Mortakk

Mortakk was noted as the blackest character in Silurian history in a parallel version of Earth.

Biography
Mortakk's crimes included conducting genetic experiments on both Silurians and Sea Devils. He was later tried and believed to have been executed before the great hibernation. However, his base was located in an abandoned nuclear research centre at Darkmoor and the Doctor, along with Bernice Summerfield and the Silurian scientist Thactus of URIC travelled in the TARDIS to confront him.

Mortakk had indeed survived and created a gas with mutagenic properties that forced Silurians or humans to evolve into hybrid creatures containing both reptilian and mammalian qualities. This brought him into conflict against his enemies, and Mortakk himself fought the Doctor in a sealed room when the gas was released. However, due to his Gallifreyan biology, the Doctor was not affected and Mortakk was killed in the battle. (DWM: Final Genesis)


 * It is not known whether Mortakk existed within the mainstream Earth.