The Vanguard Master

"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.

Early Life
After the war was won by the Nameless One, the 30th Master retreated in fear. He was attacked by Arkun warriors as he escaped; suffering a devastating energy blast to his sternum. Before his death, the 30th Master was able to regenerate into his 31st incarnation - and now with unlimited lives - the Master had nothing to loose.

He turned himself into a human with his chameleon arch, taking on the name Da'vante Pope and nestling his way into the ranks of Torchwood Eleven. In time, they learnt to trust him. He spent thirty three years on Earth in this incarnation, working his way up through Torchwood and honing his intelligence; but, his personality would reawaken when he found himself about to be attacked by a Time Entity.

His pocket watch called to him, and intern, he opened it and reawakened his timelord consciousness; taking on the form of the Master again. He locked down Torchwood, taking over, and began turning Torchwood Eleven itself into a time bomb, with enough power to destroy the entire Earth.

Personality
This incarnation was far wackier, yet remained a malevolent force to be reckoned with. For a short time, he wreaked havoc across constellations, destroying stars and committing mass genocide; receiving the name 'The Vanguard' in doing so.