Fel Horde

The Fel Horde is the army of fel orcs who first served the pit lord Magtheridon and then the Illidari. They are headquartered in Hellfire Citadel and the Black Temple.

The prime constituents (and only example available thus far) of the Fel Horde are fel orcs and the demons that control them.

It is revealed by Caza'rez that the Horde is researching a method to restore the fel orcs to their original state.

History
The Fel Horde was created after the Burning Legion sent Magtheridon to the remnants of Draenor, now called Outland, where the pit lord enslaved and corrupted the orcs with his blood, shattering their wills and ensuring that their minds could do little else but obey the Burning Legion. The Fel Horde was quick to establish its home in Hellfire Citadel and at Magtheridon's command struck out to claim other locations with important confluence of power. Foremost among them being the Black Temple, which Magtheridon personally took over as the staging ground for his campaign of conquest against the remnants of Outland.

Meanwhile the survivors of the Sons of Lothar, realizing that they couldn't defeat the pit lord and his armies, vowed to slow them down. Whenever the Fel Horde ventured deep into Outland, the Alliance was there to carve up their flanks and pick off any stragglers. The Fel Horde and Sons of Lothar would skirmish intermittently for years.

The Frozen Throne
In the aftermath of the Third War, Illidan Stormrage, Kael'thas Sunstrider, Lady Vashj arrived to the shattered realm and sought to seize Outland as their own. Illidan's first action against Magtheridon's Forces was to seal the Dimensional Gateways, his forces covered him in the process. The blood elves and naga aided by a group of draenei led by Akama, who pledged his allegiance to Illidan if he helped him to defeat the pit lord, maintained the battle against the Fel Horde while Illidan closed the portal.

With the Dimensional Gateways closed, the Fel Horde and their demonic masters were cut off from reinforcements, as Illidan's forces laid siege to the Black Temple and claimed it as their own. The Fel Horde was subsequently absorbed into Illidan's army.

The Burning Crusade
Sometime following Illidan's conquest of Outland, he had Magtheridon imprisoned within Hellfire Citadel, where he used the pit lord and The Maker to forcibly corrupt more orcs to boost his growing army, many of whom are unwilling.

The Fel Horde went to war against the Alliance and the Horde during the Invasion of Outland. Eventually, adventurers killed Warchief Kargath Bladefist and brought his fist to their faction's leadership in order to usher in the end of the Fel Horde's reign of terror. Ultimately, the adventurers delved deeper into Magtheridon's Lair. There they slew the Hellfire Channelers that were holding the pit lord captive, and ultimately slew Magtheridon himself. Without Magtheridon's demon blood to taint Outland's orcish population, Illidan could no longer create new fel orcs, but others still operated within the ranks of the Illidari, namely the Dragonmaw clan.

The Dragonmaw, Bonechewer, Shadowmoon were among the Fel Horde clans within the Black Temple, when it came under attack by the Horde, Alliance, and Sha'tar as they invaded the citadel and slew Illidan Stormrage.

While the exact status of the Fel Horde after the Invasion of Outland is unknown, the revelation that the Dragonmaw clan independently left Outland for Azeroth, does suggest that that the Fel Horde may have disbanded.

Leadership

 * - Warchief of the Fel Horde.
 * - In charge of capturing, and converting orcs and Mag'har orcs into fel orcs.
 * - Pit lord, leader of the former Magtheridon's forces, enslaved by Illidan in order to create more fel orcs.
 * - Chieftain of the Dragonmaw clan.
 * - Chieftain of the Illidan loyal Bleeding Hollow clan.
 * - Chieftain of the Bonechewer clan.

Clans of the Fel Horde
The membership of the Fel Horde is largely the remnants of the Horde of Draenor, which was ruled by the shaman Ner'zhul during the time of the battles of the Invasion of Draenor. It should be noted that many (perhaps all) of the clans listed below are in fact divided, and do not universally support the Fel Horde. (For example, members of the Shattered Hand clan also reside in Orgrimmar as its rogue's guild and dutifully serve Thrall.) The Shattered Hand orcs that live in Orgrimmar, however, left Draenor twenty years ago and are not fel orcs (they still have green skins and the such).

For our purposes, however, large groups of orcs from the following clans have been captured, brought to Hellfire Citadel and become fel orcs, and now collectively obey Warchief Kargath Bladefist. While the former leaders of these old Horde clans did not all survive, some clans such as the Bonechewer clan and the Bleeding Hollow clan still operate under the dominance of their own clan-specific Chieftain as well as Kargath.

Main clans

 * Shattered Hand clan: Led by the Fel Horde Warchief Kargath Bladefist, the Shattered Hand were originally comprised of former slaves who rose up against their ogre masters and slaughtered them. The clan now holds much of Hellfire Peninsula from the Shattered Halls within Hellfire Citadel.
 * Dragonmaw clan: Led by Zuluhed the Whacked, the Dragonmaw now reside within Shadowmoon Valley where they have enslaved the Netherwing dragonflight of Outland and provide members of both the Fel Horde and the Illidari with nether drake steeds. Some elite members of the Dragonmaw have ascended to become Nether Drakonid.
 * Bleeding Hollow clan: Led by Grillok "Darkeye", this clan operates out of the settlement of Zeth'Gor in Hellfire Peninsula, but also have forces defending the Hellfire Ramparts of Hellfire Citadel. They are a fanatical and crude clan who fight with a berserker fury and gain the boon of prophecy from their elders, who sacrifice an eye to see into the future.
 * Bonechewer clan: Led by Tagar Spinebreaker, they are a clan of fearsome cannibalistic warriors. Their forces are spread across Outland, with members of the clan found in Hellfire Peninsula along the Path of Glory, defending in the Bonechewer Ruins in Terokkar Forest and also at the Black Temple in Shadowmoon Valley under the command of a Bleeding Hollow dire orc named Gurtogg Bloodboil.
 * Laughing Skull clan: The Laughing Skull clan's former leader Mogor defected to the Warmaul ogre tribe, now members of the Laughing Skull are found working within the Blood Furnace and have a number of ambushers operating in Hellfire Peninsula.
 * Shadowmoon clan: The remnants of Ner'zhul's clan contains many powerful warlocks of which are distributed among the Fel Horde's forces across Outland. They appear to be led by the resurrected Teron Gorefiend.

Minor clans

 * Thunderlord clan: The Thunderlord clan was led by Fenris Wolfbrother while members of the Horde of Draenor. The Thunderlords were transformed into fel orcs through the Blood of Mannoroth and abandoned their ancestral home to join the Fel Horde. At some point Garm Wolfbrother became chieftain but later died.


 * Burning Blade clan: Several fel orc blademasters fought for Magtheridon's Forces as military leaders when Illidan attacked the Black Temple. It is presumed that those that survived swore fealty to Illidan upon their master's defeat and now serve as members the Fel Horde.


 * minor Horde of Draenor clans: Survivors of the other clans that also comprised Ner'zhul's Horde of Draenor that have been converted into fel orcs or absorbed by the larger clans. This potentially includes members of the Lightning's Blade clan, Bladewind clan and any members of the Warsong clan who were trapped on Draenor when the Portal was destroyed.


 * Converted Mag'har: Kargath Bladefist tried to recruit the Mag'har for his agenda following the Invasion of Draenor, but they refused to help him in any way. Years later during the invasion of Outland, some of the remaining Mag'har orcs surviving on Outland were captured and converted into fel orcs through the Blood of Mannoroth in the Blood Furnace. The Fel Orc Converts may be former Mag'har.

Speculation
Although the term Fel Horde has been used to refer to the orcs in Hellfire Peninsula and Hellfire Citadel, mainly the Shattered Hand clan, it is believed that the Fel Horde is a new term for all orcs affected by the demonic corruption that was being siphoned out of the pit lord Magtheridon and were loyal to Illidan Stormrage and his Illidari. It may be somewhat confirmed by the appearance of the Bonechewer and Shadowmoon orcs in the Hellfire Citadel. Illidan Stormrage had gathered tens of thousand fel orcs, apparently of various clans (and not just the Shattered Hand) that would eventually be the Fel Horde.