30. The Master, 'Doctor Who'
He's the Doctor's fellow Time Lord, and the entire multiversal spacetime continuum ain't big enough for the both of them. Created to be the Moriarty to the do-gooding Doctor's Sherlock Holmes, the Master has seen a number of incarnations over the course of the long-running British sci-fi series, from Roger Delgado's Satanic approach to John Simm's Tory-sociopath vibe. ("He" is currently a woman, played by Michelle Gomez.) But no matter who plays him or what he looks like, his goal is clear: Conquer the universe, and make the Doctor pay while doing it.