Krem-ling was a psychic vampire native to Drakka. With the aid of his Jukstan servant Marsalla, he insatiably fed off the psychic energy of many species, including the Heemies, Worgs, Benlithulans and Suasion Norbs.
Krem-ling came to Crellium with his Jukstan servant Marsalla and other emissaries of Drakka, where he launched his plan to take over the Yulians' Communal Will, which would enable them to feed off of entire worlds at a time instead of individuals. The Fourth Doctor traced to source of the psychic attack on Yula to Crellium, where he and Sarah Jane Smith found Marsalla and Krem-ling's body. After learning of Krem-ling's pan, the Doctor convinced Marsalla to stop Krem-ling by possessing his body before his return from Yula. Krem-ling's body was destroyed in an explosion set off by Marsalla. (PROSE: The Vampires of Crellium)