The Master (The Doctor's Universe)

The Master was a renegade Time Lord and nemesis of The Doctor.

Early Years:
The Master was a Gallifreyan boy, at age 8 he was shown the Untempered Schism and snapped, he was admitted to the academy and became close friends with The Doctor, when The Doctor fled Gallifrey with his granddaughter he thought he should leave too, stealing a Type 62 Tardis for himself, becoming one of The Four Renegades. (The other's being The Monk, The Doctor, and The Rani.)

He went on many adventures, spreading cruelty across the universe for fun and joy until he eventually encountered The Doctor on one of his many travels, The Doctor put a stop to him and he became angry, he began to use his regenerations and disguises to cause more pain before becoming his last self and facing The Third Doctor a large amount of times.

This version of The Master had his body destroyed after various adventures, he encountered the Fourth Doctor on Gallifrey and stole a Tardis, he began a crusade of stealing bodies.

As Xanxia:
After various attempts he eventually decided to seek revenge by stealing the body of Xanxia the Queen of Zanak, transforming her planet into a pirate ship of sorts and using her power to rob other worlds dry, he would remain in this body for a long time before being stopped by The Fourth Doctor, he escaped inside Xanxia's body and went to Traken, briefly stealing the body of the Trakenite Tremas, this body quickly burned out and The Master took his daughter's body instead, The Fourth Doctor brought the real Xanxia away until he returned and met The Master who had been tricked out of Nyssa's body and back into Xanxia's, This version of the Master would end up forcing The Fourth Doctor to regenerate.

Return as Nyssa:
After the death of The Doctor's companion Adric the Master attempted to steal The Doctor's body, failing he decided to rob Nyssa of her body once more, leaving his previous body in stasis. He would use Nyssa's body on a variety of adventures against the Fifth and Sixth Doctors, even "helping" the Time Lords on several occasions during the Immortality Incident and the Trial of The Doctor. In trade for a new regeneration cycle for himself.

The Master would fight the Seventh Doctor on a few occasions in Nyssa's body before storing her's in stasis and stealing various other bodies.

Fighting The Eighth Doctor:
The Master would be forced into becoming a Death Worm Morphant after a trial for what he'd done to the universe, he was to be taken to Gallifrey by the Doctor.

The Master escapes the Doctor after the death of his Seventh self and quickly steal the body of a paramedic named Bruce, Bruce's body would quickly disintegrate after a few hours, causing The Master to decide that the Doctor's body would be ideal, after stealing a few more bodies including Bruce's dead wife Miranda he enlists the aid of Chang Lee and tries to steal The Doctor's body, failing he fights The Doctor on a few more occasions after stabilizing his body.

The Time War:
He would continue to battle the Eighth Doctor into The Time War, The Time Lords eventually granted him a new cycle and asked him to fight in the war in exchange. He would use seven different bodies very similar in appearance to his first self before escaping to the End of The Universe and using a Chameleon Arch to mask himself as human.



Post Time War:
The Master would encounter the Tenth Doctor and regenerate into a new body, becoming Prime Minister of Great Britain under the name of Harold Saxon.

After taking over the Earth from turning the Doctor's Tardis into a Paradox machine, The Master died at the hands of his own human wife Lucy.

The Master chose against regenerating to claim a finale victory against The Doctor who wanted nothing more then the Master to live.

The Master would be reborn in Lucy's body through a cult, he killed the cult and fought The Doctor one last time before being brought to the last Day of The Time War by an attacking Rassilon who'd been trying to escape it.

Before Missy:
Little about his life before becoming Missy is known, what is known is the Master escaped Gallifrey and stole various bodies once again and made a failed alliance with a Mondasian colony ship.

As Missy:
The Master became a female naturally for the first time and went on to face The Twelfth Doctor a few times before finally admitting she wanted to turn a new leaf, The Doctor accepted and she eventually decided she'd turn good after an encounter with a previous version of herself, she was killed by her previous selves' Laser Screwdriver without a witness, the Doctor never knew about her sacrifice.