6. The Master (Buffyverse & Doctor Who)
While both of these evil characters strive for domination, they are also very different. The Buffyverse Master was a centuries old vampire who had totally lost his human face and possessed powers beyond those of most Buffyverse vampires, including superior speed, strength and durability to the likes of Angel, Spike, Darla and Drusilla, in addition to more esoteric powers such as psychic sensory and hypnosis, as well as various mystical abilities. He succeeded in killing Buffy in the first season of the show, but she was revived. In the Whoniverse, the Master is the Doctor's antithesis he's a renegade Time Lord and a vastly intelligent master of preparation with a knack for all things technological and a hunger for power. He can anticipate the Doctor's every move much in the same way the Doctor does with so many of his foes.