The warlock may be one of the most interesting classes in terms of its lore in the whole World of Warcraft - warlocks come from many roots, as many different people throughout history have succumbed to the lure of absolute power offered by the demonic beings of the Twisting Nether. In terms of chronological history, the warlock dates back to the time before the fall of Sargeras, when the corrupting Nathrezim would offer demonic secrets to mortals and use them to help unmake their own worlds. Sargeras defeated the Nathrezim (today known as Dreadlords) but their all-consuming evil and corruption bothered him greatly. In a way, they successfully corrupted a Titan, for it was in contemplating what their existence meant for the cosmos that Sargeras fell, becoming the Dark Titan who would come to create the Burning Legion.
The first beings to call themselves warlocks, as far as we know, are the eredar. Once corrupted by Sargeras, the arcane mages of their race abandoned their study of the mystical forces of creation, favoring the destructive power of the Twisting Nether and the demons that served the Dark Titan. As great as they were as mages, the newly fallen eredar became warlocks of astonishing power. The eredar warlock tradition would become the most widespread - warlocks from the satyrs to the orcs owe their warlocks to those of the Legion. But make no mistake - it is impossible to assume that the warlock you may happen to be dealing with is beholden to the Legion. Many, if not most, serve no other master than themselves.
This is not to say that warlocks cannot, or do not, cooperate. Indeed, in many ways, warlocks are required to cooperate, for in most societies on Azeroth they are despised. One need look no further than the recent events of the Siege of Orgrimmar - Garrosh Hellscream, himself no stranger to a hunger for power, decided that the warlocks who served the Horde could not be trusted and he took great pains to execute them even while he experimented with dark shamanism and sha corruption. Part of the reason for this is the fate of the Old Horde, and their world Draenor, under the secret rule of the Shadow Council, a collective of warlocks controlled and ruled in turn by Gul'dan. While not all races have as immediate a reason to hate warlocks as those of the Horde (who have that example), none truly loves them - be it humans, gnomes, dwarves, or worgen those of the Alliance who can become warlocks are just as secretive as their Horde counterparts. Of the Horde races, forsaken and blood elves are the most likely to be tolerated by their societies, with goblins just behind them.
Be not mistaken, however - no society does more than tolerate the warlock. And this is because, to a great degree, warlocks do no more than tolerate everything. All that exists is fodder for the warlock's quest for power - in many ways, Gul'dan is the personification of the warlock, shorn of any pretense.
In addition to the orcish warlock tradition, the races of Azeroth have long harbored warlocks since the first coming of the Burning Legion. At the end of the War of the Ancients, those warlocks who had once been Highborne of the Kaldorei were now their own race, the satyr, following in the hoofprints of Xavius. But this didn't prevent their high elf descendants from re-learning the art, because the true secret of the warlock is twofold -- there will always be those that seek power and there will always be demons waiting to offer it to them for a price. Rare is the warlock that manages to avoid all the snares these entities lay in their path, but it happens, and those warlocks that learn to compel obedience from demons without losing themselves in the process are among the most dangerous entities on modern Azeroth.
Kanrethad's brow furrowed and he growled, "Which is why we swear that if any member of this council breaks the contract and fails to return or returns alone, the others shall strike them down and banish their soul forever. We either succeed together or die alone."
Some would argue the Council of the Black Harvest is one such group. Formed and guided by the will of Kanrethad Ebonlocke (and no, I don't know if he's related to the Darkshire Ebonlockes) this collection of warlocks sought to wrest power from the most powerful - entities such as Illidan Stormrage, Cho'gall, Ragnaros and even Deathwing himself. The Council is a perfect example of the dichotomy of the warlock's life. One must be able to rely on something outside of the self, but one can never rely too much on it. Trust must be warranted and moreover guaranteed. The fact that the Council split into three pairs, and their loyalty guaranteed not only by oaths but by a pragmatic decree that any of their ranks who returned without their parter would be slain shows us exactly how warlocks approach the world. One can only truly trust in one's own self, unless a guarantee can be found - this principle works when dealing with demons or your fellows.
Those few warlocks who truly mastered their craft were also masters of this dance, between the supreme selfishness and hunger for power that makes the class feared, and their canny understanding of social dynamics and negotiation that makes the class work. We think of Gul'dan today as a titanic figure of evil, but all that he accomplished was with the help of his Shadow Council, with figures such as Cho'gall and Teron Gorefiend at his side. Archimonde and Kil'jaeden were perhaps the two most powerful warlocks in existence, but without the Legion, what could they truly have accomplished? The existence of the Council of the Bitter Harvest, and of groups such as the Burning Blade show that warlocks tend to look for groups to help them achieve their personal goals, even if this means they must come to aid others with theirs. The warlock is more than power hungry - she thirsts for knowledge, and the mastery of the world outside the self that knowledge brings.
Next up, we're going to name some names. Who are these greatest of all warlocks? From whence do they draw their terrifying power? And what are the long lost secrets they seek to exploit?
While you don't need to have played the previous Warcraft games to enjoy World of Warcraft, a little history goes a long way toward making the game a lot more fun. Dig into even more of the lore and history behind the World of Warcraft in WoW Insider's Guide to Warcraft Lore.