Four factions native to the Iron Kingdoms make up the armies of Hordes:

The Legion of Everblight is an army of transformed and twisted creatures who serve the newly-reawakened (but not reformed) dragon, Everblight. The Legion is led by the blighted ogrun Thagrosh, Prophet of Everblight, who discovered the resting place of Everblight's athanc and unleashed the Legion into the world. All of the Legion Warlocks carry a piece of the athanc within themselves. The other Warlocks include Lylyth the Herald, Vayl the Disciple, Rhyas the Sigil and her identical twin sister Saeryn the Omen. The Warbeasts of the Legion are Dragonspawn, hideous eyeless draconic creatures created from dragon blood. The majority of the Legion is made up of blighted Nyss elves but a few blighted Ogrun follow Thagrosh. The Legion has been described as having extremely strong ranged attack options.

The Circle Orboros is a collective of powerful druids that command the forces of nature against their foes. The Circle has been described as very fast, stealthy, with very strong magic capabilities. They control many Warbeasts that first appeared in the Monsternomicon, including the Argus, the Gorax, the Warpwolf, and the Woldwarden. A smaller version of the Woldwarden, the Woldwatcher, appears as one of their light warbeasts. Another creature from the Monsternomicon, the Tharn, appear as a race allied to the Circle. Three of their troop choices are units of Tharn.

HORDES is the name of the newest 30mm tabletop miniature wargame produced by Privateer Press, announced at Gen Con 2005 and released on April 22, 2006. Although a completely standalone game in its own right, HORDES was designed as a companion to WARMACHINE, Privateer Press' flagship miniatures game. The games are 100% compatible, and share much of the same rules set, although the most important mechanic - fury for HORDES and focus for WARMACHINE - remains unique to each. HORDES forces and WARMACHINE forces often face off against each other both on the tabletop and in the background fiction. The games share the same setting, the Iron Kingdoms, with much of the Hordes storyline taking place in the wild areas away from the 'civilized' areas where WARMACHINE's major action takes place.

The Trollbloods are a collection of various troll breeds, banding together to push back civilized nations and forces of the wild from their territories. Trollkin, Trolls, Pygmy Trolls, Pyre Trolls & Dire Trolls make up the Trollblood forces thus far. Matt Wilson of Privateer Press has stated that the Trollbloods will be the 'protagonist' faction of Hordes. In play they are extremely tough and resilient, very strong melee fighters and have some great synergy between various units and the Warlocks. Units released in Primal are the Dire Troll Mauler, Dire Troll Blitzer, Troll Axer, Troll Impaler, Pyre Troll, Trollblood Scattergunners, Trollblood Champions, Kriel Warriors, Krielstone Bearer, Pygg Bushwackers and the Fell Caller.