Kristeva (The Ancestor Cell)

Uncle Kristeva was a member of Faction Paradox notably involved in their invasion of a Gallifrey. (PROSE: The Ancestor Cell) He was one of the Uncles, the Faction's order of assassins. (PROSE: The Gallifrey Chronicles)

Kristeva knew Laura Tobin before her remembrance. (PROSE: The Ancestor Cell)

Nearly three centuries into the future of the War in Heaven, when the surviving Faction had devolved into a militaristic sect, (PROSE: The Gallifrey Chronicles) Kristeva and Mother Mathara lead an invasion of Romana III's Gallifrey (PROSE: The Ancestor Cell) to launch their own front against the enemy. (PROSE: The Gallifrey Chronicles) Mother Tarra was their agent, infiltrating the superstitious youths of Gallifrey driven towards Faction rites by the corrupting influence of the Edifice. (PROSE: The Ancestor Cell)

Traveling back in time to before the Event, (PROSE: The Gallifrey Chronicles) Kristeva manipulated the Eighth Doctor while Mother Mathara's warfleet waited for the invasion. The Faction took advantage of the Edifice's negative affect on Gallifrey's history and culture. Eventually, Kristeva and Mathara infected the Matrix, creating a copy of the Eleven-Day Empire in Gallifrey itself, solidifying their version of Grandfather Paradox, and destroying Gallifrey's eight cloneworlds.

The Doctor obliterated Romana's Gallifrey in an attempt to avert the War, destroying the possible Grandfather Paradox and Mathara's fleet. Kristeva and his Shadow Parliament were destroyed by this, the shock of the event causing them to combust or be attacked by darkened, shadowy birds before the planet exploded. (PROSE: The Ancestor Cell)