The Underground, also known as the Triumvirate Underground and originally as the Triumvirate Subversive Intelligence Service, was an organization founded during the height of the Fauthian devastation. With the then-reigning Galactic Federation Triumvirate retreating under the unceasing onslaught from Raixan Fauth's horde, Kyren Zath would suggest and receive approval for the creation of a special force dedicated to protecting the countless beings left behind in the wake of the warlord's conquest.
Its essentially shadowy nature would only increase after the fall of Coruscant in 1120 ABY, when it helped to ferry august personages, such as certain Jedi, away from the heart of Fauthian activity. Using an incomplete Worldcraft as their base of operations, the demoralized Underground would continue to move in secret throughout the galaxy up through 1140 ABY, helping keep valued citizens and vulnerable populaces from suffering too much at Fauthian hands. However, twenty years into the Galactic Interregnum, many inhabitants had deserted the movement and gone on to quiet lives on backwater worlds; the Worldcraft was reduced to a temporary form of transportation to keep its constituents out of the path of the roaming Fauthian horde, manned by a skeleton crew.