Billie missed Christy, to put it simply.
She had thought about her so much in the past few years, created an image in her mind of what she might look like now. She pictured long, blonde hair, much like her own, and figured that Christy had probably taken on the features of their mother, since she had developed the features of their father.
Billie wondered if 'they' had harmed her. If every day was full of continuous torture, whether it was physical or emotional - and if they fed her, allowed her proper hygiene and clothing. It seemed doubtful, because really, why would demons go that far just to take care of a witch they were only using for their selfish purposes?
She had pondered about her sister so many times, so many days...that when she finally got her back, her senses blinded.
Occasionally, Billie would wonder if Christy ever really loved her, ever thought about her-- before she had turned evil. Billie thought it was probably likely (despite her pessimism on the subject), as they had been close, even at such a young age. Their time together had been so short, though. As had her time with her parents.
Christy had been innocent, it hadn't been her fault, however. Billie couldn't blame her. It had beem all The Triad's fault, and their stupid destiny's fault.
Billie hoped Christy went to heaven. She deserved it, despite what all she had done, because she had been ripped of her life.
Every now and then, she would look up at the sky, and the smallest one of Phoebe's daughters would touch her shoulder, asking her what she was staring at. Billie would smile, pet her head, and tell her to go play with her sisters and to never, ever let them go, and never, ever take them for granted. The little girl would nod vigorously, then skip off.
Sighing, she would turn her head back up to that huge mass of blue above her, then feel another hand on her shoulder. This time, it was Phoebe.
"I think she went to heaven," Phoebe would say softly, smiling slightly.
It almost made Billie laugh, how intuitive Phoebe was. After a moment, she would always reply, "Yeah, me too."
Even though she had lost a lot, she realized, they all had. The Charmed Ones had lost even more than her, probably. But in a sense, Billie had gained a lot as well, she had gained friends, a Whitelighter and a boyfriend in one (they had all laughed greatly at the fact, and Piper had informed her on all the things she would need to know on how to sneak things passed The Elders), new experiences, more knowledge and wisdom of the world, and even a new family.
Snatching her eyes away from the odd-shaped clouds, Billie turned to see that Phoebe, Coop, and their children were getting ready to leave to go to the manor for Wyatt's sixteenth birthday party.
"C'mon, Billie! You gotta hurry, I wanna get there before Aunt Piper cuts the cake!" Prue, Phoebe's oldest daughter, yelled to her.
"Okay, you guys go ahead, I'll follow you!" Billie took one last glance at the sky, before getting in her car. Smiling to herself, she knew that her parents-- and even Christy-- would be proud, and even though there were still many things to be lost, there were still so many things to be gained, too. And somehow, she knew everything would be alright.