The ongoing conflict between the Barlocks and mankind had been going on at least since the 38th century, possibly even before, however they were not able to enter Earth's capitol city until the fortieth century, when they had assistance from men from the 20th century.
Details about the Barlocks
Very little is known about the physiology of the Barlocks, however they were humanoid, just like the humans that they were most likely a subspecies of. They even seemed to be stronger, at least more so than the average human. Their evolution seemed to give them an advantage in the dark, which they seemed to be able to see in quite well, however on the flip-side, they were blinded by bright lights.
Their customs and traditions were not well understood. They lived in caves, and seemed to be a fairly primitive tribal society, but they were also interested in conquering human settlements, suggesting that they had either been segregated and desired to retaliate, or weren't allowed to live among humans due to their savagery.
Season 3 (1978):
- The Barlocks were clearly inspired by the Morlocks, an underground dwelling race from the future from H.G. Wells' The Time Machine.