In his seventeenth incarnation, (PROSE: Girl Power!) the Master originally looked old, having white hair and blue eyes. Though he started his life clean-shaven, (COMIC: Fast Asleep) he eventually grew a scruffy white goatee beard. (AUDIO: Beneath the Viscoid)
After use of the Chameleon Arch, he regressed into a baby. (AUDIO: The Heavenly Paradigm) When Professor Yana met the Tenth Doctor, he resembled a slightly younger version of his original self, having aged naturally as a human. (TV: Utopia)
