The Horde was one of the most powerful organisations in Season 2, that was founded by Slip in the late stages of Season 1.
The Horde power structure was comprised of four horseman, Death, War, Strife and Fury, plus their respective captains as the second in command. Each Horseman ruled over a section of Ragnarok, divided into four sectors, and dealt with various Horde affairs. The Horseman switched a few times through Season 2
The Original Horsemen (Left to right; RBG-Fury, Krispy-War, Slip-Strife and Tarterus-Death)
The Original Era of The Horde was comprised of the construction of Ragnarok and the formation of power structures. At this point, the Horde functioned much like a mafia, and was just beginning to assert it's dominance over the world.
The Second Era Horsemen (Left to right; Hades-War, Tarterus-Death, Slip-Strife, RBG-Fury)
The Second Era of the Horde was characterised by the gaining of influence and power. At this point, the Horde had gained a reputation for having some of the most powerful fighters and richest members of the server. Tarterus was beginning to become the front-running leader of the Horde.
The Imperial Horsemen (Left to right; RBG-Fury, Omni-Death, Emperor Tarterus, Comet-War, King-Strife)
The Imperial Horde occurred when Tarterus (Former Death), took control of the Horde and declared himself Emperor. He brought in some of the most powerful faction leaders at the time; (Omni, from the Unsleeping City, and King, leader of the Soul Veins). To attempt a hostile takeover of every other faction in the world that refused to assimilate into the Horde. Many battles took place. Firstly, the takeover of the dwarven fortress Hopestone, and the subsequent looting of their riches. Second, the takeover of the Enderian Outpost. Finally, the Horde attempted to take control of The Cafe, a beloved place for the entire community. This ended poorly, with an underestimation of the support that would be given to The Cafe, eventually ending in the defeat of the Horde.
As a result of this crushing defeat, the Horde began to lose those loyal to it, eventually disbanding upon the death of Tarterus at the Unremembered Tower.