|“||...I'd say that, in the 40-odd years I've been doing this, I've never seen anyone fight longer or harder than Casey Rance. You might just be the strongest person I've ever met in my whole life. Remember that. They don't get to win.||”|
Casey is the youngest of the Rance household. She is consistently worrying about her sister Katherine,as well as her father Henry Rance. She is depicted as a sweet and loving young girl in the first episodes of the series, but as time continues she becomes increasingly dark and removed.
- Since the television series is inspired by the original Exorcist novel, Casey's character is an updated version of Regan MacNeil.