As I said earlier, the three leading ladies have embodied these characters so well for so long that you can see they have incorporated parts of themselves into the characters and have also grown in the process.
The Triad identifies Billie as the Ultimate Power, which was foreshadowed in earlier episodes as the season's big bad, and refers to Christy as the key to unlocking Billie's power.
Oliver, Søren Oliver, and to destroy the Charmed Ones: Holly Marie Combs , Alyssa Milano , and Rose McGowan.
Ruditis followed this up in a later interview by calling Christy a pawn under the control of the Triad rather than a proper villain; he found that the series lacked a strong, female antagonist.
With the Halliwells' help, Billie attempts to help Christy reintegrate back into everyday life and to gain control over her powers.
Executive producer scripted the sisterhood between Christy and as a way to preserve the series' focus on family.