The Doctors mortal enemy is a timelord who goes by the name of "The Master". A genius whose soul aim in life is conquest of the universe. The Master has been played by three actors.

Master 1 - Played by Roger Delgado until his tragic death in a car accident in Spain. He was by far my personal favourite - making the character look totally evil.

Master 2 - Played very competently by Anthony Ainley until the end of the television series.

Master 3 - Roberts played The Master in the new Dr Who feature film.