The Master

The Master, like the Doctor, is a Time Lord. To use an Earth literary analogy, he is somewhat of a Moriaty to the Doctor's  Holmes. He has been described as "one of the most evil and corrupt beings (the) Time Lord race has ever produced ("The Five Doctors")."

The Television Series
The Master was one of the Doctor's classmates at the Time Lord Academy. During this time they appear to have been close friends ("The Sea Devils"). It was probably during this time that he also first met the Rani. The Master is generally believed to have had at least one antagonistic encounter with the Doctor prior to the Doctor's third incarnation.

The Master appeared at a circus ground on Earth in the 1970s, his TARDIS materializing in the form of a circus trailer or horse box. He promptly hypnotized the circus troupe to obey his orders, as part of his plan to assist the Nestenes in their latest bid to conquer Earth ("Terror of the Autons"). Over the next few years, he and his hypnotized or otherwise suborned followers engage in several attempts to conquer the Earth, often with the aid of alien invaders. However, his attempts were invariably foiled by the Doctor.

When the Fourth Doctor encountered the Master on Gallifrey, he had exhausted his supply of regenerations and was attempting to rejuvenate himself. Rescued from the planet Tersurus by Chancellor Goth, the Master nearly succeeded in acquiring the Eye of Harmony and using its energy reserves to renew himself. This theme of acquiring a new cycle of regenerations appears throughout the Master's later battles with the Doctor.

While on Traken the Master managed to take over the body of Tremas, Nyssa's father. In this new form, he continued his efforts to conquer the universe; but he was also focused on acquiring a new cycle of regenerations, rather than finding ways to take over new bodies.

Eventually, he was tried and executed by the Daleks; but he was somehow able to take over the body of an ambulance driver on Earth, in spite of having been reduced to a small quantity of fluid. ("Doctor Who: The TV Movie")

At the end of his battle with the recently regenerated Eighth Doctor, the Master fell into the Eye of Harmony, and was presumably destroyed. The Doctor claimed that he had been eaten by the TARDIS. It should be noted, however, that the Master has seemed on many previous occassions to be completely destroyed, only to return, becoming even more evil and dangerous each time.

The Expanded Universe

 * Following graduation from the Time Lord Academy, the Master, then known as Koschei, pursued a career as Magistrate for the High Council. In this capacity, his devotion to justic and discipline in time devolved into an obsession with order which marked the beginning of his descent into darkness ("The Infinity Doctors").


 * After the Doctor fled Gallifrey, Koschei was recruited to pursue and apprehend him. His unstable obsession with order however, prompted the Time Lords to plant the Time Lady Ailla as a spy to monitor Koschei's actions, posing as a human that Koschei takes on as a companion on a stopover in the 28th century. Koschei finally caught up with the Doctor at the Darkheart colony in the early years of the Federation. However, the enormous temptation instilled by the Darkheart device proved too much for Koschei, and the realization that Ailla was a Time Lord spy finally killed all last traces of good in him. Trapped in a black hole by the Doctor, Koschei, the Master, vowed revenge ("The Dark Path").


 * Sometime during his battles with the Third Doctor and UNIT, the Master attemtped to alter the events surrounding the assassination of American president John F. Kennedy, initiating events which would eliminate the existence of UNIT and possibly also the Third Doctor, leaving Earth vulnerable to conquest by the many alien races which threatened it during the later 20th century. ("Who Killed Kennedy")


 * While helping UNIT stop an invasion by the Inferno Earth, the Master met that alternate reality's version of himself, still using the name Koschei, imprisoned and vivisected by order of that reality's version of the Doctor. The Master mercy killed his other self. ("Face of the Enemy")


 * The Doctor later learned in his eighth incarnation that the Master exhausted his regenerative cycle recovering from injuries suffered on Tersurus in an explosion triggered by Susan Foreman when he attempted to kidnap her. ("Legacy of the Daleks").