Kursteliaphaestyxsan (Kurst for short) was an agent of the Celestial Intervention Agency. He worked with fellow agent Levith to capture the Eighth Doctor and supervise Charlotte Pollard during an expedition into the Antiverse.
The Celestial Intervention Agency sent a flotilla of Battle TARDISes and a Class 7C Time Station to capture the Eighth Doctor. After disabling the Doctor's TARDIS with time torpedoes, Kurst and Levith broke into the TARDIS, stabilised the environment and took the Doctor for questioning. Kurst and Levith were then charged with setting up the necessary equipment to open the temporal breach endemic to Charlotte Pollard into a portal to the Antiverse. They were also charged with making sure that Charley came to no harm since a similar portal would be needed to get home.
The Neverpeople telepathically pulled Kurst's memories from him and recited facts of his life to unnerve him. They discovered that he was a cousin of the Patrex Chapter, an under-assassin with the CIA, having been fast-tracked for the position from the Chancellery Guard and kept a striped pig-bear named Stasersnout as a pet and fed it Promaze bars.
After arriving in the Antiverse, a re-stabilised Charley skipped off to explore, with Kurst in pursuit. Kurst found Charley a short distance away, surrounded by hungry Neverpeople. He distracted them by firing his staser at them. The Neverpeople promptly turned on Kurst instead and consumed the temporal energy flowing through him. He was presumably killed in the process. (AUDIO: Neverland)