The Master of the Culling

General
"The Master" — known at times by various other aliases — was a renegade Time Lord, a power-hungry "lover of chaos" who served as both a friend and an opponent of the Doctor.

Friends from childhood and schoolmates at the Time Lord Academy, the divide between the Master's lust for power and the Doctor's empathy for lesser species would eventually pull the two farther and farther apart — to the point that the Master often sought to kill the Doctor. Despite this enmity, however, the two would on occasion act as allies, and both continued to yearn for their old friendship.

Like the Doctor, the Master fled from Gallifrey in a TARDIS of his own, and, having fully embraced his darker nature, would go on to pit himself against the Doctor and UNIT on many occasions. Having expended his original regeneration cycle, the Master survived in the ghastly form of a living cadaver, for some time, before exploiting the powers of the Source on Traken to steal the body of Tremas. He would continue his crusade to submit the universe to his will in a variety of stolen or otherwise-fraudulent bodies, from using Tzun nanites in order to gain new regenerations, to transferring his essence into a Deathworm Morphant, which allowed him to survive execution by the Dalek Prelature, and continue to survive by possessing a succession of human bodies.

Origin
The Master grew up on Gallifrey in the House of Oakdown, though he would later comment to Wilfred Mott, in his 28th Incarnation, that growing up on Gallifrey was not something one could call childhood, but "more a life of duty". The name he was born with was unknown and apparently consisted of thirty-two letters. Like all Time Lords, the Master was taken from his family at the age of eight for the selection process.

The 30th Master | Early Life
Finally killed after his laser screwdriver back-fired, the 29th Master regenerated into his final incarnation of his current life cycle. This incarnation of the Master (Michael Shepard) spent an extended period of time within the confines of his TARDIS, and thus, he made plans.

The 30th Master would first appear after crashing his TARDIS into the Capitol, on Gallifrey, where he was captured after crash landing. He was then imprisoned for previous criminal acts. From here, the Master spent one-hundred years confined within a secure timelord prison facility.

Escaping Prison
The Master proceeded to escape from the prison facility, after causing a Mass Prison Break; killing many authority figures, leaving through illegal means, where he would be hunted for the next fifty years, in order to recapture him.

Edge Space
The 30th Master would begin plotting against the Gallifreyan race -- The Timelords -- after he escaped to ‘Edge Space’ also known as, the Edge of Time and Space; a Black hole that would encompass the universe. Here, the Master entered the Black hole, within his stolen Temporal Hummer, where upon exiting the otherside of the Black Hole, he discovered that he had come to another, pocket-sized, universe; a different dimension; after he encountered a warrior race, known as The Arkun. The Arkun deemed him one of their enemies, simply due to his biological and physical traits, explaining that he looked and acted like their enemy; the Obulance.

The Arkun
The Arkun, were world destroyers, and planet cullers, and the Master realised that he could negotiate with them, and offered them numerous planets in replacement for his own life. The Arkun agreed to this, so long as the 30th Master would allow them entry into The Master’s original universe, and intern, The Master was allowed to begin his plans to give The Arkun the world’s they desired; in order to keep his life.

The Trip Home
From here, the 30th Master was sent back to his own universe, where he returned to Gallifrey; with different intentions. The 30th Master arrived on Gallifrey from this different dimension only a year after he had originally left, with help from The Other. The Master attacked the Gallifreyan Citadel, with help from previous debtors; inmates he'd unintentionally freed. Together, they isolated the Gallifreyan Citadel, that was previously weak from the First Time War, and took control of the minds of Presidential Stewards, and High Council members alike, having them do his bidding. Furthermore, during this time, he also took control of the minds of a Gallifreyan Assassin squadron, for their fighting skills, so that they could defend him; and also many Gallifreyan scientists for their knowledge of “the higher arts”.

Taking Control
Once he had control over the Citadel, he began purging the Citadel residential areas, and had many Gallifreyans allow him to build and develop a Temporal Gate that would allow him to bring fourth the Arkun to Gallifrey.

The Gallifreyan Archives
But, this incarnation of the Master had his own plans, he would proceed to enter the Gallifreyan Archives where he would steal any information they had to allow him to hone his mind controlling abilities; furthermore, he forced all Gallifreyan members of Authority to grant him an extra thirty regenerative cycles; meaning the Master had roughly 390 more incarnations for himself. After this he would dispose of the Gallifreyan high council members, and intern, he would discover that a Blue Box had finally arrived upon the planet surface.

Discovering the Doctor | The Second Time War
Fearing the Doctor would recognise him and disrupt his plans too early, he altered DuFont’s memories, and intern, sent DuFont out to meet the Doctor, explain the altered experiences he had, and then bring the Doctor back to the Citadel, as his War Incarnation; in order for them both to have a duel, with the Master ultimately hoping to finally turn his friend to the darkness within. This was the moment that many realised that the Second War had just begun. During this time, the 13th Doctor [ Zoe Susan Watts]  arrived on Gallifrey where she met with Presidential Steward DuFont. DuFont forced her to take up the mantel of the Warrior, and she ignored this decision, leaving it up to her predecessor, she then entered her TARDIS, and became her next incarnation.

Restoring Lives | Death of the 30th Master
Under the assumption, he was restoring that which he lost, and tired of having to find new ways of surviving, this incarnation of the Master, was eventually restored to life for good, after he stole over thirty new regenerative cycles, forcing the mind-bent High Council of Timelords to offer him thirty cycles, in preparation for a future conflict with the Arkun.

Intern, the Master would try to manipulate the conflict to suit his own goals. However, this would result in even more devastation across the timeline, near the end of the Second Time War, that the Master had not anticipated; due to this, the 30th Master was driven to such a state of terror that he fled to the end of the universe and turned himself into a human with a Chameleon Arch, once again. But, before he was able to replace his consciousness, he found himself killed in an attack by the Arkun [YT: The Culling, Episode 3]. But, the 30th Master was able to return to his TARDIS, where he regenerated into his next incarnation; he became the Vanguard Master.