Sardor (PROSE: Doctor Who and the Horns of Nimon) was a Skonnan co-pilot charged with delivering sacrifices to the Nimon. Despite his captain's claims to the contrary, he believed the ship could reach Skonnos in six hours. His tampering caused an explosion which left the ship adrift and the captain dead.
The Fourth Doctor and Romana II happened upon the ship while they were in the midst of repairing the TARDIS. On discovering the two Time Lords aboard the ship, the co-pilot immediately threatened them into repairing it. Upon its completion, he wasted no time in leaving the Doctor behind.
A bully and a liar, he never missed an opportunity to insult the Anethans or lie to make himself appear in a better light. It was the latter trait which led to his downfall. He fibbed to Soldeed that Romana and the Doctor were space pirates who had killed the captain and that it was he who had repaired the ship. Soldeed, the sole remaining scientist of Skonnos, easily saw through the co-pilot's lies and had him thrown into the Complex. There he found Romana and the Anethans and tried to turn them over to the Nimon, claiming that he had brought the sacrifices. The Nimon, knowing that Soldeed would never entrust the task to someone else, killed him on the spot. (TV: The Horns of Nimon)