaving Byakuya to wallow in his shame.
It had been a long time before he could face her after that. In fact, it wasn't until she was doomed to be executed and that orange haired ryoka had literally broken though every barrier to save her. A task he should have been strong enough take on as well, but he was still ashamed of his actions and instead of doing what he knew was right, he shrouded himself in his family's honor and their laws and regulations and his own personal vows.
Then as he lay bleeding in the dirt, his honor shattered, he had called his sister to his side. And for the first time was able to tell her the truth, the real reason for her adoption. His pride had been so easy to choke down that day as he begged her forgiveness for his actions.
He had heard that when someone you love or care deeply for dies, they can be seen in the faces of strangers. Oh, yes, Byakuya had firsthand experience with this concept and he had barely made it through without tarnishing Hisana's and Rukia's honor or shaming himself in the process, but as he broke a vow made to his wife to preserve her secret siblinghood from Rukia, he made a new one to truly embrace her as his own and swore to protect her.
It had been so long since he had been able to just breathe with ease; his shoulders had been so burdened with grief and shame for so long he had forgotten. Byakuya is far from carefree, but on a day of much treachery, he was able to find something he had long since given up hope of finding. Peace and closure.