The Doctor (Doctor Who) footage. Tom Baker did reappear, but as "the Curator", an ambiguously different character who he was not credited for playing. A voice actor, John Guilor, recorded a line of audio impersonating the First Doctor, for which he was credited as "Voice Over Artist". In other multi-Doctor stories, the multiple actors are all credited as "The Doctor", the exception being "The Three Doctors" (1972–73), which credited William Hartnell, Patrick Troughton and Jon Pertwee as "Doctor Who" as the 1972 serial preceded the practice of crediting the character as "The Doctor". In "Human Nature" (2007), the plot involves the Tenth Doctor altering
The Master (Doctor Who) The Master (Doctor Who) The Master is a recurring character in the British science fiction television series "Doctor Who" and its associated spin-off works. The character is a renegade alien Time Lord and the archenemy of the title character the Doctor. The Master has been played by multiple actors since the character's introduction in 1971. Within the show, this is varyingly explained as the Master taking possession of other characters' bodies, or as a consequence of regeneration, a biological attribute allowing Time Lords to survive fatal injuries. The role was originated by Roger Delgado in 1971, who portrayed the Master