The Master has been played by multiple actors since the character's introduction in 1971, explained within the show as a consequence of regeneration, a biological attribute allowing Time Lords to survive fatal injuries.
The Master has been played by multiple actors since the character's introduction in 1971. The character's introduction in 1971 is explained within the show as a consequence of regeneration. Regeneration is a biological attribute. This biological attribute is allowing Time Lords to survive fatal injuries.