I need help making an evil character for a story I'm writing?

Ok so i'm having trouble making an evil character for my story. The only things I'm sure of right now is that I want her to be female,immortal,a witch,and beautiful. I can't think of a bood name or any good looks for her yet. I already know that she is gunna be kinda slutty and really bad *** and mean so I already have her personality. So can somebody please help me out with a name and what she should look like? Answer fast please cause I'm kinda stuck because I can't get passed her introduction.