Ten generations before 2007, the Krillitane conquered Bessan, killing millions. They took bat-like wings from the inhabitants (TV: School Reunion). In 1140, Lozla Nataniel Henk attempted to breed Krillitanes in Worcester, but was defeated by the Tenth Doctor. By using their own oil against them, Henk attempted to create a huge, mutated Super Krillitane that he could sell to the highest bidder as a weapon. However, the creature was killed when Captain Darke threw a vial of Krillitane oil into its mouth as it was rampaging around the city of Worcester (PROSE: The Krillitane Storm).