The Trolls and the Horde are short essays included as part of the Troll Compendium on the old official site. It is reproduced here, in case the archive of the pages disappears.
The Trolls and the Horde
Below you can read the story of how the trolls came to join the Horde and of their history within it. Beginning with the Second War, continuing through the enslavement of the orcs and the renaissance of the Horde under Thrall, and up to the death of Sen'jin and the settling in Durotar, the trolls have played a vital role in the history of the Horde.
Forest Trolls and the First Horde
Early in the Second War, the isolationist elves took little interest in the war's progress and provided only token support to the Alliance of Lordaeron. Then Warchief Orgrim Doomhammer offered the forest trolls a place in the Horde. If the trolls accepted, Doomhammer promised that the Horde would vanquish the high elves and assist the forest trolls in reestablishing the Amani empire.
The forest trolls' leader, Zul'jin, declined the tempting offer at first. As a famous hero of the Amani tribe, he had accomplished an amazing feat by uniting all forest trolls under his rule. Still, the forest trolls were primarily interested in fighting the high elves, and Zul'jin was skeptical about the Horde's plans. A short while later, human soldiers captured a war party led by Zul'jin. When the Horde rescued the trolls, Zul'jin changed his mind and agreed to an alliance with the Horde. A few tribes of forest trolls joined their new allies on the battlefield. Shortly thereafter, the Horde burned down the borderlands of Quel’Thalas and slaughtered many high elf civilians. Furious at this wanton destruction of life, the elves subsequently committed all their resources to the war.
By the time the Horde was driven back, however, the orcs and their allies had already achieved their true goal: to steal and desecrate many of the Runestones that powered the elves’ defensive shield. The warlock Gul’dan then used the pilfered stones to power his devious Altars of Storms.
Nevertheless, the Alliance ultimately won the Second War, and after a number of additional battles, most of the vanquished orcs on Azeroth were rounded up and placed in internment camps. In the war's disastrous aftermath, many forest trolls were furious at the Horde's failure to carry out its promise and deserted their former orc allies without a moment's hesitation. Today only one tribe of forest trolls--the Revantusk tribe--is loosely affiliated with the Horde, much as the Wildhammer clan of dwarves is associated with, and yet not a member of, the Alliance.
Although the Second War ended some years ago, the Dragonmaw and Blackrock orc clans and their allies--among them two tribes of forest trolls--have not given up trying to defeat humanity. Referred to as the Dark Horde by outsiders, this group is led by the orc Rend Blackhand, who has named himself warchief. A force of approximately five thousand strong, the Dark Horde regards itself as the true Horde, and believes that Thrall and his followers are foolish weaklings. Rend's forces reside in Blackrock Spire, and they have allied themselves with the black dragonflight.
Rebuilding the Horde
Before the Third War broke out, the courageous orc Thrall escaped his enslavement and began assembling a new Horde. This Horde would make no pacts with demons, nor would Thrall and his orcs seek further conflict with humans. Instead, at the urging of a prophet, Thrall led the revitalized Horde over the sea to Kalimdor.
The voyage grew perilous when a violent storm appeared and inflicted heavy damage on the orc fleet. Fearing that the ships would not reach Kalimdor intact, Thrall ordered the Horde to seek shelter in the cove of a nearby island. The elderly leader of the Darkspear trolls, Sen'jin, greeted the orc newcomers and warned them that a group of humans had established an outpost on the island.
Unfortunately the humans were not the only threat on the island. A group of murlocs captured Sen'jin, Thrall, and several other orcs and trolls. Thrall fought his way out of his prison cell and freed a number of other captives, but by the time he reached Sen'jin's cell, the wise old troll was missing. The murlocs had taken him away in order to sacrifice him to a mysterious sea witch.
Despite Thrall's best efforts, a murloc sorcerer succeeded in carrying out the sacrifice. Mortally wounded, Sen'jin revealed that he had seen a vision in which Thrall would lead the Darkspears from the island.
The sea witch was furious at the slaughter of her minions and the defilement of her sanctuary. She summoned powerful waves to batter the island. Regardless, Thrall and his forces managed to defeat further murloc attackers, repair the damaged fleet, and retrieve a number of troll survivors.
In Sen’jin's honor, Thrall offered the Darkspears a place in the Horde and sanctuary in the kingdom he planned to establish in Kalimdor. Vol’jin, the son of Sen’jin, took control of the Darkspear tribe and accepted Thrall's offer. After the orcs departed, a large group of Darkspears also sailed for Kalimdor. Vol'jin and the rest of the tribe weathered the sea witch's anger, gathered all the supplies they could take with them, and joined their brethren roughly a year later in the new orc nation, Durotar. They made a home for themselves on the Echo Isles, just off the southeastern coast.
Further Turmoil for the Darkspear Tribe
The Darkspears were not to know peace for long. After the Third War, Grand Admiral Daelin Proudmoore led a large fleet of battleships against Thrall's forces on Durotar. Proudmoore could not be convinced that this new Horde was any different from the corrupted Horde of the First War. Under heavy attack, the trolls were forced to evacuate to the mainland of Durotar, but the Horde managed to defeat the misguided admiral.
Much relieved, the Darkspear trolls began returning to the Echo Isles, only to be betrayed by one of their own. A witch doctor named Zalazane used dark magic to rob several other trolls of their free will, forcing them to obey him. As his influence spread, his army grew while the number of free Darkspears dwindled. Fearing that all of his people would fall to Zalazane's insidious sorcery, Vol'jin ordered the tribe to abandon the Echo Isles.
Thus, the free Darkspear trolls left the islands and created the fishing village of Sen’jin on the Durotar coast, just northwest of the Echo Isles. Some Darkspears have remained in the village, and others have ventured farther afield. Vol'jin himself dwells in Orgrimmar, the capital city of Durotar. Orcs make up the majority of the city's inhabitants, but there is a strong troll presence in the Valley of Spirits.
Today the Darkspears and their allies frequently strike at Zalazane's holdings on the Echo Isles, determined to win back the trolls' first home on Kalimdor. In the meantime, Zalazane has not given up in his efforts to enslave his entire tribe, and so he continues to send his trolls to the mainland in order to drag further Darkspears under his sway.