Xeriphas, or Xerophas, (PROSE: Time-Flight) was the homeworld of the psychic Xeraphin race. 140 million years BC, Xeriphas was caught in the cross-fire of the Vardon-Kosnax War and devastated by radiation. The fleeing Xeraphin merged into a gestalt and left for Earth. By the early 1980s, Xeriphas had returned to normal and the Fifth Doctor said that they could return. The Tremas Master ended up trapped there. (TV: Time-Flight) He found the android Kamelion there, left over from previous invaders of the planet, and decided to use Kamelion for his own purposes. (TV: The King's Demons)
Iris Wildthyme had escaped from Xeraphas prior to visiting Hyspero. (PROSE: The Scarlet Empress)