Now, this isn't a proper songfic. It's more like background music or a soundtrack. Sour Times by Portishead is the inspiration...kinda.
Sour Times
What was he going to do with her?
It had been over a month, and he had meant to dispatch her quickly. Okay, maybe not quickly, but definitely painfully. He had stolen his brother's favorite pet as penance for their last encounter in the desert, the one that had left him with five scars marring his beautiful body. The entire time, she had had such tremendous faith in his brother, such tremendous faith that he would come and save her.
It gave him a plan...and a devious one at that.
He thought long and hard about how to make the little spider pay for her misplaced faith. He wanted to use her affection towards his brother against her in the most painful of ways. He decided he was going to do many a horrible thing to her, but instead of just doing them, he was going to take the added step of convincing her that he was Vash instead of himself. With his powers, it would be no trouble at all, and the result would be so deliciously deviant.
That was the plan anyway.
On the day he had decided he'd finally let her live long enough, he approached her cell and prepared his mind. He unlocked the door and expected the same violent, resistant, insolent creature that he'd kidnapped to be before him. What he saw threw him for a loop: the passion, the lust, the need in her eyes. It caught him off guard just long enough for her to derail the plan, something that never, ever happened. Before he knew it, she had her body pressed against him and she was standing on her toes to kiss him forcefully and passionately.
Instead of killing her, they ended up having sex all day.
He didn't get it. When she thought he was himself, he got the same callous, all business attitude, but once she thought he was Vash, well, he didn't even want to think about what she was like, lest he get weak in the knees again and need to be reminded personally.
He wondered if his stupid brother knew the way his pet felt.
This had been going on for a little over two weeks, and it was two of the most cardiovascularly intensive weeks of Knives' recent memory. His resolve was slipping. Every moment with her, as a different person...well, you can see how that would affect someone. It pleased him that she was doing these things to his body, but it disgusted him to know she thought it was his brother while she was doing it. Was it...jealousy? He would quickly wipe that thought out of his mind. Still, it settled like a haze over everything he did.
Their sibling rivalry was intense, especially over toys.
So when he felt his brother approaching, after finally finding his lair in the desert, he couldn't properly think of what to do. He was supposed to have killed the spider, causing his brother tremendous pain. Now that he knew why his brother would be in pain, however, he wanted more than anything to keep this human all to himself. But this, no doubt, would make his brother fight all the harder. 'The lady or the tiger,' he'd think to himself. Should he kill the girl and cause his brother pain, or kill the girl and go without... He knew it wasn't really the same paradox, but his mind was clouded. He decided he'd sleep on it.
Well, he'd sleep with her on it, anyway.
"Nobody loves me, it's true...not like you do."