Minister of Chance

The Minister of Chance was a Time Lord.

He thwarted General Tannis' plans to infect the planet Alnelan with a deadly plague, but the his female assistant "wandered off" on the planet.

Following his defeat Tannis agreed to the Treaty of Karselai and signed away any rights to alien planets. Despite this, the Canisian military, led by Tannis, brutally conquered the Santine Republic, confining the leading members of the Republic to a prison camp. The Minister, who was able to transfer a virus to a Canisian computer via speech, took the place of a version of the Doctor in seeding a rebellion on Santiny while the Doctor investigated the deaths of two Time Lords on Earth. Tannis was also working towards wiping out the last members of the Fraction and by massacring the Santine prisoners he provoked the Minister into breaking the rules about non-interference and destroy the fleet, forcing the Doctor to confront the Minister and revoke his TARDIS. (NOTVALID: Death Comes to Time)

Beyond Death Comes to Time
In Dan Freedman's pitch for a continuation of the Death Comes to Time storyline, the Minister of Chance would have taken up the Doctor's mantle out of guilt. Though this series was not commissioned by the BBC, Freedman later crowdfunded it as the Minister of Chance audio series, where the character had regenerated into an incarnation played by Julian Wadham; Sylvester McCoy and Paul McGann also appeared in the series, though not as their Doctor Who characters. The audio series was later novelised by Freedman for Arcbeatle Press.

Appearances in valid sources
In addition to the material detailed above that continued directly from the atypical Doctor Who universe depicted in Death Comes to Time, the character has also been referenced in media considered valid by our Wiki on multiple occasions.

In the novel The Tomorrow Windows, the Eighth Doctor saw a man with a bent nose in one of the Tomorrow Windows. This character later appeared holding a pair of dice in in the novel The Gallifrey Chronicles as one of the four surviving elementals; in Lance Parkin's AHistory, he confirmed that this was a reference to the Minister of Chance. Both The Tomorrow Windows and The Gallifrey Chronicles featured other references to Death Comes to Time by mentioning Anima Persis and Tannis, respectively. The man with the broken nose and the dice, depicted with Fry's likeness (though his face was partially shrouded in shadow), also made a visual cameo in Miranda.

The Big Finish audio story The Same Face featured a renegade Time Lord going by the name of "the Minister", stated to choose a different topic to be Minister of with every regeneration. The story explained that her ten first incarnations were identical due to a mental block, from which the Doctor released her. As she begins to regenerate into the first of her incarnations not to share the titular "same face", one of her assistants quips that she should call herself "the Minister of Luck" next time. She confirms that she will continue to call herself the Minister in her next life, and pledges to try to make the world a better place, matching Stephen Fry's Minister's idealistic interventionism in Death Comes to Time. Notably, The Same Face also established the Minister of War, a figure mentioned offhand in Before the Flood, as one of the earlier incarnations of the Minister.