- You may be looking for Goth.
Pandad IV, (PROSE: The Legacy of Gallifrey) also referred to as Pardar V in one internal CIA memo, (PROSE: CIA File Extracts) led Gallifrey as First Time Lord (TV: The War Games, PROSE: Doctor Who and the Doomsday Weapon) and President of the Council. (TV: The Three Doctors)
The 406th sitting President, (PROSE: A Brief History of Time Lords) he lived through several incarnations while in office (PROSE: The Legacy of Gallifrey et al.) despite his tenure ultimately being far shorter than nine hundred years. (TV: The Deadly Assassin) The entirety of the Third Doctor's exile on Earth occurred during his time as President and he eventually lifted it after the First Omega Crisis on the advice of Chancellor Socra. (PROSE: The Legacy of Gallifrey)
Struck by tragedy when the First Rani's experiments with giant mice caused him to regenerate, along with the deaths of Socra and his cat, (TV: The Mark of the Rani, PROSE: The Legacy of Gallifrey) his new administration proved to be short-lived when he was assassinated by his new Chancellor, Goth, who had been conspiring with the intent of ascending to the highest office after meeting the Decayed Master, an act that gave way to the most dangerous crisis in Time Lord history. (TV: The Deadly Assassin)
Beginnings as President
Before she was recruited by the Celestial Intervention Agency, Lady Serena had been studying the records of the most recent presidential election in the Capitol Library, attempting to work out the truth of what actually happened and where it lay between the lines of the official accounts. (PROSE: World Game)
The Doctor's trial
Although one account suggested the Time Lord who led the tribunal summoned by the Second Doctor to put an end to the War Games was Goth, (PROSE: Future Imperfect) many agreed that it was the then-Lord President, (PROSE: The Three Doctors) Pandad IV. (PROSE: The Legacy of Gallifrey)
The President first presided over the trial of the War Lord. The tribunal found him guilty and sentenced him to dematerialisation as if he had never existed. (TV: The War Games) He then lead the trial of the Second Doctor for violating the non-interference policy that resulted in his exile to Earth and forced regeneration into his third incarnation. (TV: The War Games; PROSE: Doctor Who and the Auton Invasion, The Three Doctors) During the Doctor's trial, he revealed that Jamie McCrimmon and Zoe Heriot would be sent back to their own times with no memories of their travels. He also pronounced the Doctor's sentence, but, after he rejected the choices offered to him for his next incarnation's appearance, the President bluntly told the Doctor that the choice would be made for him before enacting his punishment. (TV: The War Games)
According to one account, however, this version of events was a fabrication, the minutes of the trial having been substantially re-edited for the public record. The true record was eventually released under the provisions of the Gallifreyan Freedom of Information Act. The President of the Court told the Doctor that the theft of a TARDIS was a relatively minor offence that could be pardoned, but told the Doctor that the Court's hands were tied on the second matter. Instead of telling the Doctor he would be exiled, the President instead told him that his prolonged and temporal interference drew attention to the the very existence of the Time Lords and that the safety of their race had lain in silence and secrecy for many years. He went to surmise that offences of this nature were capital crimes before reluctantly sentencing him to death. The charges were commuted to a period of exile after the Doctor struck a deal with Sardon and agreed to work for the CIA. (PROSE: World Game)
Trouble with the Master
After the Master arrived on Earth, seeking revenge against the Doctor for past deeds, Socra persuaded Pandad to send a member of the High Council to warn the Third Doctor. After this, the Celestial Intervention Agency made constant use of him as a free agent. The Doctor resented this but knew that it was only a matter of time before the CIA, probably through Socra, convinced Pandad to release him from his exile. (PROSE: The Legacy of Gallifrey)
Having regenerated, along with Second Time Lord Adelphi and Third Time Lord Socra, (PROSE: Doctor Who and the Doomsday Weapon, The Legacy of Gallifrey) Pandad was alerted that a report on the Doomsday Weapon had gone missing from the Time Lords' files and that only the Master could have taken it. Pandad suggested using the Doctor to deal with the problem and, after his advisors cast doubt over the likelihood of his cooperation, he told them that they would restore his freedom for as long as it served their purpose. They sent the Doctor's TARDIS, containing the Doctor and Jo Grant, to the planet Uxarieus in the year 2472. (TV: Colony in Space)
The Omega crisis
During the First Omega Crisis, a regenerated Pandad decided to use the last of the Time Lords' power to summon the Doctor's first two incarnations to help the Third Doctor to resolve the crisis. His decision to break the Laws of Time met with criticism from High Chancellor Socra, but Pandad had faith in his gamble since the Time Lords didn't have any better solution. After his gamble proved successful, Pandad rescinded the Third Doctor's exile on Earth and restored his ability to travel through time and space, (TV: The Three Doctors) having been advised to do so by Socra, who, when Pandad demanded an explanation, revealed to him the existence of the Celestial Intervention Agency. Pandad decided to keep it secret from the population, despite the CIA's offer to go public, feeling that it might risk lessening the Gallifreyan people's faith in the Presidency. (PROSE: The Legacy of Gallifrey)
Dealings with the Fourth Doctor
On Jewel, Pandad was alerted when the time thread of the Fourth Doctor's TARDIS was lost. He ordered an inter-galactic time search to find it. Shazar went to Jewel to convince the Time Lords that the Doctor was in league with the Daleks. Pandad pretended to accept the lie and allowed Shazar to return to his Dalek masters with cirenium to fuel the TARDIS' time circuits. In fact, cirenium could destroy timeships and Pandad had fooled Shazar into aiding in the destruction of the fleet of TARDISes the Daleks were building. As punishment, the Time Lords shrunk Shazar and placed him in a jar, with the Doctor and Sarah Jane Smith leaving him on a primitive planet so that he could do no harm. (COMIC: Return of the Daleks)
After a man resembling the Fourth Doctor was hypnotised by the Vatheks and left terror in his wake, a Junior Time Lord demanded that Pandad summon the Doctor to a Court of Enquiry to explain his actions, although Pandad believed there was no need for explanation, as they all knew the penalty for such crimes. Although the Doctor denied the allegations, he was found by Pandad to have abused his position as a Time Lord and was sentenced to death. However, the Junior Time Lord instead suggested a sentence of one million years in suspended animation. When the Doctor's double remained in operation while the Doctor was incarcerated, the Time Lords realised their mistake and the Junior Time Lord revealed he had only imprisoned him in his TARDIS because he suspected the Doctor's innocence. Now enlightened of the facts, the Doctor was ordered by Pandad to punish the Vahteks and the imposter accordingly for daring to outwit them. He sentenced the Vahteks to two million years of suspended animation and unhypnotised the imposter, returning him to Earth with no memory of his recent exploits. (COMIC: Double Trouble)
President Pandad IV once fell victim an an experiment conducted by the First Rani, which resulted in some of her lab mice growing to an enormous size. The mice then ate Socra and Pandad's pet cat, and bit the President himself, triggering a regeneration. (PROSE: The Legacy of Gallifrey) The Rani exiled herself and became a renegade as a result of the incident. (TV: The Mark of the Rani) This ended the tradition of Lord Presidents possessing intelligent cats for pets and advisors, a tradition which had begun with Rassilon himself and would not be brought back until Flavia (PROSE: The Legacy of Gallifrey) became Acting President after the Fifth Doctor ran off on the Time Lords. (TV: The Five Doctors) After this tragedy, an irate Pandad appointed Councillor Goth as his new Chancellor, a decision he regretted to his dying day. He never found himself another cat.
Thirty years later, (PROSE: The Legacy of Gallifrey) Pandad decided to resign from office. Days before his tenure was due to end, Pandad informed Goth that he would not be his successor because he was too greedy for power (PROSE: Legacy of the Daleks) and because of the fact that it was seen as improper for the Chancellor to become President at the time. Instead, he intended to offer the position to Cardinal Borusa. (PROSE: The Legacy of Gallifrey) In or some time after Gallifreyan Year 6241.1, (AUDIO: Neverland) Presidential Resignation Day finally came, at which Pandad was to name his successor and read his resignation honours list, which contained some names that he believed would be found "surprising". Before being able to name his successor, Pandad was assassinated by Goth from close-range with a staser. (TV: The Deadly Assassin)
Shortly after his death, Goth described Pandad to Borusa as "wise and beloved" (TV: The Deadly Assassin) but had previously thought of him as an "arrogant" and "senile old fool" when alone. (PROSE: Legacy of the Daleks)
Pandad's sudden death caused a constitutional crisis. Goth ordered that immediate elections were to take place and initially used the Fourth Doctor as a scapegoat for the crime, putting him on trial with the intention of administering his death sentence before a new President was invested. However, the Doctor used Article 17 as a guarantee of liberty to escape this fate. Goth was eventually uncovered as the true assassin, working with the Decayed Master, who left Goth for dead. The crisis revolving around Pandad's successor persisted, however, as the Doctor's invocation of Article 17 meant that he was President-elect, which left Gallifrey without a leader after his departure from the planet. (TV: The Deadly Assassin)
The Doctor eventually returned to Gallifrey to be officially invested as President and found that Borusa had "illegal[ly]" been appointed Chancellor (TV: The Invasion of Time) and Acting President. The Doctor either resigned the position shortly after his inauguration, which allowed Borusa to be formally invested as President (PROSE: A Brief History of Time Lords) or failed to do so (PROSE: Doctor Who and the Krikkitmen) with his position made official at some point thereafter. (TV: Arc of Infinity)
The fact that Borusa had overseen the defeat of the Master after Pandad's assassination was among the reasons (PROSE: The Legacy of Gallifrey) why he thought himself worthy of seeking immortality to become President Eternal. Ultimately, this quest brought an end to Borusa's tenure as President. (TV: The Five Doctors)
The narrative engineered by Borusa for the public record stated that "the Master arrived on Gallifrey to assassinate the President, [but] Goth tracked him down and killed him, unfortunately perishing himself in the exchange of fire". (TV: The Deadly Assassin) The Fifth Doctor later discovered that his fourth incarnation's stint as Pandad's successor had been struck from the record. (AUDIO: Time in Office) Indeed, the official version of events kept in the Bureau of Ancient Records held that Borusa was Pandad's immediate successor and that, after his death, he became Chancellor and Acting President "by popular acclaim" until he could be confirmed as President by election. (PROSE: A Brief History of Time Lords)
Behind the scenes
The novelisation of The Three Doctors stated that the President in that story was also Bernard Horsfall's character, the First Time Lord, in The War Games, presumably in a prior regeneration. Doctor Who and the Doomsday Weapon seemed to support this version of events by establishing First Time Lord as a rank synonymous with Lord President.
The matter was confused somewhat when The Deadly Assassin was first broadcast after these two stories were published featuring Horsfall as Chancellor Goth. Common theory stated that Horsfall's two Time Lord characters were one and the same which ignored the previous revelation, eventually being written into a valid source by Gary Russell in the 1985 short story The Legacy of Gallifrey.