Lady Cassandra O'Brien.Δ17

Lady Cassandra O'Brien.Δ17 (or better known as Lady Cassandra) is a recurring antagonist in the TV series, Doctor Who. She appears in the episodes "The End of the World" and "New Earth". She claims to be the last pure human, but due to lots of surgeries she is now only skin with a face that is stretched in a frame.

She was portrayed by the American-British actress, Zoë Wanamaker.