Fel Horde

The Fel Horde was a military & political body consisting primarily of Fel Orcs who had pledged service to Lord Illidan Stormrage, the self-proclaimed Lord of Outland during Stormrage's tenure as Outland's warlord. Formed initially out of an army of Orcs who had consumed the Pit Lord Magtheridon's blood & had pledged allegiance to the demon, the Fel Horde grew rapidly in power & prestige following Illidan's victory over the demon & his rise to power as Outland's undisputed ruler. The organization became a prominent arm of Illidan's Forces under the leadership of Kargath Bladefist, hero of the Old Horde & Chieftain of the Shattered Hand Clan and subsequently reclaimed much of the Old Horde's territory including the former bastion of Orcish leadership known as the Hellfire Citadel.

During the course of the Burning Crusade, the Fel Horde clashed with the arriving forces of the Grand Alliance & the New Horde as the two organizations moved into Hellfire Peninsula. With the defeats at Hellfire Citadel and the deaths of both Warchief Bladefist and Lord Stormrage, the Fel Horde as a military was shattered & its survivors scattered into parts unknown, though some eventually pledged themselves to the cause of the New Horde.

Structure & Membership
The Fel Horde was structured in the model of the Old Horde, with clans generally specializing in certain areas. However, the number of clans was greatly reduced and the majority of the Clans were specialized into hit-and-run style guerrilla tactics though there was still a large presence of heavy armored warriors, primarily around and in the Citadel.

The primary body of the Fel Horde were Fel Orcs. Many of the Fel Orcs were either seasoned veterans and former members of the Horde of Draenor that was led by Ner'zhul in the later stages of the Second War (and left on Draenor when the Dark Portal was closed at the end of that conflict) or were captured Orcs who were forcibly fed the blood of Magtheridon, a pit lord who had claimed lordship of Outland & was eventually defeated by Illidan and his allies.

The Fel Horde also made heavy use of demonic minions. The Burning Legion's renewed presence in Outland allowed for Illidan's forces and the Fel Horde to capture & tame many demons and turning them against their former Legion masters.

Trivia

 * Some Fel Orcs in the Hellfire Citadel dungeons have been known to refer to the Fel Horde as 'the true Horde'. It is unlikely this name inspired Garrosh Hellscream's 'True Horde' but the two organizations share the concept of being a Horde primarily of Orcs formed after the Old Horde's downfall. Unlike Hellscream's True Horde, however, the Fel Horde embraced the use of demonic & fel magics.