Tremas Master

After stealing the Trakenite body of Tremas to replace his decaying Time Lord one, the Master resumed his crusade to conquer the universe and kill the Doctor. He somewhat succeeded in the latter, as his actions at the Pharos Project resulted in the regeneration of the Fourth Doctor, and he continued to plague the Doctor afterwards.

Eventually landing on the Cheetah World, the Master became infected with the Cheetah virus, which increased his aggressive behaviour. The Master would continue to be plagued by the virus for some time until he overcame the effects, although sources rarely agreed on what became of this Master. According to one account, he was regressed back to his cadaverous form by the Warp Core. Another account suggested he was cured by Tzun nanites and regenerated after being shot by Ace. And two further accounts suggested that this incarnation was executed on Skaro by the Daleks, then possessing the body of Bruce Gerhardt.

First exploits
After he visited the Scoundrels Club to recover from changing bodies in comfort, (PROSE: Dismemberment) the Master came back to Djinn, visited Moses and admired his job. Moses told the Master he was dying, unless he could provide him with a special fluid made out of Carophil, manufactured on the planet Restovan. The Master disguised himself as the Fourth Doctor, gained access to the place where the fluid was kept and brought it to Djinn. But Moses had deceived the Master; the liquid he brought him was poison to him. He drank with no hesitation, thus releasing himself from the Master's grip. (PROSE: A Master of Disguise)

The Master 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 then went to Logopolis, where he pretended to be Tremas to gain 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 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. 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 the Doctor stopped the Master's signal to shut down the CVE that would halt the entropy wave, the Master caused him to fall off the Pharos Project's radio telescope and regenerate, allowing the Master to escape. (TV: Logopolis)

As the Fifth Doctor made his leave in the TARDIS, the Master reappeared and kidnapped Adric and held him in a hadron web to make him a part of his TARDIS. Using a projection of Adric, the Master sent the Doctor's TARDIS 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 remained trapped in Castrovalva for some time, but was able to find a way to project himself in England in the 1920s. In an attempt to capture and kill the Doctor and his companions and escape Castrovalva, the Master 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 revenge plan. (AUDIO: Smoke and Mirrors)

The Master eventually escaped from Castrovalva, (TV: Time-Flight) but in the attempt, it caused damage to the dynamorphic generators, making it difficult to continue piloting his TARDIS. (PROSE: The Quantum Archangel) He managed to travel 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 the Master 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, the Master found and acquired Kamelion, a shape-changing android that could be easily controlled by a strong mind. Managing to elude Xeraphin, the Master escaped to England in 1215. (TV: The King's Demons) Killing the French knight "Sir Gilles Estram" to assume his identity, (PROSE: Sanctuary) the Master made Kamelion impersonate John of England to prevent the signing of Magna Carta. However, the arrival of the Doctor, Tegan and Vislor Turlough caused interference with his plans. After the Doctor defeated him in, first, a sword-fight and then a mental battle of wits over the command of Kamelion, the Master fled in his TARDIS. (TV: The King's Demons)

The Game of Rassilon
When the High Council of the Time Lords discovered that the first five incarnations of the Doctor had been time scooped and taken into the Death Zone on Gallifrey, they asked the Master for help and offered him a new cycle of regenerations as a bargaining tool. He agreed and was given a copy of the Seal of the High Council by the Castellan to prove his credentials. However, the Third Doctor did not believe the Master and blamed him for their being there, taking the seal from him on the pretence that he would return the "stolen property" to the High Council.

The Master soon after encountered the Fifth Doctor, who also had trouble believing him, especially when he claimed that the Third Doctor had taken his only proof. Before he could further attempt to gain his trust, however, a group of Cybermen ambushed them, the Doctor using the Master's recall device to escape and meet with the High Council when the Master was knocked out. Upon waking up, he formed a temporary alliance with the Cybermen to guide them to the Dark Tower, although it was clear they would kill him once he was no further use. After he let the Tower's traps slaughter the Cybermen, he hinted to the First Doctor how to get past security, but then grew power-hungry at the mention of immortality, and prepared to kill the first three incarnations of the Doctor, still angry at the Third Doctor for refusing his help when he was genuinely there to lend assistance. Brigadier Lethbridge-Stewart knocked him unconscious and Sarah Jane Smith and Tegan Jovanka bound him with rope. After Borusa was encased in Rassilon's tomb, Rassilon sent the Master back to his own time, promising that "his sins [would] find their punishment in due time". (TV: The Five Doctors)

Without a body
One account stated that the Celestial Intervention Agency believed Rassilon had allowed the Master to escape Gallifrey unscathed, an act which mystified the CIA. (PROSE: CIA File Extracts)

However, according to another account, for failing to help the Doctor in the Death Zone, the Time Lords destroyed the Master's Trakenite body, reducing him to little more than a helpless phantom as they exiled him to the depths of a forest. The Master was found by his TARDIS after it managed to resist the Time Lords attempt to reprogram it, and it helped him to attain physicality in the form of a shadowy figure in dark robes. In an attempt to trap the Doctor and steal one of 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.

His plan was to force a regeneration out of the Doctor and steal this one life to revive himself using an arcane ritual involving twelve mirrors — but the Doctor was saved by Vislor Turlough, and the Master's plan was foiled yet again. Instead, the Master found himself confronting mental projections of all his past regenerations. In a prowess of will that impressed even the Doctor, the Master was able to overpower the shades of his past selves and steal a bit of life energy from each of them, allowing him to regenerate back into his Trakenite body. (PROSE: The Velvet Dark)

Damaging his body
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 boost his telepathy, the Master made contact with Kamelion once more, directing him to use the Doctor's TARDIS to land on 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 apparently burn him to death. (TV: Planet of Fire) However, the Numismaton Gas increased the power of the Source of Traken still remaining in the Master's body, enabling the Master to survive. (PROSE: The Quantum Archangel) Horrifically burned, the Master went in search of the Fountain of Youth to restore himself. (PROSE: A Town Called Eternity)

Interfering with regeneration
Using his link to Kamelion, the Master attempted to psychically interfere with the Doctor's fifth regeneration, (AUDIO: Winter) urging the Doctor to die from the spectrox toxaemia poisoning in the TARDIS, (TV: The Caves of Androzani) but was foiled by Nyssa. (AUDIO: Winter)

Interfering in history
The Master allied with his old Academy classmate, the First Rani, in Killingworth against the Sixth Doctor and Peri Brown; the Master hoped to hasten the advancement of Earth's technology for his own nefarious reasons, while the Rani wanted the brain chemical that induced sleep in humans. The Doctor trapped the Master and the Rani in the Rani's TARDIS, which the Doctor had sabotaged, with the time spillage putting 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, freeing himself while leaving the Rani to drift aimlessly through the vortex. (PROSE: State of Change) The Doctor sent a message to Gallifrey warning them of the Master and Rani's survival, but the Celestial Intervention Agency did not believe it, alleging that the "unstable mind" of the Doctor's new incarnation must have made the whole thing up. (PROSE: CIA File Extracts)

Forging alliances
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. Learning that the Valeyard was an "amalgamation of the darker side of [the Doctor's] nature", the Master decided that the Valeyard was a bigger threat and rescued the Doctor by supplying the Doctor with witnesses in the form of Melanie Bush and Sabalom Glitz, and revealing himself to the court as a surprise witness. Using Glitz as a tool, the Master tried to steal secrets from the Matrix, but was beaten by the Valeyard, and imprisoned in the Matrix by a limbo atrophier with Glitz. (TV: The Ultimate Foe)

One account claimed the Time Lords released the Master and Glitz 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)

According to another account, the Master was exiled to the planet Alexis by the Time Lords. In his exile, the Master observed the life forms of the planet, the Mogellans, and saw how they were all connected in one great environment, and how they used special crystals to communicate. When a Kotturuh woman arrived on the planet, the Master pretended to intercede for the Mogellans' salvation, and they gave him one of the crystals as a a token of good faith. The crystal, however, revealed them that the Master was lying in order to exploit the crystals in the future, and they allowed the Kotturuh to end their lives to stop him. (AUDIO: Lesser Evils)

The Master was greeted by a female incarnation of himself known as "Missy", who had developed a plan to form a band to hypnotise viewers of Battle of the Bands Beyond the Stars. , and  all joined in the plan, and the team spent "decades" practising. (COMIC: The Five Masters) He played the bass guitar. After unveiling their presence to the Twelfth Doctor and Clara Oswald, (COMIC: The Abominable Showmen) the Masters prepared for their performance. However, the "Tremas" Master began to fight with Missy over the possession of her device, believing that he alone could hold the universe in his grasp. The other incarnations joined in the fight, and the five were eventually disqualified, seemingly destroying them. (COMIC: The Five Masters)

Haunted by the past
After escaping from an unsuccessful alliance with the Krotons, the Master was attacked by the Chronovores looking for revenge for his torture of Kronos, and discovered that the last remnants of the Source of Traken were fading, reducing him to his previous cadaverous form. 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 on 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 and the Sixth 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 Trakenite body. (PROSE: The Quantum Archangel)

Distancing himself from the Doctor
At some point, the Master discovered the Parallel Sect, where he possessed the body of Keith Potter, wanting to dominate the dimensional nexus. He found the Valeyard, and encountered the Sixth Doctor and Constance Clarke. After the Doctor defeated him, the Master was confronted by the Valeyard, who threatened him, forcing the Master to both leave the nexus and never return and to leave the Doctor alone, as the Valeyard had a plan to deal with him. (AUDIO: The End of the Line)

Alongside and, the Master reacted with shock when , a female incarnation from their future, presented the three Masters with her infant child. (PROSE: Winning)

Deadlier campaigns
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. (TV: Survival)

The Master used the Cheetah People to ambush the Seventh Doctor and Ace by kidnapping some friends of the Doctor, but he was entombed in an avalanche caused by the Doctor when he came to save his friends. (PROSE: Dr. Seventh)

As exposure to the planet began changing the Master into a Cheetah Person, he sent the kitlings to Ace's home in the London suburb of Perivale to hunt for human recruits. Eventually, he found a pliable young man called Midge and used him to escape. Using Midge as his "hunting dog", the Master recruited a gang of Perivale youths to defeat the 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 the Cheetah Planet
What happened to the Master after the Cheetah Planet was a topic of great controversy. It was universally thought that, some time after escaping the planet, some version of the Master was put on trial by the Daleks and exterminated. (TV: Doctor Who) However, the circumstances of when this occurred, and what incarnation was involved, were not clear, (PROSE: Stop the Pigeon, Prime Time, The Eight Doctors; AUDIO: Dust Breeding) Missy herself admitted that her memory of what happened to the Master after being left stranded on Cheetah World was vague at best, to the extent that she was unsure said event had even taken place. (PROSE: Meet Missy!)

Tzun Conspiracy
According to one source, the Master became trapped on Earth without his TARDIS in the year 1957 after escaping the destruction of the Cheetah Planet by using a kitling named Shadow to transmigrate just as the planet exploded. The Master interrupted the 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 was meant to restore the Master to being a "full" Time Lord, giving him a new regenerative cycle and curing the Cheetah virus.

Shortly after being restored to his full Time Lord heritage, he was shot in the back by Ace to avenge his murder of Joe Manco, 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 Doctor in a nuclear warhead, the Master fled. (PROSE: First Frontier)

Survival
By another account, directly after the Cheetah Planet plot, the Master appeared in the Doctor's TARDIS and damaged it, intending to force the Doctor ad Ace to face a new scheme. (PROSE: How did this creep get in here, Professor?) Several further accounts seemed to depict the Tremas paster post-Cheetah World.

According to another account, the Master, still in Tremas's body, attempted to stave off the effects of the Cheetah virus by posing as a "Dr Howard Chithros" and draining the life from his elderly patients. The Seventh Doctor discovered the scheme and the nursing home was destroyed in the ensuing battle between the two Time Lords. The Master escaped in the confusion, leaving the Doctor to pick up the pieces. (PROSE: Stop the Pigeon)

The Master attempted to gain a new body from a legendary race known as the Fleshsmiths, claiming that the Cheetah virus would kill his Trakenite body within a year, but his plan was stopped by the Doctor, who ejected the new body from the Fleshsmith vessel into space. (PROSE: Prime Time)

No longer affected by the Cheetah virus, and wanting to find a way to survive beyond his final regeneration, the Master tried to steal the body of a mouse-turned-boy named Callum, but his plan was foiled by the Doctor. (PROSE: Omegamorphosis)

After meeting Adam Mitchell, a companion who had betrayed the Ninth Doctor, the Master began working to help him take revenge on their common enemy. (COMIC: The Choice) Together, they set up an asylum in 7214 with Autons as staff as a trap for the Sixth 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: Façades)

Using a group of Aeroliths to further his alliance, the Master syphoned their life force, to transmit to Adam, using a Gulwort. However, when they were freed by the Seventh Doctor, they chased after him. (COMIC: Cat and Mouse) After being tortured by the Aeroliths, the Master escaped, and, reunited with Adam, encountering the Eleventh Doctor. Discouraging Adam from listening to the Doctor, the Master watched in satisfaction as Adam prepared to kill the captured companions, (COMIC: The Choice) but was prevented when the Doctor summoned his earlier incarnations and revealed that he had arranged for Frobisher to infiltrate the plan by allowing himself to be captured while posing as Peri.

The Master and Adam released an Auton army, but the Doctors were able to keep them occupied long enough for Frobisher to release the other companions as reinforcements. However, unbeknownst to Adam, the Master planned to destroy reality itself, using the merged TARDIS that brought the Doctors there to channel chronon energy in a massive backlash that would unmake history. Convinced by the Doctors, Adam stunned him, but the Master stabbed him with a hidden knife. The injured Adam managed to foil the Master's plan but died in the attempt. The Master, still pleased by his role within all the chaos, teleported away. (COMIC: Endgame)

Tremas Destroyed
According to one account, the Tremas 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, which stripped his Trakenite body from him and reduced him to his previous decaying form. (AUDIO: Dust Breeding)

Before the Daleks
Two separate accounts suggested that the version of the Master executed on Skaro was the Tremas Master.

In the first, a visibly older Master with greying hair used the planet Siralos's psychic energy to capture the first seven incarnations of the Doctor and put them into a void called the Determinant. However, the Graak opposed him, and the Master engaged in a battle of wits with the creature. The Master captured several other species to battle the Graak, including the Cybermen, the Sea Devils, and the Daleks. The Graak successfully freed the Doctors.

Afterwards, the Master was captured by one of the species he had used in his scheme, with him suggesting to the Doctor that "[the Doctor] knew what they [would] do to him" for his crimes against them (GAME: Destiny of the Doctors) seemingly leading to the Master being executed by the Daleks. (TV: Doctor Who)

Another account showed that the Master immediately surrendered himself to the Daleks after obtaining a Deathworm Morphant from the Morgs, not long after his experiences on the Cheetah Planet. (PROSE: The Eight Doctors) The Master made one final request, for the Doctor to return his remains to Gallifrey after his execution. Using the Deathworm Morphant, the Master instead took the Doctor's TARDIS to 1999 San Francisco, where he possessed the body of an ambulance driver. (TV: Doctor Who)

Post-mortem
Professor Yana heard the laughter of the Tremas Master as well as the voice of a previous incarnation whilst the War Master ordered his human disguise to open the fob watch containing him. (TV: Utopia)

Parallel universes
In an alternative universe created by the Quantum Archangel, the Master joined the Time Lords to fight in the War. However, he began aiding the Daleks by giving them temporal manipulation technology. The Sixth Doctor, who was Lord President Admiral of Gallifrey, activated the Armageddon Sapphire and destroyed the universe rather than letting the Enemy win. (PROSE: The Quantum Archangel)

In a different alternative universe created by the Archangel, 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
After possessing Tremas's body, the Master became a more flamboyantly evil, bombastic and sophisticated individual, (TV: Logopolis, Castrovalva, Time-Flight, The King's Demons, The Five Doctors, The Ultimate Foe) who only put trust in himself. (TV: The Mark of the Rani) He was prone to laughing maniacally and reciting lengthy and verbose speeches, accompanied by melodramatic gestures and poses. (TV: Time-Flight, The Five Doctors, The Mark of the Rani) The Seventh Doctor even recalled the "Tremas" Master as having "a taste for melodrama." (AUDIO: The Two Masters)

The "Tremas" Master was unwilling to share any form of power with others, often betraying those he worked with to accomplish his own goals, (TV: Logopolis, The Five Doctors, The Ultimate Foe, Survival) even when working with his other incarnations. (COMIC: The Five Masters)

While in Tremas's body, the Master became devoted to killing the Doctor, often employing elaborate gambits and strategies to this end. (TV: Castrovalva, The Mark of the Rani; GAME: Destiny of the Doctors) However, he mused that a cosmos without the Doctor "scarcely [bore] thinking about", and was willing to join forces with the Doctor if he viewed it as beneficial to himself. (TV: Logopolis, The Five Doctors, The Ultimate Foe)

He showed a genuine disregard for life and was often uninterested in how many people died at his hands, (TV: Logopolis, Castrovalva, The King's Demons, Survival) and had a particular fondness for the Tissue Compression Eliminator. (TV: Logopolis, Time-Flight, Planet of Fire, The Mark of the Rani) However, he showed an unusual level of moral standards when he apologised to Peri Brown for involving her in a battle that was originally supposed to be between him and the Sixth Doctor, and was genuinely horrified when the Rani's contraption turned Luke Ward into a tree, although the Doctor considered it an example of how warped and callous the Master was if he thought that establishing that Luke's death was an accident was any kind of excuse. (TV: The Mark of the Rani) He was also horrified upon witnessing the Kotturuh judgement on Alexis. (AUDIO: Lesser Evils)

The Master was delighted and satisfied when Lord President Borusa addressed him as "one of the most evil and corrupt beings [the] Time Lord race [had] ever produced", but was surprised and outraged when his attempts to convince the Third Doctor of his sincerity was ridiculed and spurned. (TV: The Five Doctors) He also thanked Mel Bush when she remarked on how "evil" he was. (TV: The Ultimate Foe) When the Seventh Doctor questioned the Master's decision to "act the villain", the Master stated he was "famed for [the] role", and claimed to enjoy the "typecasting". (COMIC: Crossing the Rubicon)

After he was infected by the Cheetah virus, the Master became more calm and calculating. However, as the virus took its toll, he became more animalistic and sadistic, taking satisfaction in murdering Karra and attempting to hit the Seventh Doctor's head with a club during their fight. (TV: Survival)

The "Tremas" Master had various opinions of the first seven incarnations of the Doctor. He referred to the First Doctor as a "bore", the Second Doctor as an "incapable comedian", the Third Doctor as a "worthy foe", the Fourth Doctor as "the bohemian, [and] the wanderer", believed that the Fifth Doctor was "the nice one full of charm, innocence, and naiveté", described the Sixth Doctor as "the blustering one with the stupid coat", and that the Seventh Doctor was "too busy setting traps" to realise the ones "set for him". (GAME: Destiny of the Doctors)

described her "Tremas" incarnation as being "the Sneaky One". (PROSE: Meet Missy!)

After he was shot in the back by Ace to avenge his murder of Joe Manco, the Master withered in extreme pain that he tried to fight while complaining about how close he was to victory. Clawing at his wound and grasping his head, the Master regenerated while cowering from the pain in his TARDIS, begging to be "free". (PROSE: First Frontier)

Skills
Unlike his predecessor, the "Tremas" Master seemed unable to use natural hypnotism, instead using an Electro-muscular constrictor to enslave Nyssa, (TV: Logopolis) causing misdirection to discredit the Fifth Doctor at Fitzwilliam Castle, (TV: The King's Demons) and took control of Luke Ward by combining hypnotic suggestion via a crystal necklace with the Rani's mind parasites. (TV: The Mark of the Rani) When his attempts to hypnotise Sabalom Glitz with a swinging silver pendant failed due to Glitz's mind being occupied with calculating the wealth of the pendant, the Master resorted to offering Glitz a chest full of jewellery to ensure his cooperation. (TV: The Ultimate Foe)

The "Tremas" Master was able to accurately predict the Doctor's movements, implementing multiple ways to kill him and manoeuvring him into them with relative ease. (TV: Logopolis, Castrovalva, The Ultimate Foe) even believed that his plans were so overcomplicated that if he walked in a straight line he would get dizzy. (TV: The Mark of the Rani) Unlike his other renditions, the "Tremas" Master was able to improvise when things turned awry. (TV: Logopolis, The Five Doctors, Survival)

Appearance
After the Master used the power of the Source to steal Tremas's body, the Trakenite's body was also rejuvenated, with his grey hair becoming a dark brown, and his white bushy beard turning into a black goatee beard. (TV: The Keeper of Traken) The Fifth Doctor had a low opinion on the beard, calling it "rubbish" when he met his tenth incarnation. (TV: Time Crash)

After the Master stole his body, Tremas's robes inexplicably changed into a black velveteen high collared tunic with puffed sleeves and long tails, (TV: The Keeper of Traken) black trousers, dark leather boots, and black velvet gloves. (TV: Logopolis) The Master would also utilise a cloak with a large collar. (TV: The Five Doctors)

While stranded on Cheetah World, the Master opted to change his usual attire for a black collarless silk jacket, a navy blue shirt with an ivory collar, a midnight blue bow tie, black trousers and shoes, a silver waistcoat (with the collar coming out over the collarless jacket), and a belt with a dragon-shaped buckle. (TV: Survival)

In an account that depicted the "Tremas" Master with greying hair, he wore a red velvet jacket with a popped collar, a silver waistcoat with a black turtleneck, and a pair of dark trousers, with leather gloves and shoes, with various rings decorating his gloves. Completing the ensemble was a black cloak with a huge collar and white lining, (GAME: Destiny of the Doctors) which the Master had also worn during his alliance with Adam Mitchell. (COMIC: Cat and Mouse)

While combating the Graak in the Determinant, the Master adopted many costume changes to suit the situation he found himself in; wearing an a conductor hat with an "M"-insignia at a platform station, a bowler hat while on a train taunting the Graak, a Dalek Trooper helmet while commanding a rocket launcher, and a plastic crown at a medieval themed festival. (GAME: Destiny of the Doctors)

Other references
Shaw Taylor acknowledged the Tremas Master as the latest of the Master's three known "regenerations", following and. Shaw believed the Master to be 700 years old. (TV: Police 5: The Master)

Shortly after his initial confrontation with, the Tenth Doctor, whilst in a Multi-Doctor Event with the Fifth Doctor, acknowledged this incarnation's frequent encounters with the Master before disclosing that he had "just shown up again". When the earlier Doctor asked if the Master still had "that rubbish beard", the Tenth Doctor answered that he had "no beard this time. Well, a wife." (TV: Time Crash)

As recorded in the Masterplan Journal left behind by, had carved the image of "Beardy Two" into Mount Rushmore during the Year That Never Was along with his then current self,  and , observing that there was no room for. (PROSE: The Secret Diary of the Master)

Whilst trapped in the Matrix by the Spy Master, the Thirteenth Doctor remembered, amongst many others, the Tremas Master in order to break out of the computer system. (TV: The Timeless Children, TV: Logopolis)

During the Master's Dalek Plan, the Spy Master confronted Tegan Jovanka and Ace, both companions of the Doctor who knew the Master in his Tremas form. The Master taunted Tegan by asking her if she kept her Aunt Vanessa in a little doll's house, whilst Ace recalled that he was "half cat" the last time she saw him, with the Master sheepishly retorting that "a man's allowed to experiment." (TV: The Power of the Doctor)

Ainley's Master

 * Anthony Ainley wanted to play his incarnation of the Master as cold and calculating but, with the exception of his final televised appearance, he instead portrayed the character as a pastiche of original actor Roger Delgado.
 * During Anthony Ainley's tenure as the Master, pseudonyms made from anagrams of "Tony Ainley" were often used in the credits — both on-screen and in Radio Times — for the Master's disguises, such as Neil Toynay for the Portreeve in Castrovalva. This practice was later adopted by Mark Gatiss, who played the Unbound Master in Sympathy for the Devil under the anagrammatic pseudonym "Sam Kisgart".
 * Another, craftier pseudonym was used in Radio Times for The King's Demons, when Sir Gilles was listed as being played by "James Stoker" — an anagram of "Master's Joke". This name was confirmed as an alias used by the Master in-universe at some point before the events of Planet of Fire in the novel CIA File Extracts.
 * Anthony Ainley notably contributed to the charity single Doctor in Distress. Following Nicholas Courtney's line "there was a Brigadier and a Master", Ainley gave his Master's iconic laugh before adding "and a canine computer".
 * Amongst the names used by the Master in the parallel universe of Exile is Tony, a reference to Anthony Ainley.
 * A composite of Anthony Ainley as the Master and George Pravda as Spandrell was used to provide the likeness of played by James Dreyfus on the cover artwork of Solo, the anthology which contained his appearance in Blood of the Time Lords.

Cancelled appearances

 * In the original outline to K9 and Company, it would have been eventually revealed that Sarah Jane Smith's K9 Mark III was actually sent by and under the control of the Master, but this element never made it to the screen.
 * The who fought the Fifth and Sixth Doctors in the Doctor Who Annuals came about as a result of World Distributors having failed to secure the rights to the likeness of either Roger Delgado or Anthony Ainley. The first story to use him had likely been written on the assumption that the Master was the Anthony Ainley version and gave no explanation for the Master's manifestly different appearance, leaving this incarnation's place in the Master's overall timeline up to reader interpretation (although his second appearance in The Fellowship of Quan more explicitly established in-text that he was not the face Peri Brown had previously encountered — i.e. Ainley).
 * Doctor Who Pinball: Time Streams featured an uncredited actor as the Master, with a vocal impression based upon the performance of Anthony Ainley. Though it had originally been planned to have Ainley record lines for the pinball game, but due to confusion and slow passing of information from Bill Pfutzenreuter through various individuals to Ainley and vice versa, this did not come to pass. It was later discovered that Ainley had soon after sent a letter to one individual involved in the chain of communication, explaining that his UK agents had not been helpful in the matter and that he had not been able to properly consider the project.
 * Oddly, despite the replacement performer deriving their performance from Ainley, the Master is credited as being the . The board drawing still has the clothes of the Ainley incarnation.
 * Big Finish Productions had invited Anthony Ainley to reprise his role of the Master in Dust Breeding, but were unable to reach a suitable deal with him. The Tremas Master was therefore written out by having the Warp Core strip the Master of his previous body, leaving behind his previous emaciated form, therefore allowing Geoffrey Beevers to take over the role.
 * Anthony Ainley was planned to star as Koschei, a young, pre-The Dark Path version of the Master in the ultimately unproduced BBV Productions audio series of the same name. The pre-corruption Koschei would have been characterised as an investigator of strange phenomena, in a style similar to Sapphire and Steel or . However, Ainley died while David A. McIntee was still working on the synopsis for what would have been the first story in the series, scuppering the plans. (REF: Downtime – The Lost Years of Doctor Who)

Other possible appearances

 * An unidentified incarnation of the Master features in Enjoy the Game, a short tie-in to the Escape from the Master quiz game. The header to the game itself included an image of Anthony Ainley's Master on a monitor, but a similar image depicting, instead, appeared on the Doctor Who website's home page on the widget leading one to the quiz and the short story. Thus, it appears that even the BBC had no definitive pronouncement on the identity of the story's Master.
 * Voiced by David Garfield, Professor Stream in The Hollows of Time was originally intended to be a pseudonym of the "Tremas" Master, but copyright restrictions prevented them from making this explicit in the story. "Stream", like "Tremas", is an anagram of "Master". The story is listed as a Master one on the Big Finish website.

Invalid sources

 * The original second volume of The Doctor Who Programme Guide (1981) stated that had used Tremas's body for his "thirteenth regeneration", implicitly designating the resulting "Tremas Master" as the Master's fourteenth incarnation. This would be contradicted in The Five Doctors, in which the Master admits to the Third Doctor that his new appearance is "not exactly" a regeneration.
 * The behind the scenes book A Celebration (1983) had a feature entitled The Two Regenerations of the Master, also referring to The Two Faces of the Master, namely the Delgado Master and the Ainley Master. From a production standpoint, Delgado was identified as the "first Master", whilst Ainley was designated as both the "second incarnation" and the "second regeneration" of the Master, though the feature does also acknowledge the interim "twelfth and final regeneration" portrayed by Peter Pratt and Geoffrey Beevers.
 * Anthony Ainley made an appearance as the Master in A Call from the Master, broadcast on the children's phone-in show Saturday Superstore in 1985. Serving as a tie-in with The Mark of the Rani, it saw the Sixth Doctor and Peri Brown receiving a phone call from the Master and therefore being alerted to his survival following the events of Planet of Fire.

FASA
The Doctor Who Role Playing Game by FASA, which admits to taking liberties with the source material in its opening pages, gives a rundown of the Master's incarnations in "The Master" supplement book, which was similar to (but not entirely consistent with) the in-universe biography given for the Master in FASA's own CIA File Extracts.

The Master assumed what was identified as his fourteenth incarnation when his possessed the body of Tremas. This new form was not unlike his but appeared younger with dark brown hair. An attractive man who appeared middle-aged when in reality he was over 900 years old, the Master had an average height and build and was distinguished by his satanic beard and grey eyes whilst wearing a black tunic and gloves. As this body was not Gallifreyan, the Master lacked the natural ability to regenerate, however, exposure to the Numismaton Gas of the planet Sarn gave the Master considerable powers which included the ability to re-trigger a life cycle of regenerations in his stolen body. Escaping his fiery death, the Master regenerated into a fifteenth incarnation with a form identical to that of his previous incarnation.