Well she sounded just like Piper from her time, always wanted to know exactly what was going on in a voice that would stop anyone dead in their tracks. Billie turned slightly, keeping herself positioned ever so slightly infront of Christy, one hand reaching backward slightly to touch her on the arm, as if she was trying to make sure she was still there, and not running away.
"She," Billie said, offering up at least part of the explanation- she wasn't even touching the Prue issue, it wasn't her place to do so "is Christy, and I'm Billie, we're sisters." as if that part wasn't already obvious, it had to be pretty obvious. "We're both witches- obviously. With a lot of power. When we were kids the Triad had her kidnapped and they raised her. You and your sisters are called the Charmed Ones, but Christy and I are called the Ultimate Power. Or magic can rival yours, and the demons knew this. So they took her and raised her to later get to me, so we could take you down." she did her very best to ignore any look the Christy was probably giving them right now. "Anyway- it didn't work, I didn't side with the demons in the end, and well...that ended up splitting us up again, for a while, and the demons were vanquished. But...well, she sort of blames you for it." and in a way it probably was her fault, but as far as Billie was concerned, she was glad it was Pipers fault.
"You'll meet me eventually, probably about five or so years into the future." she tried to explain, "And she," Billie said, looking to Paige "Is Paige, my Whitelighter, but also half Witch- your half sister."
Had she chose to side with the demons, there was a very real chance that everyone but her and Piper would be dead. Or, if she had gone back and done things differently, that the Charmed Ones could have lost. The two blonde sisters were packing a lot of power. They may not have been as experienced as the older sisters, but they were learning and their powers were growing rapidly. Billie's Projection was getting stronger all the time, you didn't want to mess with Christy and her fire. They weren't a team to be taken lightly, but Billie didn't want them as rivals to the Charmed Ones. She wanted to be allies.
[ooc: order switch for Billie and Christy. Christy will be next!]