Exxilons
The Exxilons were an ancient humanoid race that were technologically advanced. They master space travel and visited planets while they were primitive worlds. They were so advanced that they built a monument that was beyond their control. This folly brought about the destruction of their civilizations causing their race to degenerate into a primitive tribal society.
Biology
After their descent into savagery, the Exxilons developed two distinct groups. Both had bark-like skin, inset eyes, flattened noses and wide mouths. Both groups were nocturnal and their large eyes adapted to the dark. One of the groups was tall and powerfully built, allowing them to live on the surface. The second group were underground dwellers and they were small, paler, and had fluorescent markings on their bodies.
Culture
The surface dwellers had little in the way of culture. They banned the use of technology and any form of progress. They lived near the Great City and protected it from intruders.
The underground dwellers retained much of the knowledge of the original Exxilons and feared the Great City as a danger.
Appearances
Death to the Daleks (TV)
The Left-Handed Hummingbird (Prose)
The Quantum Archangel (Prose)
The Exxilons (Audio)