The Master

The Master, later the Mistress (Missy for short), was a renegade Time Lord and the Doctor's arch-enemy. He went by many other temporary aliases.

Although they were originally boyhood friends (TV: The Time Monster, The End of Time, PROSE: The Dark Path), one of the Master's primary goals was to destroy the Doctor and Earth while acting on a number of schemes, both petty and gross. (TV: The Deadly Assassin, Castrovalva, Time-Flight, Doctor Who)

The Master was referred to as a "jackanapes" and an "unimaginative plodder" by the Third Doctor (TV: Terror of the Autons), the "quintessence of evil" by the Fourth Doctor (TV: The Deadly Assassin), "one of the most evil and corrupt beings [the] Time Lord race [had] ever produced" and that his "crimes [were] without number and [his] villainy without end" by High Council President Borusa (TV: The Five Doctors), "pure evil" by the Eighth Doctor (TV: Doctor Who), "stone-cold brilliant" by the Tenth Doctor (TV: Last of the Time Lords / The End of Time), and "the Time Lords' most infamous child" by Time Lord founder Rassilon. (TV: The End of Time)

The Master's diabolical madness was at least partially the result of a genuine malady in the form of a never-ending drumming sound that had been retroactively implanted inside his head by the Time Lords on the last day of the Last Great Time War to further their own goals. (TV: The End of Time)

Early life
The Master grew up on Gallifrey in the House of Oakdown. (PROSE: Divided Loyalties) The Master and the Doctor shared the same heritage and upbringing. (AUDIO: UNIT: Dominion)

Despite his childhood being more a life of duty, (TV: The End of Time) he had a friendship with the First Doctor. (GAME: Destiny of the Doctors) The two youths would play in the fields near the young Master's home which was his father's estates, with pastures of red grass near Mount Perdition. (TV: The End of Time) They used to sneak out of the Capitol and drink with the Shobogans. (PROSE: The Eight Doctors) On one of these outings, the young Master picked a fight with six drunken Shobogans. (PROSE: UNIT Christmas Parties: Christmas Truce)

Like all Time Lords, the young Master was taken for his initiation at the age of eight. During the ceremony in which he gazed into the Time Vortex through the Untempered Schism, he went mad, which was not uncommon, as when Time Lords saw the Untempered Schism they either "went mad or ran away". This malady manifested itself as the constant drumming he heard ever after, worsening with time. (TV: Utopia, The Sound of Drums, Last of the Time Lords) Unknown to him, the drumming had been implanted retroactively into his mind by Rassilon as a link to later free the Time Lords from the time-lock imposed upon them. (TV: The End of Time)

During their childhood, the young Master and the Doctor had been mercilessly and viciously bullied by a boy called Torvic; the young Doctor was eventually forced to kill the bully to save his friend's life. He was later confronted by the personification of Death, who insisted he become her disciple. The Doctor refused and suggested Death make the Master her champion, to which she agreed. The Doctor had subsequently forgotten about his deal, but subconsciously, felt partly responsible for the Master ever since. (AUDIO: Master)

At the Academy, the Doctor and the Master were also part of the Gallifrey Academy Hot Five, in which the Master played the drums. (PROSE: Deadly Reunion) The Master would also hypnotise people, likely as a joke, but anyone he did hypnotise the Doctor could un-hypnotise. (PROSE: The Dark Path)

Whilst at the Academy, the Doctor and the Master travelled into Gallifrey's past in search of Valdemar. They found nothing of the Old Ones except for warnings. The Master was fascinated by the power that Valdemar represented while the Doctor was horrified. (PROSE: Tomb of Valdemar)

According to one account by the Master himself, during a period of civil unrest on Gallifrey, he led many students of the Time Lord Academy in a revolt against the corrupt Lord President, Pundat the Third, and attempted to recruit the Doctor and convince him to take the position as President, but he decided not to interfere with the current constitution. When Pundat died of stress soon after the revolt, his chosen successor was the evil Chancellor Slann. The students had found the last of Lord Rassilon’s descendants, Lady Larn, a seven-year old child adopted by Councillor Brolin, who was being groomed as a future president. They decided on a second coup. Yet in trying to convert the Doctor, the students were overheard. Bloody reprisals against the students followed. The Doctor and Larn escaped from Gallifrey after this. Believing the students ready for the second coup, the Master assassinated Lord President Slann. However, the students weren’t ready and he took this opportunity to steal a TARDIS and flee Gallifrey as a renegade. (PROSE: Birth of a Renegade)

Dealings with the Second Doctor
After the First Doctor fled Gallifrey in his stolen TARDIS, the Master left Gallifrey on the same day, (COMIC: The Glorious Dead) surprised to find no one chasing him. However, his unstable obsession with order prompted the Time Lords to plant the Time Lady Ailla as a spy to monitor his actions. She posed as a human so Koschei (as the Master had now started calling himself) would take her on as his companion during a stopover in the 28th century.

Koschei caught up with the Second Doctor at the Darkheart colony in the early years of the Galactic Federation. The temptation posed by the Darkheart device proved too much for Koschei, and the revelation that Ailla was a spy killed the last traces of good in him, and he became the Master. After the Doctor trapped him in a black hole, the Master swore that he would take revenge. (PROSE: The Dark Path) The Doctor would later say that he and the Master had everything in common, but the Master enjoyed being scared of the dark a little too much, and it swallowed him. (PROSE: The Menagerie)

The Master put his TARDIS in orbit of the homeworld of the Archons and made a deal with them that would result in the Archons acquiring a TARDIS of their own, namely the Doctor's. Posing as a Professor Thascalos, the Master gave the Necronomicon to the Doctor's companion Jamie McCrimmon, so that Jamie would give the book to the Doctor and lure the TARDIS to the Archon homeworld. (PROSE: The Nameless City)

The Master penetrated Gallifrey, and gained access to the Matrix via a console in the old Capitol. This gave him a back door into the Matrix, which he used to collect classified information for his many devious schemes. (PROSE: The Quantum Archangel)

Nemesis of the Third Doctor
Before the Third Doctor was made aware by the Time Lords of his presence, the Master had in fact been on Earth for some time.

When the Doctor was exiled to Earth, the Master was imprisoned on Shada by the Time Lords. However, the Time Lords decided to keep the Doctor busy whilst he was trapped on Earth by releasing the Master. (PROSE: Prisoners of the Sun)

The Master was present at the first Auton invasion of Earth. He had apparently seen or heard about Channing's attempt to capture the Third Doctor. He contacted journalist James Stevens by phone, whose article he had read in the Daily Chronicle, and told him about the near-kidnapping.

He later called Stevens again, during the Silurian attacks on Wenley Moor. He informed Stevens that Frederick Masters had been the first to die from the plague sweeping London. Shortly after the Inferno Project incident, the Master once more contacted James Stevens, this time to check up on his work on his UNIT article. He promptly hung up when Stevens mentioned C19 and the Glasshouse. (PROSE: Who Killed Kennedy)

He first infiltrated the headquarters of UNIT while the Brigadier and the Doctor had gone to meet with government officials. He hypnotised the Doctor's assistant Liz Shaw and, through her, learned of recent events, including the recent failed Nestene invasion and the awakening of the Silurians. This inspired him to ally himself with them and to locate any more Silurian colonies. (PROSE: Reconnaissance) The Master invented the Keller Machine, and spent many months establishing his and its credentials. (TV: The Mind of Evil)

The Master appeared at a circus, his TARDIS in the form of a circus trailer or horse box. He hypnotised the circus troupe to obey his orders as part of his plan to assist the Nestenes in their latest bid to conquer Earth. A Time Lord emissary alerted the Doctor to his rival's presence on the planet. After the failure of his plan, the Master fled. The Doctor had already taken his dematerialisation circuit, however, preventing the Master from leaving Earth in his TARDIS. (TV: Terror of the Autons)

The Master returned again, posing as the scientist who had "developed" the Keller Machine (in reality a living alien entity). He used prisoners as a plan to hijack a missile containing nerve gas and use it to cause a conflict that would trigger a nuclear war. The Doctor stopped him and destroyed the missile, but later discovered he had lost the Master's dematerialisation circuit back. Shortly after, the Master telephoned to let it be known that he had found the circuit and was free now to come and go as he pleased, while the Doctor had to remain in exile. (TV: The Mind of Evil)

Shortly after the Master regained control over his TARDIS, he tried to gain control of a cult so he could harness the power of the Immortals. He convinced the real cult leader, Hadley, that he could serve the cult loyally, by supplying them with sarg. Unfortunately for the Master, Hadley only intended to keep the Master alive while he was still useful. With no other options, the Master formed a temporary truce with the Doctor to stop Hades' plan. After the crisis was resolved, the Doctor allowed the Master to depart unmolested in the name of their temporary truce. (PROSE: Deadly Reunion)

The Master eventually recovered full functionality of his TARDIS and brought Axos to Earth, hoping to ally himself with them. Instead, he became the prisoner of Axos, and only escaped by saying that he would help it. The Doctor tricked the Master into thinking he was going to betray Earth. Instead, he trapped the Master with Axos in a time loop. (TV: The Claws of Axos)

Utilising records stolen from the Time Lords, the Master, posing as an Adjudicator, travelled to a human colony on the planet Uxarieus in the year 2472. There the records indicated he would find the Doomsday Weapon created by a near-extinct native species. Once again the Doctor defeated his plans. (TV: Colony in Space)

In the Wiltshire village of Devil's End, the Master summoned the ancient Dæmon Azal, but he failed to understand the power and control that was necessary following summoning him. Following Azal's confrontation with Jo Grant's selflessness, he was captured by UNIT following a failed attempt to escape in the Doctor's car, Bessie. (TV: The Dæmons) After a trial by human authorities, the Master was sentenced to life-long imprisonment on an island off of the coast of England, one designed especially to hold him. (TV: The Sea Devils) The government used him as a scapegoat for all the alien attacks which had recently occurred. (PROSE: Who Killed Kennedy)

Prior to his trial, the Master was sent to Stangmoor Prison, but during his captivity, an army of hypnotised salespeople stormed the prison. This was an attempt to rescue him, but the attempt failed and the Master was sent to another secure holding facility. Meanwhile, the Doctor and Jo were trapped in an extra-universal prison by the Freedom Corporation, so the Brigadier was forced to strike a deal with the Master to save them. But the Master double-crossed him and used time travel technology to regress the Earth backwards in time. However, with help from the Time Lords, the Doctor was freed and was able to stop the Master's plan and restore everything to normal. (PROSE: Freedom)

Before he was sent to the island, the Master was sent to Aylesbury Grange Detention Centre. The Doctor visited the Master, who insisted he had changed, only to reveal he had escaped. The Doctor was speaking to a hologram. The Master nearly escaped, but was stopped by soldiers. The Doctor revealed he had been a hologram as well. (COMIC: The Man in the Ion Mask)

While in custody, with the Doctor gone to Peladon, (TV: The Curse of Peladon) the Master collaborated with UNIT to prevent an invasion by a fascist version of Earth, travelling with the Brigadier and Ian and Barbara Chesterton to that alternate universe and encountering an alternate version of himself. This alternate Master was imprisoned and tortured by order of the Leader of the Republic of Great Britain, that reality's version of the Doctor. The Master killed his other self, claiming it was an act of mercy. Before he was imprisoned by UNIT again, the Master hid his TARDIS back in the church crypt in Devil's End. (PROSE: The Face of the Enemy)

Some time during his obvious actions against the Doctor and UNIT, the Master infiltrated the government's Department C19 to a shocking degree. He took control of the Glasshouse, a facility for traumatised UNIT soldiers, and in particular Private Francis Cleary. He also tried to undermine UNIT in the short term. In the long term, he planned to use a time ring to have Cleary go to 1963 to prevent the Kennedy assassination, thereby altering Earth's history to make it more vulnerable to invasion. The plan failed. (PROSE: Who Killed Kennedy)

In a later encounter, the Master created a device that switched his mind with the Doctor's. He went to the Doctor's TARDIS, where he learned that the Time Lords had made the TARDIS unpilotable by the Doctor. Before returning to the TARDIS, the Master asked the Brigadier to move him to a new holding facility with a good view and told Mike Yates to ask Jo Grant out on a date. (PROSE: The Switching)

When he was finally sent to Fortress Island, the Master quickly gained control over his jailer, George Trenchard, and nearly caused a war between humans and Sea Devils, a species related to the Silurians. He later escaped in the confusion, (TV: The Sea Devils) and returned to the church crypt in Devil's End to retrieve his TARDIS. (PROSE: The Eight Doctors, The Face of the Enemy)

The Master posed as Professor Thascalos at Cambridge's Newton Institute, constructing a machine known as TOMTIT to summon an ancient creature that he wished to control. He hypnotised the institue's director, Dr. Charles Percival, noting he was one of the best and most obedient subjects he hypnotised. The Master accidentally killed him, however, by releasing the creature inside half of the Crystal of Kronos. The Master summoned the Atlantean priest Krasis for instructions on how to control the creature in the crystal, while meddling with the flow of time to obstruct the Doctor from getting in his way.

He later performed the what Benton called the "oldest trick in the book" on him- disguising his voice over the phone as the Brigadier to lure Benton into a trap. His impression was surprisingly correct, until the Master addressed Benton with "my dear fellow", his own speech habit. Benton caught on, quickly arriving at the institute, waiting to turn his gun on the Master and capture him. The Master responded by pretending that the Doctor had just entered the room. Benton turned around expecting to see the Doctor, and the Master knocked the gun out of his hand, then threw him into a filing cabinet, which knocked Benton out. The Master proudly declared, "You're wrong, Sergeant Benton. That is the oldest trick in the book!"

The Master retreated to his TARDIS, but the Doctor tried to trap him in a time lock using his own TARDIS, accidentally creating a space loop when both TARDISes were materialised within the other. When the TARDISes were separated during their negotiations, the Master ejected the Doctor into space. The Doctor survived by using the telepathic circuit of his TARDIS to help Jo return him to safety.

The Master travelled to ancient Atlantis and failed to hypnotise King Dalios, who easily resisted his influence. Confronting the Doctor there, he tried to manipulate Queen Galleia into betraying her husband, since she had taken a romantic liking in his charm compared to Dalios's often dull personality. Galliea, however, was enraged when the Master caused Dalios to die in the coup they staged in Atlantis. Before he was arrested, he commanded Krasis to use the Crystal of Kronos housed in Atlantis which he had obtained. He brought forth Kronos, king of the Chronovores, who destroyed the entire civilisation.

The Master captured Jo with the complete Crystal of Kronos. With Kronos under his control, the Master was in a position to cast great destruction unto the entire cosmos. The Doctor knew this and threatened to time ram the Master's TARDIS with his own, which would take everyone's lives in the process if he did not give up his plans for chaos. The Master did not believe the Doctor would earnestly carry out his warning, because he knew the measure of the Doctor's character. Endangering the life of a companion was not an option for him. In response to the Doctor's hesitation, Jo tried to complete the time ram before the Master could release Kronos again. Instead, Kronos spared everyone from death. However, taking the form of a female, Kronos captured the Master for the crime of trying to control it, but allowed him to go free at the request of the Doctor. The Master's enemy took pity on him when Kronos planned to make the Master suffer an eternity of torment. (TV: The Time Monster)

The Master employed the assistance of a being called Verdigris, who impersonated the Master, and was tasked with interfering in the Doctor's life. After Verdigris contacted him again, the Master told him that he had enough of Earth and had other plans to set in motion on Skaro. (PROSE: Verdigris) He forged a short-lived alliance with the Daleks, acting as their agent to provoke warfare between the Earth Empire and the Draconian Empire in the 26th century. To achieve this, he employed a force of Ogrons who, through the use of hypnosound, made themselves appear human or Draconian, thus provoking the other side. When the Doctor revealed the true perpetrators, the plot was abandoned. (TV: Frontier in Space)

The Master set up a talent show called Make a Star, which he used to disrupt the timeline by making the contestants cover songs that weren't yet written. He intended to use the relatively minor disruption caused to allow him to take control of Earth, but this plan was foiled by the Doctor. (PROSE: Hidden Talent) On another occasion, the Master made a deal with the Odobenidans to help them invade Earth, but accidentally trapped both them and himself in a time loop whilst undertaking some temporal mechanics on their behalf. He was trapped in the time loop beneath Greece for months. The Time Lords sent the Doctor to Greece so that the Doctor would deal with the time loop, where he released the Master and foiled his plan again. (PROSE: The Seismologist's Story)

Returning to Earth, the Doctor uncovered another plot by the Master to release a fog in Tadcaster by using Sarkan mist-flowers to generate the fog. If they bloomed, their seeds would spread and the Earth would be covered in the dense fog. Attempting to catch up with the Master, the Doctor commandeered the pier train. They jumped off the train as it reached the end of the tracks and crashed into the Master and the mist-flowers, sending all of them into the ocean, where the flowers were destroyed and the Master disappeared. (COMIC: Fogbound) Reappearing again, the Master took control of the Brigadier's mind, and instructed him to kill the Doctor. However, this plan failed and the Brigadier attacks the Master. He escaped, restoring the Brigadier to his senses. (PROSE: Smash Hit)

The Master once travelled to the Land of Fiction, where he intended to steal an advanced piece of technology from the Land, and met characters like Professor James Moriarty and Count Dracula. (COMIC: Character Assassin)

The Master used time-displaced Scottish warriors to seize a nuclear submarine and threaten Britain with obliteration if he wasn't given the Doctor's TARDIS; he ended up temporarily trapped in the 18th century. (COMIC: The Glen of Sleeping) He also worked with the Gaderene race to conquer Earth. (PROSE: Last of the Gaderene)

For a short while the Master adopted the identity of Duke Dominus, a gangster on early 20th century Earth, but his plan on this occasion was halted by the Fourth Doctor without the Master even knowing it. (PROSE: The Duke of Dominoes)

A body in decay
The Master finally went under cover on Earth following the 22nd century Dalek invasion and killed David Campbell, the husband of the Doctor's granddaughter Susan. After being defeated by the Eighth Doctor, he fled in his TARDIS, taking Susan with him as a hostage, unaware of her Gallifreyan heritage. As his TARDIS materialised on Tersurus, she used his TARDIS' telepathic circuits to attack him, forcing him out onto the planet's surface. She used his own Tissue Compression Eliminator against him while he was holding the Dalek's matter transmuter. The blast severely deformed and nearly killed him. Susan departed in his TARDIS; this brief materialisation, however, alerted the Time Lords to the Master's presence on Tersurus. (PROSE: Legacy of the Daleks)

Investigating the materialisation of an unauthorised TARDIS, the Time Lord Chancellor Goth arrived on Tersurus, where he found the Master in a wasted condition — that of a decaying animated corpse. The Master sensed that Goth wished for power and offered it to him, whilst Goth, thinking that the Master was a dying "creature," thought he could control the Master for his own means. (PROSE: Legacy of the Daleks, TV: The Deadly Assassin)

The Master made Goth, in line for the position of Lord President of the High Council of Time Lords, into his slave, continuing to promise him power. Whilst on Gallifrey, he also took over the mind of Solis, one of the Chancellory Guard. With a telepathic summons and a vision of the future created by the Matrix, the Master lured the Fourth Doctor to Gallifrey, seemingly to prevent the murder of the then-serving Lord President. The Doctor failed and ended up on trial for the President's murder. Whilst the Doctor was on trial the Master killed others on Gallifrey through the use of his Tissue Compression Eliminator, leaving them to be found like a grisly calling card for the Doctor.

Secretly, the Master had access to the Matrix. He also had guessed the secret of the Eye of Harmony and various artefacts left behind by Rassilon. He realised that the Eye of Harmony, a black hole, resided beneath the Panopticon and, realising that it had immense power, believed he could use the Sash of Rassilon to protect himself from the raw power of the Eye and the destruction that unleashing it would cause. He thought that he could channel that energy to renew himself.

The Doctor defeated the Master in physical combat, and as a result, the Master appeared to have fallen into a crevice created by a localised earthquake. In fact, he had gained access to his TARDIS, disguised as a grandfather clock, and escaped. (TV: The Deadly Assassin)

Immediately after leaving Gallifrey, the Master attempted to rend asunder the constellation of Mandus using a segment of the Key to Time. The Master also entered a pact with the Embodiment of Gris. (PROSE: Cold Fusion) With his TARDIS still in the form of a clock, the Master tried to steal Iris Wildthyme's body. (PROSE: The Scarlet Shadow)

The Master had entered into an alliance with the Kraals, and claimed to help them invade the Earth in 1979. (AUDIO: The Oseidon Adventure) He tried to achieve this by looking for a genetically engineered alien worm, whose purpose was to generate wormholes in space. The worm had been living in Derbyshire for centuries and had passed into folklore, however; it had taken the form of a woman called Demesne Furze. While he was looking for the worm, he allied himself with Colonel Spindleton, where they both met the Fourth Doctor and Leela. However, the Master generated a storm, using a lightning bolt from it to activate the worm's ability to create wormholes, in turn, generating a wormhole to Oseidon, but also killing the worm. (AUDIO: Trail of the White Worm)

Upon arrival on Earth, the Kraals, led by Marshal Grinmal, double-crossed the Master and imprisoned him with Leela, while they sent the Doctor to Oseidon to be interrogated by Chief Scientist Tyngworg. However, the Master and Leela escaped through the wormhole and infiltrated the Kraal bunker. While he was in the bunker, the Master discovered he was an android duplicate, ever since he arrived in Derbyshire, and the Master had been on Oseidon all along, impersonating Tyngworg. During this, the Doctor escaped and reprogrammed the androids to destroy the invasion force. But as the Master tried to deactivate all the androids, he discovered he was susceptible to the signal, and therefore, he had also been an android all along as well. The Doctor and Leela constructed another duplicate of the Master in order to help them discover the real Master's plan. The Master plotted to capture the Z-battery that the Doctor left on Earth to repair his TARDIS during his exile. The Master's plan was to use the Z-radiation within the battery, combined with the O-radiation which permeated Oseidon, to create powerful ZO-radiation which the Master could use to renew himself. The Doctor defeated the Master by using the Master's android duplicate he had constructed to kidnap the Master, and take him away in his own TARDIS, before his plan could be fulfilled. (AUDIO: The Oseidon Adventure)

Discovering that the Celestial Intervention Agency were gathering illegal Vess weapons, the Master blackmailed their agent, Straxus, into handing over a Conceptual bomb, the Master visited Bob Dovie and, after killing his family, planned the device into his head. When Dovie saw the Fifth Doctor's TARDIS, his refusal to believe in it caused the Doctor's TARDIS to explode. With the Doctor's timeline collapsing in on itself, the Doctor's first eight incarnation joined forces to Time ram the Master's TARDIS into a Pocket dimension, before the First Doctor erased the events from history. (AUDIO: The Light at the End)

The Master was drawn to and became stranded on the planet Traken, the centre of the Traken Union, in a TARDIS configured into the sculpture-shaped Melkur. The Master plotted to take over the Source also located on the planet Traken, the power behind the Traken Union, and use it to restore himself. To this end, over a period of years, he won over Kassia, who later married Tremas and became a stepmother to Nyssa. His plans were thwarted when the Keeper summoned the Fourth Doctor and Adric, who had sensed something of his machinations. With the help of Tremas and Nyssa, the Doctor removed the Master from the Source. However, with some of the Keeper's powers lingering, the Master merged with Tremas, stealing his body. (TV: The Keeper of Traken) However, because Tremas's body was not that of a Time Lord, it could not regenerate but would age instead. If he wanted to survive, the Master would have to steal another body. (TV: Logopolis)

In Tremas' body
The Master, in his new Trakenite body, went to Earth, where he trapped the Doctor's TARDIS in a gravity bubble. He killed Tegan Jovanka's aunt Vanessa and a police constable with his Tissue Compression Eliminator. He went to Logopolis, where he pretended to be Tremas to get Nyssa's cooperation, giving her a bracelet that allowed him to control her arm. Using her as a hostage, he perverted the Block Transfer Computations and held the planet for ransom until its secret was revealed. This made the causal nexus unravel and release an unstoppable wave of entropy to destroy the universe. He also broke the Logopolitans' blockade of entropy, allowing it to swallow several galaxies, including the entire Traken Union.

The entropy wave was so threatening that the Master agreed to work with the Fourth Doctor to stop it. They travelled to the Pharos Project on Earth to do so, using the last theorem of Logopolis to reopen Charged Vacuum Emboitments, or CVEs. His true plan was revealed however, when he sent a message to the peoples of the universe that he would stop the entropy only if they submitted to his rule. While stopping the Master's signal to shut down the CVE that would halt the entropy wave, the Doctor fell off the Pharos Project's radio telescope and regenerated, allowing the Master to escape. (TV: Logopolis)

The Master kidnapped Adric and held him in a hadron web to make him a part of his TARDIS. Using a projection of Adric on board the TARDIS, the Master sent the newly-regenerated Fifth Doctor hurtling to destruction at Event One, but the Doctor saved his TARDIS through the Architectural Configuration. The Master used Adric's block transfer computations to create Castrovalva in the Andromeda Galaxy, where the Doctor would recover from his regeneration. He escaped from the recursion trap and tried to kill the Doctor, but was attacked by the enraged citizens with the city itself due to collapse. (TV: Castrovalva)

The Master escaped from Castrovalva, but in the attempt, it caused damage to the dynamorphic generators, making it difficult to continue piloting his TARDIS. (PROSE: The Quantum Archangel)

In an attempt to capture and kill the Doctor and his companions, the Master arrived in England in the 1920s, and manipulated Harry Houdini to send a psionic distress call to his old friend. When the Doctor answered the call, Houdini claimed that he needed help to stop a fortune teller. However, when the Master's plan was uncovered, the Doctor managed to stop his arch-enemy's revenge plan. (AUDIO: Smoke and Mirrors)

He travelled to Earth in 140,000,000 BC, where he disguised himself as the magician Kalid, hoping to use the Xeraphin gestalt to replace his dynamorphic generators. He brought two Concordes to his Citadel via a time contour. The second held the Doctor, his TARDIS and companions. He originally planned to use the captured passengers to break into the Sanctum and take control of the Xeraphin and add him to his TARDIS, but then he acquired the Doctor's TARDIS in a trade with him for a part the Doctor needed for his own TARDIS.

The Xeraphin contacted Nyssa and let Tegan and her enter the Citadel, where he revealed his true form. The Master held the passengers hostage for parts from the Doctor's TARDIS. The second Concorde was returned to its own time and the Master ended up on Xeriphas with the freed and angry Xeraphin. (TV: Time-Flight) On Xeriphas, he found and acquired Kamelion, a shape-changing android that could be easily controlled by a stong mind. Managing to elude Xeraphin, the Master escaped to England in 1215. He disguised himself as the French knight Sir Giles and made Kamelion impersonate John of England to prevent the signing of Magna Carta. However, the arrival of the Doctor caused interference with his plans. After the Doctor defeated him in a joust, the Master fled in his TARDIS after the still-disguised Kamelion offered the Doctor the choice of saving him or another captive. (TV: The King's Demons)

Directly following these events, the High Council of the Time Lords discovered that earlier incarnations of the Doctor had been taken into the Death Zone on Gallifrey. They asked the Master for help and offered him a new cycle of regenerations. He agreed and was given a copy of the Seal of the High Council by the Castellan. The Doctor's third incarnation did not believe him and took the seal from him. He made a temporary alliance with the Cybermen to guide them to the Dark Tower. He informed the First Doctor how to get past security, but then grew power-hungry at the mention of immortality. Brigadier Lethbridge-Stewart knocked him unconscious and Sarah Jane Smith and Tegan Jovanka bound him. After Borusa was encased in Rassilon's tomb, Rassilon sent the Master back to his own time. (TV: The Five Doctors)

As an attempt to trap the Doctor, and steal his remaining regenerations, the Master faked his own death, ensuring the Doctor would attend the funeral at the nursing home where he supposedly spent his final days. But the Doctor was saved by Turlough, and the Master's plan was foiled yet again. (PROSE: The Velvet Dark)

The Master arrived in Camelot just after the coronation of King Arthur. He became the Merlin after the old one had died. He planned to make Arthur believe Mordred was dead so Mordred would grow up to kill Arthur at the battle of Camlan.

The Doctor and Tegan arrived, met Arthur and told him about the Master. Arthur summoned the Merlin to test their truthfulness. When the Master saw the Doctor and Tegan, he told Arthur he had no intention of harming him. He left the court and hurried to his TARDIS, which was disguised as the turret room of Arthur's castle. The Doctor suggested Arthur create the Knights of the Round Table so when Mordred came they would be ready. (PROSE: The Creation of Camelot)

The Master developed a more powerful version of the Tissue Compression Eliminator and accidentally shrank himself and his lab, without the ill effect of death. Using a device to boast his telepathy, the Master made contact with Kamelion once more, directing him to use the Fifth Doctor's TARDIS to land on planet Sarn. With Kamelion acting as his physical proxy, the Master had him pretend to be the locals' god and order the Doctor's death. When this failed, he had Kamelion take the small box his lab had become and take it to the lab on Sarn that used Numismaton Gas, hoping it could restore him. As the Master stood in a gas vent and returned to normal size, the Doctor used the gas to burn him (apparently) to death. (TV: Planet of Fire) However, the Numismaton Gas increased the power of the Source of Traken still remaining in the Master body. (PROSE: The Quantum Archangel) He went in search the Fountain of Youth to restore himself, which he managed to exploit. (PROSE: A Town Called Eternity)

A hallucination of this incarnation of the Master appeared to the Fifth Doctor as he lay dying of spectrox toxaemia in the TARDIS. (TV: The Caves of Androzani) This was due to the Master's attempts to psychically interfere with the Doctor's fourth regeneration. (AUDIO: Winter)

The Master allied with the Rani (whom he knew as a member of the Deca on Gallifrey) in Killingworth, an early 19th century English mining village, against the Sixth Doctor and Peri Brown; he hoped to hasten the advancement of Earth's technology for his own nefarious reasons while the Rani wanted the brain chemical that induced sleep. The Doctor trapped the Master and the Rani in her TARDIS, which the Doctor had sabotaged; time spillage put them in danger of being eaten by a tyrannosaurus rex. (TV: The Mark of the Rani) The Master separated the Rani's console room from the rest of her TARDIS, leaving her to drift aimlessly through the vortex. (PROSE: State of Change)

Working with Adam Mitchell, the Master set up a asylum in 7214 with Autons as staff as a trap for the Doctor, Peri and Frobisher. The Doctor broke out of his cell thanks to Peri and Frobisher and melted the Autons. The Master escaped by tripping up the Doctor, leaving Adam to capture Peri. (COMIC: Prisoners of Time)

Recovering his own TARDIS and learning of the Valeyard, the Master materialised in the Matrix and observed the Sixth Doctor's trial on Space Station Zenobia while examining the Matrix footage himself to see what was tampered with. He considered the Valeyard a rival and rescued the Doctor rather than have the Valeyard win as the darker version of his foe was someone he believed unbeatable. He used Sabalom Glitz, always ready to work with anyone for a quick grotzit, as a tool. He tried to steal secrets from the Matrix, but he was double-crossed by the Valeyard, and imprisoned in the Matrix with a limbo atrophier. (TV: The Ultimate Foe) The Time Lords released the Master from the Matrix, whereupon the Master killed the technicians and fled in his TARDIS. (PROSE: Mission: Impractical) After escaping, the Master could regenerate his body because the Source of Traken still existed within him. (PROSE: The Quantum Archangel)

After escaping from an unsuccessful alliance with the Krotons, the Master discovered that the last remnants of the Source of Traken were fading, so his previous cadaverous form would return and he would die. Meanwhile, he was attacked by the Chronovores looking for revenge after he tortured Kronos. The Master devised a plan to destroy the Chronovores and achieve omnipotence by trying to access the Lux Aeterna using the son of TOMTIT, the TITAN Array. He stole the equipment and used it upon a woman he hypnotised, Anjeliqua Whitefriar, expecting it to destroy her before he used it. However, she absorbed the Lux Aeterna, achieved omnipotence and became the Quantum Archangel. Using her power, she filled the universe with too many alternate timelines, leading the Chronovores to feast upon them, eventually leading to the end of the universe. The Master (fully returned to his cadaverous form again) and the Doctor teamed up to rectify the Master's mistake by defeating the Quantum Archangel. They discovered that the Quantum Archangel had allied itself with the Mad Mind of Bophemeral so it could have infinite knowledge of the Universe. The Doctor and the Master encountered Kronos, who claimed to have been the one who attacked the Master's TARDIS, so he would come up with his plan, and would eventually lead to the Master's destruction as well as allowing Anjeliqua to survive, causing Kronos' plan for revenge to go wrong. They succeeded by draining the Lux Aeterna out of her, although not before the Master escaped using the TITAN equipment to harness the Lux Aeterna to restore his Tremas body. (PROSE: The Quantum Archangel)

After trying to start a war between Antari Two and Antari Three, (PROSE: First Frontier) the Master went to the Cheetah World, where he took control of the Cheetah People and the kitlings. He sent them to Ace's home in the London suburb of Perivale and hunted for human recruits. At the same time, exposure to the planet was changing him into a Cheetah Person. He found a pliable young man called Midge and used him to escape.

Using Midge as his "hunting dog", he recruited a gang of Perivale youths to defeat the Seventh Doctor and Ace. The Master killed Midge and teleported the Doctor to the Cheetah World, which had begun to break up. The Doctor escaped but the Master was trapped on the dying world. (TV: Survival)

After Cheetah World
How exactly the Master escaped the Cheetah World was a matter of debate. Several competing theories existed.

Finding a new regenerative cycle in the past
One idea about the Master's escape from Cheetah World had it that he escaped with the aid of a Kitling just as the planet exploded. The explosion of the planet sent him back in time to Earth in 1957.

Trapped on Earth at the dawn of the Space Age, the Master interrupted the real first Soviet satellite launch and sent a distress signal to the Tzun Canton on Zeta Reticuli Four. He offered to help assimilate Earth into the Tzun Confederacy. In return the Master asked for passage off Earth and the use of the Tzun's genetic engineering to cure his Cheetah Virus infection. The Tzun accepted and prepared nanites for him that broke down the corrupted Trakenite DNA in his cells and restructured it. This restored the Master to being a "full" Time Lord, which gave him a new regenerative cycle. While assisting the Tzun, the Master used the alias Major Kreer. Shortly after being restored to his full Time Lord heritage he was shot in the back by Ace, causing him to regenerate. Following the regeneration he was able to make his escape, summoning his TARDIS using a Stattenheim remote control built from Tzun technology. After leaving a booby-trap for the Seventh Doctor in a nuclear warhead, the Master fled. (PROSE: First Frontier)

Later, the Master laid a trap for the Doctor in one of the Doctor's homes using a device which would release the energy from a time fissure once the Doctor's TARDIS materialised. This would destroy it. The plan failed when Sarah Jane Smith, Mike Yates and K9 destroyed the device, causing the Master to flee. (PROSE: Housewarming)

The nanites the Tzun gave the Master eventually began to fail, causing him to seek the Loom of Rassilon's Mouse in order to make himself a new body. The plan failed and the Master managed to escape by hypnotising Kitai into posing as a decoy. (PROSE: Happy Endings)

Tremas persists
Another theory held that the Tremas Master simply continued to exist after his time on Cheetah World, and that he remained infected by the Cheetah Virus for quite some time. On Earth, he tried to cure the virus by extracting nutrients from dying humans. (PROSE: Stop the Pigeon) The Master next tried to gain a new body from legendary aliens, the Fleshsmiths. The Master's plan was stopped by the Doctor, who ejected the new body from the Fleshsmith vessel into space. (PROSE: Prime Time)

According to this version of history, it wasn't at all clear how the Master rid himself of the virus that had so plagued him, but he got rid of it by the time of his second alliance with Adam Mitchell. At this point he used a group of Aeroliths to further his alliance. He syphoned their life force, to transmit to his "partner", using a Gulwort. However, when they were freed by the Seventh Doctor, they chased the Master. (COMIC: Prisoners of Time)

Eventually, the Master captured the first seven of the Doctor's incarnations and put them into a void called the Determinant. The Graak freed the Doctors and the Master was put on trial by one of the races involved in his game. (GAME: Destiny of the Doctors)

Tremas lost
A third account failed to touch on any ill-effects of the Master's interaction with the Cheetah People. Focused instead on the latter part of the Tremas Master's life, it suggested that at some point, the Master learned of a device known as the Warp Core, a sentient powerhouse of mental energy designed as a weapon to safeguard the planet Duchamp 331. He tracked the Warp Core to Earth, intending to use it to power his TARDIS. Unprepared for its power and underestimating its outside awareness, he was attacked by the Warp Core, having the body he stole from Tremas stripped from him, reducing him to his previous, decaying form. The Master then used a mask to disguise his deformity and followed the Warp Core as it arrived on Duchamp 331. (AUDIO: Dust Breeding) The Seventh Doctor made a deal with Death whereby the Master would have ten years of peace and sanity, at the end of which the Doctor had to kill him. The still-scarred Master had become a physician on the colony world of Perfugium with no memory of his past, and took the name John Smith. He was taken in by Wolstonecroft, and inherited his house when Wolstonecroft died. During his ten years as John Smith, the Master had become emotionally involved with Jacqueline Schaeffer.

At the end of the allotted time, the Doctor duly arrived but strove to avoid fulfilling his side of the bargain. The Master became aware of the Doctor's role in pledging him to Death as her servant but forgave him for it. Death herself was present, disguised as the Master's maid, and manipulated events so that the John Smith persona would crumble and the true Master become dominant once more. (AUDIO: Master)

Stealing the Doctor's lives
When the Master, then in his "final incarnation", (TV: Doctor Who) arrived in the Valley of the Kings in Egypt, he was captured by the Daleks to be placed on trial, but his TARDIS was left behind in the tomb. (AUDIO: Mastermind) After he was tried and executed by the Daleks on Skaro as part of a Time Lord-Dalek treaty, (PROSE: Lungbarrow) the Master's last and, in the words of the Eighth Doctor, "somewhat curious" request was for the Seventh Doctor to transport his remains to Gallifrey. (TV: Doctor Who) However, his essence survived in a fluid-like form that was known as a Deathworm Morphant. (COMIC: The Fallen, PROSE: The Eight Doctors, AUDIO: Mastermind)

The Seventh Doctor stored the ashes in a casket and set his TARDIS on course for Gallifrey. En route, the Master, whose consciousness had survived the death of his physical body, escaped from the casket and interfered with the TARDIS, causing a timing malfunction. The ship materialised in San Francisco during the final days of 1999.

On exiting the TARDIS, the Doctor was caught in a crossfire of a gang war and was picked up by an ambulance. As he lay wounded, he saw the Master's form exiting the TARDIS via its keyhole, but he was unable to communicate this information to the humans nearby. While Bruce tended to the Doctor and loaded him into the ambulance, the Master hid inside a bag. After Bruce had gone to home and bed, the Master forced his way into Bruce's body through his mouth, killing him and taking over his body.

The next morning, the Master awoke, now inhabiting Bruce's body. He realised the decaying form would not last long and launched his scheme to steal the Doctor's remaining regenerations. His first act was to kill Bruce's wife.

The transformation into Bruce involved some complications. His eyes retained the "cat's eye" appearance, forcing him to wear sunglasses to remain inconspicuous. Also, Bruce's body began to decay rapidly.

The Master befriended Chang Lee, a young gang member who had been present when the Doctor was shot, and who had stolen the TARDIS key. With Lee's help, he entered the Doctor's TARDIS and regaled Lee with stories of the Doctor's supposed villainy (claiming, among other things, the Doctor had stolen the Master's regenerations). As part of his plan to take the Doctor's lives, he intended to open the Eye of Harmony, destroying the Earth in the process. With Lee's further help, he was able to open the Eye. He discovered that the Doctor had regenerated into a new form, and that the Doctor was half-human. This answered a few of the Master's longstanding questions about his foe. (TV: Doctor Who) The Eighth Doctor revealed to Chantir in prison that he tricked the Master into thinking this, with a "wide eyed expression, a couple of words, and a half-broken chameleon arch." (COMIC: The Forgotten)

The Master tracked the Eighth Doctor down, pretending to be Bruce, and agreed to take the Doctor and Dr Grace Holloway to Professor Wagg's atomic clock at the Institute for Technological Advancement and Research, to which Grace was a member of the board of trustees, and repair the timing malfunction the Master caused with the clock's beryllium chip. The Doctor escaped, but before he could do so, the Master secretly possessed Grace's mind. When the Doctor got back to the TARDIS to fix the timing malfunction, the Master had Grace knock the Doctor out and put him in restraints. He killed Lee by snapping his neck when Lee realised the truth about the Master after the Master accidentally revealed that he had wasted all of his lives in fighting the Doctor, rather than the Doctor having stolen them. The Master then forcibly opened the Eye using Grace's retina (freeing her from possession and returning her human eyes) so that he could steal the Doctor's lives.

Although the Master was able to initiate the transfer process that would give him access to the Doctor's remaining lives, Grace was able to prevent this by rerouting the TARDIS' power and sending the ship into a temporal orbit. Grace released the Doctor from his restraints, but the Master threw Grace off of a balcony inside the Cloister Room, killing her. With the Master's body dying as the Doctor's regenerations were returned to him, the two Time Lords fought near the Eye of Harmony, culminating in the Master falling into it when he leapt at the Doctor and misjudged the angle. After the TARDIS brought Lee and Grace back to life, Lee asked what had happened to the Master. He heard a strange rumbling sound coming from the TARDIS and the Doctor responded, "Indigestion." (TV: Doctor Who)

Shortly after his defeat, the Master laid a final trap for the Doctor, leaving a crystalline structure on the Eye that would give the Doctor amnesia. However, the Doctor was subconsciously guided by Rassilon to recover his memories, Rassilon helping him travel to various locations where the Doctor could make contact with his younger selves and regain his memories through telepathic contact, eventually being restored to normal. (PROSE: The Eight Doctors)

Beyond the Eye of Harmony
An "echo" of the Master imprisoned inside the Doctor's TARDIS offered the Eighth Doctor advice through a portrait, a mirror and later the Eye of Harmony. (PROSE: Sometime Never..., The Deadstone Memorial, The Gallifrey Chronicles) Whilst exploring the Eighth Doctor's TARDIS, River Song thought she heard an American screaming from within the walls. (GAME: The Eternity Clock)

The Master escaped through the Eye of Harmony by influencing the dreams of Edward Grainger to unravel the Doctor's timeline, by killing Edward Grainger whilst he was an infant in 1906. However, the Master was stopped by the First Doctor and Violet after being hit with a rolling pin and being removed from the body he possessed.

The Master then managed to evade the Eighth Doctor's detection, and possessed the body of a human native named Richard. (PROSE: Prologue, Forgotten)

After possessing Richard, the Master killed Violet out of revenge. However, the Master discovered his possession had caused the host body to decay at an accelerated rate, so he was forced to steal more bodies to prolong his survival. Realising that the First World War was rapidly approaching, the Master decided to migrate to America to avoid the conflict, and boarded a ship to go there in 1912. However, the Master boarded the RMS Titanic, unaware of its eventual fate, and escaped in a lifeboat when it sank.

Arriving in New York City, the Master took possession of a member of the Hudson Dusters, quickly becoming the leader of the gang and calling himself Don Maestro. After twenty years of living in his current body, he occupied the body of his host's son, and moved to Las Vegas where he owned a casino. He accumulated the money to fund his experiments, in an attempt to elongate the lifespan of his host body by forty years. Fearing the eventual decay of his body, the Master used his money to buy a penthouse to isolate himself from infection, so he had longer to live. After years living in isolation, his host's son confronted him, realising that the Master had possessed his father and his grandfather for decades. He then trapped the Master in the penthouse.

After UNIT infiltrated the sealed penthouse, they discovered the Master in a self-preserving comatose state. He was imprisoned in the UNIT Vault, awakening every five years for one hour, before going into a coma again. After fifteen years living in the Vault, the Master awoke again, and was interrogated by UNIT officers Ruth Matheson and Charlie Sato. However, the Master had managed to hypnotise both of them, and escape his imprisonment. He also discovered that UNIT had recovered his TARDIS from the Valley of the Kings, which had been there for three thousand years, and used it to escape from the Vault. (AUDIO: Mastermind)

Another account shows that the Master passed through the Eye of Harmony, and his essence was left wandering the Time Vortex and close to extinguishing. Eventually he was rescued from the Vortex by a being named Esterath, the then-controller of the Glory, the focal point of the Omniverse. The Master was told that it was time for the Glory to gain another controller, but the power had to be fought for. The Master assumed that the battle would be between himself and his greatest foe, the Doctor.



After gliding over the many realities throughout the Omniversal Spectrum for what he described as seeming like centuries, the Master was resurrected into the body of a recently-deceased vagrant on the streets of 2001 Brixton. Some weeks afterwards, the Master was transported onto the Moon during one of the Doctor's adventures (due to a symbiotic link he had formed with the Doctor's TARDIS, when it consumed part of his essence after he passed through the Eye of Harmony). The Master subsequently used this link to trail the Eighth Doctor for some time without his enemy suspecting — even after they had met face-to-face. (COMIC: The Glorious Dead)

He was present in London during the crisis resulting from Grace Holloway's attempt to merge human and Time Lord DNA (the alien DNA was in fact that of a Morphant). He killed an MI6 agent with the TCE at this time, but fortunately for the Master the Doctor departed before his trademark was discovered. (COMIC: The Fallen)

The Master later made contact with Sato Katsura, a Japanese samurai unwillingly rendered immortal as a result of his involvement in the Doctor's adventures. The embittered warrior became the Master's follower. At his behest, Sato adopted the identity of Cardinal Morningstar and became leader of the Church of the Glorious Dead, instigator of a holy war that altered the history of Earth, a planet now renamed "Dhakan".

The symbiotic link between the Doctor's TARDIS and the Master had also given the latter the ability to influence the flight of the TARDIS, which he used to send the craft to times and places which would weaken the Doctor's self-belief and confidence. This done, the two fought for the Glory, with the Master apparently triumphant.

It would soon be time for the Glory to gain another controller, but the power had to be fought for. The Master assumed the fight would be between himself and his greatest foe. He was mistaken. The true battle was between his companion, Sato, and the Doctor's, the Cyberman Kroton. Kroton was the victor. Amongst his first acts as controller of the Glory were to cleanse the TARDIS of the Master's influence and to place the Master somewhere that he could not escape. The Master declared he would survive and return. (COMIC: The Glorious Dead)

Preparing for War
The Master was rescued from "a predicament" and was given a new lease of life by the Time Lords. The Master presumed that they were "softening him up for something". Originally intending for him to fight against the Daleks, the Time Lords discovered that the Eminence posed a greater threat, and instructed him to use them to fight the Daleks. The Celestial Intervention Agency gave the Master all the information he needed for his mission.

The Master travelled to the Nixyce system and stole a teleportation casket of the Eminence, integrating it into his TARDIS console. He then tried to use the casket to gain influence over the Eminence, and take control of its infinite warriors, calling them his "finite warriors". (AUDIO: Eyes of the Master) He saved Sally Armstrong from being hit by a taxi, recruited her, and began to work for the Ides Scientific Institute in the 1970s. (AUDIO: Time's Horizon) He tried to discover why some humans were immune to the Eminence's influence, and eliminate it so that the Daleks could not exploit it.

The Master encountered the Eighth Doctor in London, and the Doctor opened his link to the Eminence located in his mind, teaching it how to pilot a TARDIS. The Eminence then used the teleportation casket located in the Master's TARDIS to pilot it, taking the Master and Sally with it. The Master managed to isolate the Eminence inside his TARDIS through the telepathic circuits, and Sally expelled the Eminence into the Time Vortex.

Some time later, Sally and the Master kidnapped Molly O'Sullivan from her home in 107 Baker Street. (AUDIO: Eyes of the Master)

Impersonating the Doctor
At a later point, the Master infiltrated a Time Lord base which contained the Node Stone, which was a product of dimension technology, developed by the Dimensioneers, and stole them. The Master attempted to control the dimensional energies using the Node Stone, by planting one of the Node Stones on the planet of the Tolians, to drain all the energy that was available. This was a way of drawing the Doctor to the Tolians' planet, so he could gain possession of the only other Node, which the Doctor had in his TARDIS. By manipulating the Tolians, he tricked the Doctor into re-supplying dimensional energy to the Tolians using his Node, which caused a catastrophic imbalance in dimensional energy, threatening the structure of reality itself.

The Master attempted to infiltrate UNIT by pretending to be a future incarnation of the Doctor, modelling his TARDIS on the police box exterior. He had to work alongside the UNIT scientific advisor, Elizabeth Klein and work under the command of Colonel Lafayette. He assisted UNIT in defeating a number of interdimensional alien incursions, including the Mind Leeches, Lava Spiders, the Nexus and Skyheads.

When the Doctor and his companion, Raine Creevy, fell through a dimensional doorway caused by the dimensional instability, the Master stole the Doctor's Node Stone, and sent all the alien invaders back to their own dimensions, but not before he left with the Doctor in his TARDIS. It was at this point that the Master revealed his true identity, and his plan, which was to use the two Node Stones to add even more dimensional energy to the Tolians, so he could use them to conquer the Earth and other planets beyond. However, the Doctor managed to convinced the leader of the Tolians, Arunzell, that the Master would betray his species. This gave the Doctor the opportunity to capture the Master, use the two Nodes to send the Tolians back to their own dimension, and then destroy both Node Stones, but not before the Master escaped during the ensuing chaos, intending to try his scheme all over again. (AUDIO: UNIT: Dominion)

Under the chameleon arch
The Master was resurrected by the Time Lords to fight in the Last Great Time War, believing him to be a perfect warrior, due to his savagery. He was present when the Dalek Emperor took control of the Cruciform. Frightened by the horror of the Time War, he ran away as far as he possibly could, to the end of the universe. (TV: The Sound of Drums) There, he used a chameleon arch to hide himself as a human, Professor Yana. (TV: Utopia) The War Doctor was sent by Rassilon to find the Master, but was unable to do so. (PROSE: Engines of War) Physically human, Yana believed that he was found on the coast of the Silver Devastation with only an "heirloom" fob watch. His memory of his past was that the watch could never keep time and was always late for things. He believed that he spent his life moving from one refugee ship to another and all his life he heard the sound of drums every waking hour as if they were getting closer. However, it was likely that none of what Yana believed about himself was any more true than that which, for example, John Smith gave to Joan Redfern.

Yana retained the Master's brilliant intellect and ultimately became involved in the attempt to send the remnants of humanity to Utopia. He eventually became friends with another scientist, Chantho, who was thought to be the last of the Malmooth race. Together, they worked on the Utopia Project to convey the surviving humans from the planet Malcassairo to Utopia. Yana met the Tenth Doctor, Jack Harkness and Martha Jones, who spoke phrases curiously familiar to him, phrases such as Time Vortex, "extermination", Time War, Daleks and regeneration. Martha made the Professor aware of a watch in his possession. Hearing voices in his mind that commanded and entreated him, he opened it and returned to his true identity.

He then attacked his assistant, angered that Chantho was too inept to return his memories after decades. He had also grown sick of her presence as he waited to be restored. Vengeful, he electrocuted her with a loose set of power cables, leaving Chantho for dead. However, Chantho used the last of her strength to pull a laser gun on the Master while his back was turned, and shot him in the chest before she succumbed to death. Fatally wounded, the Master regenerated into a younger incarnation and escaped to Earth in the Doctor's TARDIS. (TV: Utopia)

Becoming Harold Saxon
With his new body, the Master left the Doctor on the planet Malcassairo with Futurekind about to burst in the laboratory door. The Master now had the TARDIS and the Doctor's hand (which Jack Harkness had taken with him to Malcassairo) that contained the Doctor's DNA. (TV: Utopia) Because of the Doctor's last-minute intervention, the TARDIS would only take the Master to Earth in the 2000s. There, he began fabricating Harold Saxon's past to gain political support. He made his first public appearance about eighteen months before the Doctor reunited with his companion Jack Harkness, shortly after the downfall of Harriet Jones. The Master unveiled the Archangel Network, which was hailed as a telecommunications breakthrough. By this point he had taken the identity of Harold Saxon, complete with a fabricated past. (TV: The Sound of Drums)

By December 2007, he had become Minister of Defence of Great Britain. On Christmas Eve, he came to real prominence for the first time, ordering British Army tanks to destroy the Empress of the Racnoss' webstar. (TV: The Runaway Bride, The Sound of Drums)

In 2007, he campaigned for the general election as Prime Minister of Great Britain (TV: Love & Monsters) with the slogan "Vote Saxon". (TV: Captain Jack Harkness) He visited his old high school during the campaign, and as Harold Saxon did not exist, he used the Archangel Network to brainwash staff to gain political support. One teacher, James Curtis, was resistant to the Network, so the Master used his laser screwdriver to implant the appropriate memories into his mind. (PROSE: Speech Day)

Around the same time, Captain Jack Harkness discovered that Torchwood files were being "given" to the Opposition leader, by the Prime Minister. This was presumably "Saxon," attempting to learn more about Captain Jack and other confidential information. (TV: Greeks Bearing Gifts)

"Saxon" asserted that extraterrestrial life did exist and Britain must do something about it. With his election a sure thing, politicians from other parties flocked to his side.

The Master started the Archangel Network. This telecommunications network, tied to mobile phones, carried a mind control signal which made humans trust him. The network affected the Doctor so he had no suspicions as to the Master's presence as "Saxon", though he would have normally noticed the presence of another Time Lord. To those few humans conscious of it, the signal was a persistent drumbeat, the constant drumbeat the Master always heard, that only they could hear.

He also designed the Valiant, UNIT's air carrier, and a laser screwdriver which he reserved for his own use. (TV: The Sound of Drums) "Saxon" funded the rejuvenation experiments of Richard Lazarus. (TV: The Lazarus Experiment) "Saxon", along with all other incarnations of the Master, was also kidnapped by the Sild. (PROSE: Harvest of Time)

The Master contacted the Toclafane, the child-like, vicious cyborg remnants of the future humans who had never found Utopia. To allow the Toclafane to escape extinction and live anew in the past, he cannibalised and converted the Doctor's TARDIS into a paradox machine to change history. (TV: The Sound of Drums / Last of the Time Lords) After Martha had left with the Doctor, he had an agent meet with Martha's mother, Francine, who tapped into a conversation between Francine and Martha via the superphone, which could contact Martha through space and time. (TV: 42) Before the Doctor, Martha and Captain Jack arrived back from the end of the universe, (TV: Utopia) the Master had sent Jack's Torchwood team on a wild-goose chase to the Himalayas.

"The Master of all"
In 2008, he was elected Prime Minister. He announced first contact with the "friendly" Toclafane who could protect Earth against alien threats. Though he kept up appearances with the public, the Master began to deal with private matters severely. He gathered his Cabinet for a meeting and accused them of being traitors who abandoned their political parties to jump on his political ticket. He rigged the deskphone speakers on the Cabinet Room table to release a lethal gas that killed the Cabinet ministers, while using a gas mask to protect himself and mock his victims. He later unleashed the Toclafane on Sunday Mirror reporter Vivien Rook, who threatened to expose his fabricated past to the public.

The Master moved to the Valiant, which the governments of Earth considered neutral territory and therefore fitting for formal first contact with alien life. The Master had the Toclafane murder the President of the United States, Arthur Coleman Winters. He captured the Doctor, Jack, and Martha's family, who had come to the Valiant earlier that day. Using the results from Professor Lazarus's experiment along with the DNA in the Doctor's hand, he used his laser screwdriver to age the Doctor one hundred years.

The Master ordered the Toclafane to kill one tenth of humanity and commence their invasion. (TV: The Sound of Drums)

Martha escaped capture on the Valiant and travelled the world. One year later, in 2009, the Master had converted Earth into a slave camp which he ruled from the Valiant. The Master aged the Doctor even further and planned to expand his New Time Lord Empire into space. He built an army of warships to take his war across the universe.

Martha used the legend of the Doctor, which she had spread, and the thoughts of Earth thinking "Doctor" at the same time. Their psychic energy was channelled through the Archangel Network, which the Doctor had spent a year infiltrating telepathically. The psychic energy restored the Doctor and gave him telekinetic powers.

Jack destroyed the Paradox Machine and reversed time one year, although this did not affect anyone aboard the Valiant. Lucy shot the Master. Defeated, he refused to regenerate rather than receive the Doctor's mercy. He died in the Doctor's arms. (TV: Last of the Time Lords)

As far as the general public knew, Harold Saxon "went crazy" and disappeared, along with President Winters. (TV: The End of Time)

Raised from the dead
The Master was resurrected when his wife Lucy Saxon was imprisoned at Broadfell Prison, London. One of the warders, Miss Trefusis, retrieved the Master's ring from his funeral pyre. On Christmas Eve 2009, the prison governor brought Lucy to a chamber where most of the staff were members of the Disciples of Saxon, who had been working ever since his apparent death to bring about his resurrection.

With the help of the ring and a biometric imprint taken from Lucy, the Master reappeared in a swirl of energy, but Lucy and one other warder had prepared for this. To stop his resurrection, Lucy hurled a Potion of Death at the Master. His followers and Lucy were all killed in the resulting explosion.

The Master survived the blast, but his physical form was flawed: his once brown hair was now bleached blond, and he was unshaven and unkempt. Also, his life force was left in a state of constant depletion. He consumed huge quantities of food and drained the vitality of humans to stay alive. As a side effect of the failed resurrection, he could expend his life force for enhanced agility and send bolts of energy from his hands. The Master's body would even fluctuate between a fleshy form and a half-skeletal state. At times when his life force dipped to near depletion or he expressed strong emotion, his outer skin would fade away and reveal the translucent blue life energy encasing his body. This exposed his skeleton and internal organs, and each fluctuation made an unsettling noise likened to an abominable, primal roar. He led the Doctor on a wild goose chase after banging the beat of the drums in his mind to lure the Doctor to him and escaped when Wilf interrupted the chase. Encountering the Master soon after, the Tenth Doctor discovered the drumming in his head was not a symptom of insanity, but real. Billionaire Joshua Naismith kidnapped the Master and enlisted his assistance to mend the malfunctioning Vinvocci medical machine, the Immortality Gate. The Master cooperated for his own purposes. He broke out of a straitjacket and flew into the gateway, which he had working a billion fold on the human template. The gateway sent out an energy pulse that transformed every human on Earth, except Wilfred Mott and his granddaughter Donna, into the Master Race — identical copies of the Master subservient to him.

The High Council of Time Lords made contact with the Master using the rhythm of the drumbeats in his head — the same rhythm as the Time Lord's heartbeat — and sent him a White-Point Star, found only on Gallifrey, to boost the signal. Fitting the diamond to a nuclear bolt to boost the signal, the Master tore open the time lock on the war, bringing back the Time Lords.

As the Lord President Rassilon and his council arrived through the Immortality Gate, the Master announced he intended to transplant himself into the entire Time Lord race, just as he had done to the human race. Rassilon, using his gauntlet, reversed the effects of the Master's transplantation, and watched as Gallifrey returned to the universe on a collision course with Earth.

The President revealed his plans from the final days of the Time War, but the Doctor stepped in with Wilfred's pistol. After some hesitation, he shot the nuclear bolt holding the White-Point Star, destroying the link. Rassilon prepared to kill the Doctor, but the Master told the Doctor to step out of the way. He unleashed his bio-electric blasts at the President, roaring that the Time Lords had manipulated him and made him the monster he had become, counting the beat of the rhythm that had resounded in his head and tormenting him all his life. The Time Lords, Gallifrey, and the Master then vanished in a burst of white light, and according to the Tenth Doctor, Gallifrey and the Time Lords were sent "back into [the] hell" of the final day of the Time War. (TV: The End of Time)

As Missy
The Master managed to escape from the pocket universe in which Gallifrey existed. (TV: Death in Heaven) At some point before escaping, the Master's dying body finally regenerated, though this time, the Master's new incarnation was female. As such, she adapted her name of the Master into the Mistress, or Missy for short.

Working with the Cybermen, Missy took over the 3W Institute, an organisation founded by Dr Skarosa to care for dead bodies, in order to create a Cyberman army of the dead. She uploaded dying minds to the Nethersphere; a virtual reality housed within a matrix data slice. This reality changed and rewritten the minds, removing their emotions before re-downloading them into their Cyber-converted bodies. (TV:Dark Water)

At some point, Missy gave Clara Oswald the Doctor's phone number, claiming it was a tech support line, leading to Clara becoming a companion of the Eleventh Doctor and subsequently the Twelfth Doctor. (TV:The Bells of Saint John, Deep Breath)

Missy went along the Doctor's timeline and greeted people who died in the Doctor's name, (TV: Death in Heaven) such as the Half-Face Man (TV: Deep Breath) and Gretchen Carlisle. (TV: Into the Dalek)

Finding herself "a bit busy", (TV: The Caretaker) Missy began to secretly monitor the Doctor and Clara, (TV: Flatline) such as when Earth was saved from a solar flare by a forest that grew overnight. (TV: In the Forest of the Night)

Missy met the Twelfth Doctor and Clara at one of 3W's mausoleums, which she hidden inside St Paul's Cathedral with dimensional engineering. First posing as a robot and sharing a kiss with the very confused Doctor she later reveals she had lied about the robot part just as the Cybermen were getting ready to unleash themselves on London. During this time Missy told the Doctor he knew who she was, though he had discovered she was a member of the Time Lords as she was using technology from their home world, he had no idea which Time Lord she was, until outside London; as the Cybermen roam the streets Missy says that her name was short for Mistress, which would make more sense in her current incarnation than going by her more well known moniker: The Master, revealing to the shocked Doctor her true identity. (TV: Dark Water)

Missy was captured by UNIT, and having tipped them off on the Cybermen's presence. She was taken onto Boat One along with the Doctor. However she sent out a signal to the Cybermen, who attacked the plane. Missy freed herself and disintegrated Osgood. Missy ordered the Cybermen to remove a piece of the fuselage, causing Kate Stewart and the Doctor to be sucked out. She then ordered the Cybermen to destroy the plane and teleported away. In the Nethersphere, Missy and Seb watched the Doctor free falling, and when Seb got overexcited, she casually disintegrated him. The Doctor found out from the Cyber-converted Danny Pink that she planned to have the rain fall again, killing humanity, who would be reborn as Cybermen. She later teleported into the graveyard that the Doctor had piloted his TARDIS into. Missy gave him control of the Cybermen, wanting him to use them as an army; in the hopes of proving their similarities. However, she was defeated with the help of Danny, who retained his emotions.

After the threat of the Cybermen had ended, Missy gave the Doctor false coordinates to the current location of Gallifrey, and suggested that she and the Doctor could travel there together. However, Clara, using Missy's own weapon, decided to kill her. The Doctor wouldn't let Clara kill Missy, having decided to kill her himself. Before he could fire the weapon, Missy was disintegrated by a rogue Cyberman, who was revealed to be the Doctor's old friend, the Brigadier. (TV: Death in Heaven)

Alternative timelines
In one universe, the Master was a Magistrate for the High Council upon graduating the Time Lord Academy, and he was still close friends with the Doctor. Over time, his devotion to justice and discipline devolved into an obsession with order which marked the beginning of his descent into darkness. (PROSE: The Infinity Doctors)

In a parallel universe, the Master was still a loyal Time Lord who went under the name Koschei. He was working for the Celestial Intervention Agency and travelled with a human companion called Ailla. They became stranded on Earth after defeating the Great Intelligence, and the Republic of Great Britain captured him for information. Ailla was killed and Koschei was tortured until all his regenerations were used up. Koschei died when he was confronted by the Master from N-Space, who turned off his life-support machine at his request. (PROSE: The Face of the Enemy)

In an alternative universe, the Master aided the Daleks in a war against the Time Lords. The war was being led by the Sixth Doctor, who was President of the Time Lords. Due to the aid of the Master, the enemy began winning the war. Rather than let them win the war, the Doctor activated the Armageddon Sapphire, which destroyed this universe and killed the Master. (PROSE: The Quantum Archangel)

In a different alternative universe, the Master cooperated alongside the Rani, the Monk and Drax to try to destroy the world using a DNA recombinator, turning the human race into a gestalt consciousness which could be used as a weapon to conquer the universe. (PROSE: The Quantum Archangel)

Personality
The Master was the polar opposite of the Doctor in almost every respect. Though he retained a brilliant Time Lord mind and all of the Doctor's wit and cunning, he possessed two fatal character flaws - he was arrogant and exceptionally vain, which almost invariably led to his downfall. However, it was also revealed that the Master hadn't always been like this: he and the Doctor were once good friends as children on Gallifrey. The Doctor believed that staring into the Time Vortex as an eight-year old child drove him insane and caused his personality to change. (TV: The Sound of Drums) It was, in fact, during that occasion that the High Council from Gallifrey's future sent the sound of the heartbeat of a Time Lord into the Master's mind, leading at least in part to his madness. (TV: The End of Time)

Thirteenth incarnation
When he encountered the Third Doctor, the Master was suave and debonair with a sardonic sense of humour. Being a haughty psychopath, he regarded most beings as his inferiors but had a mutual respect for the Doctor as a worthy opponent and his (almost) intellectual equal. (TV: The Sea Devils) He often found himself unable to kill the Doctor, because that would rid him of the satisfaction of defeating him. (PROSE: Legacy of the Daleks) The Master was also not above working alongside the Doctor when necessary, and even showed a certain respect to the Doctor's companions even if he still considered them inferior to his adversary (TV: The Claws of Axos).

The opposite nature of the two showed up not only in their goals and methods, but also in the most basic of ways. The Master at this point was often arrogant and impatient, taken to be rude towards all and showing no tolerance for stupidity. The Doctor, on the other hand, was kind, caring and, when asked, would actually take the time to explain what he was doing and why. The Master often lied and killed people, but he gave the impression that he saw murder as a regrettable necessity rather than a lifestyle choice. He also considered his quarrel with the Doctor to be something of a game. (TV: Terror of the Autons, The Claws of Axos)

While in Atlantis, the Master formed a relationship of sorts with Queen Galleia, remarking that she was beautiful and promising her power. Both she and Lakis commented that he had "the bearing of a God". (TV: The Time Monster)

Following his degeneration, he was mainly preoccupied with finding a way to regenerate. The vengeful and vindictive side of the Master was at its most apparent while he was in this state. This vengefulness came through by killing various fellow Time Lords on Gallifrey, and his eventual possession of Tremas. (TV: The Deadly Assassin, The Keeper of Traken) The Master felt a even stronger hatred towards the Doctor, once attempting a plan that would have destroyed all the Doctors, even future Doctors, due to the Doctor causing the Master to waste regenerations. (AUDIO: The Light at the End)

"Tremas" incarnation
After possessing Tremas, the Master was, deadly and sophisticated but became decidedly more flamboyantly evil, bombastic and futile than he had been. He was prone to laughing and reciting speeches. At this point in his life, the Master was devoted to kill the Doctor. (TV: Castrovalva, The Five Doctors, GAME: Destiny of the Doctors) The Rani said that his plans were so overcomplicated that if he walked in a straight line he would get dizzy. (TV: The Mark of the Rani) After he was infected by the Cheetah Virus, he seemed more calm and calculating. (TV: Survival)

"Bruce" incarnation
This incarnation of the Master was generally calm and sinisterly villainous, but was also capable of terrifying rage. After being exterminated by the Daleks, the Master took possession of Bruce and, after finding that his new body was not stable, became determined to steal the remaining lives of the Doctor himself. (TV: Doctor Who)

In this incarnation, he felt a pedantic need to correct people on bad grammar. The most noteworthy occasion was when he corrected Grace Holloway's "kiss as good as me" to "kiss as well as me". (TV: Doctor Who)

When his attempt to take the Eighth Doctor's lives was thwarted, the Master reverted to a more basic, brutal approach, attempting to smash the Doctor's head in with a staff positioned around the Eye, proclaiming that life was wasted on the living and rejecting the Doctor's aid when he was being pulled into the Eye. (TV: Doctor Who)

"Yana" incarnation
Under the human identity of Professor Yana, the Master was kind, considerate and polite, and dedicated to finding a way to save humanity at the end of the universe. However, after returning to his identity as a Time Lord, this incarnation of the Master proved to be cold, ruthless and vindictive, a contrast from his human form. In contrast to his next incarnation, he was always serious and dignified. (TV: Utopia) This incarnation was also a coward, preferring to run away and become a human being instead of fighting in the war. (TV: The Sound of Drums)

"Saxon" incarnation
By the time of his return from his Yana persona, the Master appeared after his regeneration to have gone more insane than ever, regressing to an almost childlike state of spitefulness and obliviousness. He instantaneously rejected a plea to listen by saying, "No. It's my turn. Revenge." (TV: Last of the Time Lords) In this instance, the Tenth Doctor, being aware of how dangerous the Master was, attempted to take on the role of a kind of mentor in an attempt to save the Master from himself, saying "I'm not here to kill him. I'm here to save him." He pleaded with him on numerous occasions to calm down, stop what he is doing, listen and look at himself. (TV: Utopia, The Sound of Drums, Last of the Time Lords)

The Master also had an exceptionally heightened sense of his own brilliance which is far more pronounced and blatant than that of the Doctor. He refers to himself in the third person as "your Lord and Master" on numerous occasions and in reciting a Bible-style verse of his own making to the Doctor, "...and so it came to pass that the human race fell, and the Earth was no more. And I looked down, upon my new dominion as Master of All and I thought it good", revealed a penchant for fancying himself as a god. (TV: The Sound of Drums) He also held Time Lords to be an absolutely superior race of life automatically assuming the privilege of altering history, on the principle of: "I'm a Time Lord. I have that right". (TV: Last of the Time Lords)

The Master was able to match the Doctor's keen wit and sense of humour. He remarked to the President of the United States when reprimanded for his audacious conduct contravening established first contact policy with regards to the Deep Breath (DWE)ll that paperwork - I think I left it down the back of the settee. I did have a quick look. I found a pen, a sweet, a bus ticket. Have you met the wife?" (TV: The Sound of Drums)

The Master also shared the Doctor's incredible technical know-how. He was able to construct his laser screwdriver from Earth components and miniaturise Richard Lazarus' genetic manipulation technology. He was also able to cannibalise the Doctor's TARDIS and turn it into the Paradox Machine. (TV: The Sound of Drums)

After his revival, the Master was more insane than ever. He acted like an animal, eating food like one and acting rash. He could be close to sane when talking to the Doctor and was sure he was not insane when the Doctor finally heard the drums he hated so much. At the very end of his life, his personality seemed to revert; when Rassilon tried to kill the Doctor, the Master sacrificed himself as he found Rassilon a common enemy. He used an unknown amount of his life-force to blast Rassilon and save the Doctor when he could have let Rassilon kill the Doctor and survived himself. (TV: The End of Time)

"Missy" Incarnation
Upon regenerating into the Mistress, the personality of this Time Lord took another sharp turn. She retained an obsession of sorts with the Doctor, referring to him as her boyfriend. (TV: Deep Breath) She also retained her hunger for domination, forging an alliance with the Cybermen and creating an army of them from Earth's dead. However, this was revealed to be a plot to convince the Doctor that they were not so different by giving him an unstoppable army with which to "right wrongs." She claimed that she wanted "her friend [the Doctor] back." Despite her desire to reconnect with the Doctor, Missy retained her previous incarnations' murderous and sadistic tendencies; demonstrating cruel pleasure at taunting her victims and asking them to "say something nice" before she killed them. (TV: Dark Water, Death in Heaven)

Relationship with the Doctor
The Master's relationship with the Doctor was one of the most complex known. He respected the Doctor as a worthy opponent, once offering to use a recently-recovered weapon to take control of the universe while offering to share it with the Doctor (TV: Colony in Space). As time went on, however, the Master became increasingly obsessed with proving his personal superiority, causing him to view the Doctor both as his greatest friend and his worst enemy. He expressed deep anger toward the Doctor, along with a desire for vengeance, saying "No, it's my turn, revenge, best served hot" (TV: Last of the Time Lords), and accusing the Doctor of causing him to waste his regenerations.

Although initially willing to work with the Doctor when the situation required it (TV: Terror of the Autons, The Claws of Axos), towards the end of his life, the Master absolutely refused to listen to the Doctor on any occasion. He evinced his vanity when the Doctor confronted him with the words "I forgive you", which he had been terrified of hearing because it would have significantly dented his pride due to the Doctor's status as his sole remaining peer affirming that he was wrong. (TV: Last of the Time Lords)

The Master also had a crippling fear of an all-powerful, God-like Doctor probably based around the Doctor's habit of challenging his old foe's grandiose self-image by constantly derailing his plans. (TV: The Mind of Evil) When the Doctor harnessed the psychic energy of the entire human race and effectively became a god, the Master was reduced to sobbing against a wall. (TV: Last of the Time Lords) After regenerating into the female incarnation Missy, she demonstrated a bizarre infatuation with the Doctor, referring to him as her "boyfriend" and apparently holding him responsible for her fate. Upon meeting the Doctor in his twelfth incarnation, she pretended to be an android and passionately kissed him. (TV: Dark Water) She later wanted to give him control of her army of Cybermen, but he refused and gave it to Danny Pink instead who stopped her plans. While surprised, Missy didn't try to stop the Doctor as he went to kill her to spare Clara Oswald from doing it with her last request being to "say something nice" to her, a request she makes of everyone she kills. The Doctor told her she wins but was spared from killing her by the Brigadier who, while Cyber-converted, retained his humanity. (TV: Death in Heaven)

Companions
Unlike the Doctor, the Master usually worked and travelled alone. On rare occasion, he was seen with companions. Examples included Ailla the Time Lord spy; (PROSE: The Dark Path) Chang Lee, a young human whom the Master met in San Francisco; (TV: Doctor Who) Katsura Sato, an immortal Japanese Samurai who helped the Master in his quest for Glory; (COMIC: The Glorious Dead) Sally Armstrong that helped him to use the Eminence; (AUDIO: Time's Horizon) Chantho, a female assistant and companion to the Master in his Professor Yana identity; (TV: Utopia) and Lucy Saxon, his wife, who was described as having travelled with the Master in the TARDIS in the same fashion as the Doctor and his companions. (TV: The Sound of Drums) However, Alia was the only companion he travelled with because he wanted to rather than because he had to; in all other occasions, he only had a companion because he required a human ally to achieve his goal, with Lucy Saxon providing a convenient cover to reinforce his assumed human identity.

Character conception and development
When conceiving the character, the production team had originally considered the idea of the Doctor having a female arch-nemesis rather than male one (this idea was later revived with the creation of the Rani). Later, they thought of the Master as the evil half of a single personality. The Master's name was dreamed up as another counterpart to the Doctor's — like that of his enemy, "Master" is an academic title. But this does not mean that the Master has a lesser academic degree than the Doctor, as in a Masters Degree. Both being Time Lords, they have the same level of education and are graduates of the Time Lord Academy.

In the Third Doctor's original final episode concept, Roger Delgado's incarnation of the Master would have redeemed himself and given his life to save the Doctor, after which the Doctor would have regenerated; however, this story was never developed due to Delgado's accidental death. Over thirty years later, this idea would be reused in The End of Time with John Simm's incarnation of the Master sacrificing himself to save the Tenth Doctor from Rassilon.

In The Deadly Assassin, writer Robert Holmes deliberately chose to show the Master in a "transitional" form in case future production teams wanted to bring back the character. This transitional form was used in The Keeper of Traken.

The Master was the villain in the early drafts of the 1977 television story The Talons of Weng-Chiang.

Is "Koschei" his true name?
The name "Koschei" has been developed in various novels. However, like the Doctor's name, the Master's actual moniker has never been revealed in performed Doctor Who.

Still, the name has a befitting Russian heritage. Koschei (rus. or Коще́й Бессме́ртный, "Koschei The Deathless") is an antagonist in Russian folklore. He is an immortal who hides his soul inside a needle, which is inside an egg, in a duck, inside a hare, in an iron chest which is buried under a tree on the island of Buyan. As long as his soul is safe, he cannot die.

How many Masters?
It has never been firmly established on screen how many incarnations of the Master have existed. The only number explicitly given by any narrative is that found in TV: The Deadly Assassin, where the Master is said to be near the end of his thirteenth and final life. In PROSE: Legacy of the Daleks, it's unambiguously established that Susan Foreman uses a combination of the Master's Tissue Compression Eliminator and her knowledge of the TARDIS to wreak devastating physical damage on the Roger Delgado Master, and the form portrayed by Geoffrey Beevers and Peter Pratt is merely the degenerated form of Delgado and not a wholly different incarnation.

Afterwards, Anthony Ainley's version of the Master takes over Tremas' body goes on to plague the Doctor until the original series' end. Despite no actual regeneration, it's technically a different form.

There are no narratives whatsoever which unambiguously define the relationship between the Ainley Master and those that follow him, meaning that it's impossible to assign numbers to the Master's forms, in the same way that we would with incarnations of the Doctor.

That hasn't stopped at least one non-narrative source from trying, though. The 2010 edition of REF: Doctor Who: The Visual Dictionary indicates that the Master played by John Simm is the seventeenth form. According to this theory, Derek Jacobi would be the sixteenth, Eric Roberts the fifteenth, and Anthony Ainley/Gordon Tipple the fourteenth. However, there's no narrative evidence to support any of the Visual Dictionary claims.

Off-screen relationships
Although they played antagonists onscreen, in real life Roger Delgado and Jon Pertwee were actually close friends. In interviews and convention Q&A sessions, Pertwee often cited the death of Delgado as one of the factors which led him to give up the role. (DOC: PanoptiCon 93, MM VHS 15)

Long before Tom Baker met Anthony Ainley during the filming of his last episode, he had lived with his brother, Richard Ainley, an acting instructor. Tom often saw Anthony, who would come over to play with Richard's children, but always thought of him as mysterious.

Audio
Geoffrey Beevers is the main portrayer of the character in Big Finish audios. Sometimes, as in The Fourth Doctor Adventures, he's merely reprising the pre-Tremas Master seen in The Keeper of Traken. On other occasions, he has portrayed a post-Survival Master that has had the Tremas layer peeled away. Thus, in Dust Breeding and Master, he is once again the decayed version of the Delgado Master.

Additionally, Alex Macqueen portrayed the Master in the audio drama UNIT Dominion and Time's Horizon/Eyes of the Master, set at a time where the Master is rescued by the Time Lords and is set to work on their behalf.

Anagrams
During Anthony Ainley's tenure as the Master, pseudonyms made from anagrams of the actor's name were often used in the credits for the Master's disguises, such as Neil Toynay for the Portreeve in TV: Castrovalva. Tremas is itself an anagram of Master.

The tradition has continued in the BBC Wales version of the show. During series 3, the Master takes on two new identities, Professor Yana in TV: Utopia, and Mr. Harold Saxon in TV: The Sound of Drums and TV: Last of the Time Lords. Yana is an intentional acronym of 'You Are Not Alone, the final words of the Face of Boe, which led the Doctor to discover that Yana was a Time Lord.