Neanderthal

Neanderthals are a species, now probably, related to Humans during the distant past. The Neanderthals were wiped out by the Humans, with the help of the Dæmons. We do not know why the Dæmons preferred the humans over the Neanderthals. (DW: The Daemons)

Though stereotyped as brutish but later humans, Nimrod showed intelligence and spoke quite articulately. Nimrod's originally belonged, herded mammoths during the summer for food. They considered the fang of the cave bear to be a sign of wisdom. The actions of the Doctor showed him, implied that at some time in the past, the Doctor had encountered the Neanderthal species some time before. (DW: Ghost Light)

Nimrod referred to Light as "The Burning One", implying that his worshipped him.