World of Warcraft is absolutely full of trolls -- not the trade chat kind, the actual race. Whether you're traveling the southern continents or icy heights of Northrend, the trolls are everywhere; vanilla WoW and both expansions have all included troll content of some kind or another. The original game had Zul'Farrak, Sunken Temple and then later Zul'Gurub. The Burning Crusade didn't see much of the trolls in Outland (beyond a few settlements, of course), but trolls played a large part in high elf (now blood elf) history and currently plague the Ghostlands. Eventually we saw the release of Zul'Aman, and with Wrath's release, we were introduced to the ice trolls of Zul'Drak and their capital, Gun'Drak.
While there have been vague hints -- stone tablets and other records -- documenting the history of the race, there's very little solid information regarding the trolls. Big events have been documented, but the day-to-day life and the origins of the trolls aren't really addressed beyond "they have been on Azeroth since the beginning." Of all the various troll tribes, only one is playable -- the Darkspear tribe that now makes its home on Kalimdor. The trolls of the Darkspear have not only made a new home for themselves upon Cataclysm's release, but they've also found two new paths to follow; players will be able to choose troll druids and warlocks with the expansion's launch. In order to understand the Darkspear, a closer look at its origins and the origins of one of the bloodiest wars in Azeroth's history is necessary.
WARNING: The following post contains spoilers for the upcoming Cataclysm expansion. If you wish to remain spoiler-free, do not continue.
The Gurubashi and Amani Empires didn't particularly care for each other, but they didn't really fight much, either. Their efforts were instead concentrated on the Aqir, a race of insect-like creatures that were intent on claiming the entirety of Kalimdor for themselves. The Gurubashi and Amani Empires weren't too terribly keen about this and spent thousands of years making sure this never came to pass, by beating back the aqir until they split into two different areas of the Kalimdor continent -- Azjob-Nerub to the north, and Ahn'Qiraj to the south.
After the aqir were defeated, the trolls went back to their normal lives -- until the night elves appeared. Stories of the night elves' origins are also shrouded in mystery, but there are ancient troll legends that suggest a group of trolls sought to create their own colony in the heart of Kalimdor, stumbled across the Well of Eternity and were changed into what we call night elves today. The night elves fervently deny this, of course -- mostly because after their origins, the night elves spent the next several thousand years warring with both tribes and carving out a giant chunk of land to claim for their own.
Hakkar brought the Gurubashi Empire the power that it craved, but at a terrible cost: The blood god required sacrifices to be made, and countless souls of trolls were fed to Hakkar in an effort to keep him appeased. This wasn't enough for Hakkar, however, and he demanded that the priests -- who were now calling themselves the Hakkari -- find a way to summon him physically into the world, so that he could feed upon the blood of his victims directly. Some Hakkari were horrified at the idea, but there was a small faction of priests that were entirely devoted to the old blood god and sought to do just as Hakkar wished. These trolls were called the Atal'ai.
The remaining Hakkari were angered at this betrayal and fled north to find the remnants of the Atal'ai swearing themselves to Hakkar's service. The Atal'ai welcomed them with open arms. Together, they sought to bring Hakkar back to life -- and Ysera, Aspect of the Green Dragonflight, discovered their plot. She smashed the temple beneath the marshes, which is why the Sunken Temple today is ... well, sunken. Ysera assigned several green dragons to watch over the area, including her consort Eranikus. Eranikus went into the temple directly and found himself overwhelmed by the dark power of the Atal'ai.
Meanwhile in Stranglethorn, the remaining trolls of the Gurubashi Empire began to splinter and fragment into several different tribes, each tribe claiming chunks of the Stranglethorn jungles and fighting viciously with the others in order to keep hold of their respective lands. It seemed the Gurubashi Empire was no more -- instead, there were mere fragments. These included the Bloodscalp tribe, the Skullsplitter Tribe and a small group known as the Darkspear. The remains of the Gurubashi Empire, now calling itself the Gurubashi tribe, came to the conclusion that it had, perhaps, made a mistake in killing Hakkar's avatar -- after all, despite the sacrifices and the bloodshed, the old god had kept the tribes united. It wasn't until Hakkar's defeat that the splintering began, and so the Gurubashi decided that it would dedicate itself to preparing for the Soulflayer's return, convinced that he would restore the Gurubashi Empire in return for its service.
Soon enough, a fleet of ships carrying orcs washed up on the island. The leader of these orcs was Thrall -- and Sen'jin went to Thrall to warn him of the human encampments on the islands. Thrall, pleased at the information and the newfound allies, offered to drive the humans from the islands, and Sen'jin quickly agreed. After driving back the humans, Thrall, Sen'jin and the other orcs were attacked and captured by murlocs, dragged to their prisons below the island's surface. Thrall escaped and freed many of the imprisoned orcs and trolls, but the murloc high sorcerer was holding Sen'jin in the deepest caverns of the prison, in order to sacrifice the Darkspear leader to a mysterious sea witch. As Thrall arrived to save the troll witch doctor, the murloc struck -- and though Thrall managed to kill the high sorcerer, it was too late. Sen'jin was dying.
With his last breath, Sen'jin told Thrall of his vision and begged him to lead the Darkspear from the island and to a new destiny. The sea witch, furious at the defeat of the high sorcerer and her other minions, sent a gale of storms and waves to batter the island. Thrall and his forces worked to repair the damaged ships of their fleet, and when the repairs were completed, Thrall went to Sen'jin's son Vol'jin and offered him and the remaining Darkspear a place in the Horde. Vol'jin took Thrall's offer gratefully and sent some of his forces with Thrall. Vol'jin and the remaining Darkspear stayed on the islands for roughly a year after Thrall's departure, gathering supplies and then setting sail for Durotar, where they made their home on the Echo Isles. Despite Thrall's welcome reception, the trolls of the Darkspear found themselves having to adapt in drastic ways to their new life in the Horde ...