Murlocs were first seen in WarCraft III. They are a type of humanoid fish race. With the coming of Wrath of the Lich King Murlocs will have their own faction called the Oracles. The faction is meant to be like the Aldor and Scryers faction in Outland. The opposing faction will be the Wolvar.
Murloc origins are shrouded in mystery. This is due not only to the fact that these creatures appeared on Azeroth's shores fairly recently (as far as world history goes, anyway) but also because murlocs shun mortals and rarely, if ever, speak anything but their own garbled language.
What's been known up until now about the fish-men is the following: they are not the most intelligent creatures. They congregate on shorelines in tribes and villages. They have been known, in certain instances to worship enigmatic sea-deities (sometimes including naga). And they seem to care little for the mortal races.
However, recent accounts by select individuals who managed to gather information— either by spying, torturing or surreptitiously gaining the murlocs' trust, have brought some interesting details to light…
First, murlocs may not be as dumb as everyone thinks they are. Several clues point to the fact that their steady infiltration of the world's land masses may be a coordinated effort. Whether or not this enterprise has been undertaken strictly of their own accord is not yet known.
Also, the murloc race may be far older than most believe. Several accounts and clues seem to substantiate this. In fact, it is now believed that murlocs (or, more appropriately, their ancestors) may even pre-date trolls. Of course these ancient murlocs lived in the oceans' depths and therefore were never known to the world's early land-dwelling races. In the last few years, the vile naga have begun reemerging from their watery abodes, causing historians to speculate that their migration may have triggered the murlocs' slow encroachment onto land. Some also guessed that the murlocs might be working in concert with the sinister amphibians.
But perhaps the most startling revelation to come from recent intelligence-gathering efforts was this: the naga may not be the only nightmarish horrors lurking in the seemingly bottomless oceans of the world. Several indicators from the murlocs themselves point to the possibility that the fish-men are but worshippers or underlings of perhaps several deep-sea monstrosities that currently lie sleeping, or at least waiting, in the murky fathoms – and even more disturbing, that the murlocs' emergence is an indication of their incipient awakening.
If that is the case, the mysterious and somewhat underestimated murlocs may be the world's first glimpse at something far more terrifying.