The Morlocks are a group of homeless mutants who live in the sewers and abandoned subway tunnels underneath New York City. The Morlocks consider themselves a "tribe", a society living undetected or ignored by those who live above ground in the city. Most of the Morlocks are mutants whose mutations are such that they cannot pass for human without assistance; others, until recently, had their looks altered by the mutant named Masque. Many of these mutants have abilities that have altered their looks to the point that they cannot pass for an unaugmented human.
No one is certain how the Morlocks first came to be. The name "Morlock" is taken from the future underground dwellers in H. G. Wells's The Time Machine. It is believed they have been living in the tunnels for at least two generations. Quite possibly, the Morlocks were not originally composed primarily of mutants; over time, however, the mutant population among the Morlocks grew until the term "Morlock" and "sewer-dwelling mutant" were synonymous among the homeless population.
The Morlocks' leader is a woman named Callisto; Callisto has said that she found, rather than founded, the Morlocks following a horrible disfigurement. Callisto proved to be a natural leader, and is considered their leader by almost all the other Morlocks.
The Morlocks first came to the attention of the rest of the superhuman community when a number of Morlocks, acting on Callisto's orders, kidnapped the mutant adventurer Angel in a bid to make him her "mate". This drew the Morlocks into conflict with Angel's teammates, the X-Men; it was through their efforts as well as those of Angel's girlfriend, Candy Southern, that Angel was released, though Callisto has said that one day Angel will be hers. Callisto then pledged that the Morlocks would not kidnap anyone ever again. They have since twice assisted the X-Men.
Masque was one of those who disagreed with Callisto's decree. Backed by a number of other disgruntled Morlocks, Masque made a bid for leadership, only to be defeated in single combat by Callisto and then exiled from the tunnels. Masque then led his followers in building a rival tribe of Morlocks by kidnapping and disfiguring a number of mutant children. The X-Men and private investigator Karen Page put an end to this scheme, forcing Masque to return the children he kidnapped, but there were hints that Masque did not release all those he'd kidnapped.
Other than Callisto and Masque, Morlocks of note are: Caliban, an albino who can sense other mutants; Leech, a green-skinned bald boy who generates an uncontrollable anti-power field; Sunder, a mentally retarded man with superhuman strength but lacks superhuman durability; Tar Baby, whose skin is black and sticky; Skin, a teenager whose skin (but not his muscles or bones) is elastic and prehensile; and Erg, who is able to shoot energy from one of his eyes.
Recently it has been revealed that there are other tribes of homeless mutants living underneath other cities as well, most notably Los Angeles; Chicago; Philadelphia; London, England; Paris, France; and Tokyo, Japan; all calling themselves "Morlocks". The implications of this revelation have yet to be explored. At the least, it is apparent that there is an outside party who is creating tribes of Morlocks in cities around the world, but for what purpose is unknown. Members of the Chicago tribe recently encountered Iron Fist and his allies in Knightwing Restorations, while the Los Angeles tribe ran afoul of Spider-Woman during one of her cases (see Knight, Misty; Wing, Colleen).
First Post-Reboot Appearance: UNCANNY X-MEN #