Billie Jenkins

Billie Jenkins is the deuteragonist and temporary secondary antagonist of the eighth and final season of Charmed. She is a friend of Piper Halliwell, Phoebe Halliwell and Paige Matthews who was manipulated by her sister, Christy into believing the Charmed Ones were not worthy are of their powers. However, Billie realizes they are being used by their childhood "Imaginary friend" Dumain and sides with the sisters in the final battle and is forced to kill her own sister when she realizes Christy is beyond reason. 
After reconciling with her friends, Billie becomes an honorary aunt to Phoebe's children.
She inherited witch powers by her maternal grandmother. The character was created by executive producer Brad Kern and was portrayed by Kaley Cuoco.