The Machavellian character of the Master has long been a thorn in the side of the Doctor and a staple part of the show.
It’s perhaps surprising that the Master character wasn’t actually introduced into the show, until Who was in its seventh season – in Spearhead From Space.
Some fans like to hypothesise that the Master character first appeared in the final Troughton episode – Wargames; under a previous regeneration but this has never been clarified.
Roger Delgado was a revelation, playing opposite his longtime friend – Pertwee. The Master gave the Doctor a recurring enemy of some standing. He was dangerously knowledgable, being a fellow Time Lord and completely ruthless in his scheming.
He and the Doctor had been contemporaries from their Gallifreyan academy days and friends and it was later hinted at, that they may have even been related.
An unfilmed story – due to Delgado’s untimely death. Which was to mark Pertwee regeneration and the Master’s exit; would have revealed the Master was actually a manifestation of the Doctor’s darker side. Something later wrapped up into the Sixth Doctor’s Valeyard character.
Apart from a brilliantly ruthless mind, the Master was also a gifted impersonator (with a line in convincing rubber masks) and a hypnotist. Which he used to recruit other beings to act out his will. Later on he developed a deadly tissue compacting device which left his enemies like shrunken dolls.
He had a more advanced and Chameleon circuit functioning Tardis, which he regularly used to blend into the surroundings and maintain his cover.
The Master has been played by 6 different actors between 1971 and 1996. Roger Delgado from 1971 – 73, Peter Pratt – 1976, Anthony Beevers – 1980, Anthony Ainley – 1980 – 89. Gordon Tipple & Eric Roberts – 1996.
Season Eight – 1971
Season Nine – 1972
Season Ten – 1972-1973
Season Fourteen – 1976
Season Eighteen – 1980-81
Season Nineteen – 1982
Season Twenty – 1983
Season Twenty-One – 1984
Season Twenty Two – 1985
Season Twenty Six – 1989