The Triumvirate was formed from elements within the Imperial Union which correctly believed Malphuus was a fraud and sought to end his reign. They had a substantial amount of resources, including starships and troopers, contributed by high-level defectors with loyal forces assigned to them. This was bolstered by local conscripts, identifiable by the ragtag armour.
The group took its name from a trio of leaders, each representing both a faction and a species: Admiral Keller, representing humans and Imperials; Gul'dor, representing Jaffa and those loyal to Khepri; and an unidentified Goa'uld, representing those loyal to Sobek. Following Sobek's escape, the System Lord himself assumed leadership.
Rogue Squadron first encountered an agent of the Triumvirate named Polltrok when they tried to recover Nemhain from Malphuus's forces. Posing as a New Republic Intelligence officer, he attempted to steal the ship himself.
Although he failed, Polltrok did escape with intelligence from the ship pointing to the resting place of Project Starthrust. The Triumvirate then began to integrate it into one of their own vessels. Rogue Squadron eventually located Starthrust themselves and destroyed it.
The Triumvirate resurfaced following the Dukhang Crisis, attempting to solidify their power base and build their own empire: first Shedyet by force, then Keshmar by diplomacy. Both attempts were foiled, despite using advanced weaponry contributed by the Goa'uld weapon-smith Kathar.
Subsequently, Rogue Squadron undertook a concerted effort dismantle the Triumvirate. They approached Gul'dor first, successfully persuading him to abandon the Triumvirate and join the Free Jaffa. Before targeting the next faction, Rogue Squadron themselves were approached by Admiral Keller, bringing news that Sobek had activated an ancient superweapon, threatening the entire galaxy. With her help, the superweapon was destroyed, taking with it much of the Triumvirate fleet.
Little has been heard of the Triumvirate since, although some of its human members have drifted towards the Lucian Alliance.