Kelner

Kelner served as Castellan of Gallifrey at the time that the Fourth Doctor returned to Gallifrey to claim the office of Lord President, when the planet was invaded by the Vardans and later the Sontarans. The Fourth Doctor described him as a "jumped-up guard".

Biography
Like all Time Lords, Kelner was taken from his family at the age of eight for the selection process in the Drylands. Staring into the Untempered Schism as part of a Time Lord initiation rite, Kelner was inspired by what he saw in the Schism. (PROSE: A Brief History of Time Lords)

Personality
Unlike his predecessor Spandrell, Kelner appeared to be much more political and ambitious. After the Vardan invasion, he assisted the Doctor in removing Time Lords who might oppose the new regime, drawing up lists of those he had a personal grudge against, such as Surgeon General Gomer. At this point he was told by the Doctor to consider himself as acting Vice President. Although Andred disliked Kelner, he stayed in post because he thought he might be able to lead a resistance movement within the Capitol and act as a foil to the corrupt Castellan.

Kelner was equally at home collaborating with the Sontarans, who had used the Vardans as a cat's paw to their own invasion. (TV: The Invasion of Time)