Vansell

Vansell (full name Vansellostophossius) was Coordinator of the Celestial Intervention Agency. He was a determined person who did his utmost to keep Gallifrey in its position of power, and to maintain the Web of Time.

Biography
The Doctor knew him at the Academy. The Doctor (supposedly) called Vansell by the nickname of 'Nosebung'. (BFA: Neverland)

Vansell, angered at the fact that he believed that the Doctor had let the Nestene Consciousness escape destruction by the Time Lords, set up a trial for him on Space Station Zenobia (PDA: Synthespians™)

Vansell led an expedition into the world of Anti-Time to find what he believed to be the body of the Time Lord's revered founder, Rassilon. He became possessed by anti-time energy, and attempted a coup. Afer overcoming the possession by the anti-time energy, he was killed when he assisting Lady President Romana. He was trapped within the Time Station's temporal reactors and was vaporised. (BFA: Neverland)

Alternative versions
In an altered timeline he attempted to kill the Doctor on multiple occasions. (DW: The Sirens of Time)