The One (Time Lord)

The One was the main alias used by the first incarnation of a Renegade Time Lord who suffered from regenerative dissonance.

Biography
The One once worked in the Panopticon Archive, where he found information about a prototype stellar manipulator. He had a seat on the High Council, although this was explained as a result of the Council prompting him to the position when various other members were away on other business and a certain number of votes were required for particular motions to be passed. He later left Gallifrey and became a criminal.

During her meeting with the Eleven, Kiani hinted that the One had a different name before he became a criminal, but the Eleven insisted on calling him "the One".

Kiani also told the Eighth Doctor that the One had studied his story and was inspired by it. (AUDIO: The Eleven, The Satanic Mill)

Behind the scenes

 * The script of Dark Universe describes the One as a "fussy old archivist, pedantic and knowledgeable on many Gallifreyan secrets".