Morlock

Morlocks are one of the two post-human races in H.G. Wells' The Time Machine. Set in the year 802,701 AD, the Morlocks are one of the two species descendant from modern humans, the others being the Eloi. They live in a troglodyte civilization, characterized by caveman behavior.

In The Time Ships by Stephen Baxters, the Morlocks are still a race existing in darkness but are no longer brutish. Due to a second timeline they have achieved great technological advances and dedicated themselves to gaining knowledge of the universe.

Original Novel
In the original novel, the Morlocks evolved from minor social classes, who live on the streets or even beneath Earth's surface, while the ascendant class of society lived in high houses and evolved into Eloi. In the very far future, they rule and hunt Eloi. When the unnamed Time Traveller arrives, he fights them with fire, their greatest weakness, but, unlike some other adaptions, never completely defeats them.

 The Time Machine (1960)
In the first movie adaption, the Morlocks are very similar to their novel counterparts, but their backstory is different: These Morlocks didn't evolve from lower social classes, but instead their existence was caused by wars that destroyed the civilization of the human race. They also have other tactics to lure humans into their underground world. This time, the Time Traveller is able to destroy their home with fire in the end.

 The Time Machine (2002)
In the 2002 movie, the catastrophe that divided the Human race into Eloi and Morlocks wasn't an atomic war, but instead failed blasting operations on the Moon. These Morlocks do not fear the daylight and therefore act as an even higher threat. They are bred into castes: The Hunter-Morlocks, the Spy-Morlocks, and the Über-Morlock. He confronted Professor Alexander Hartdegen and gave him his time machine back, with which the Professor was able to destroy the Morlock-Cave, but afterwards couldn't return to his own time.

The Time Ships
In this 1995 novel by Stephen Baxter, the Time Traveller arrives in another version of the future, where the Morlocks are intelligent and peaceful.

Morlock Night
In this 1979 novel by K.W.Jeter, the Morlocks are more intelligent and therefore also able to use the Time Machine themselves after they stole it.