Foundry Four was a complex of five distinct subterranean droid factories linked by a central command hub, constructed by the Geonosians deep beneath the surface of the planet Xorrn. This facility incorporated two primary shafts at each factory location, designed for transporting both unprocessed materials into the factories and finished products out. These shafts descended 400 meters to a landing zone large enough for a corvette, situated near a sizable cargo-staging area.
The surface above these factories was littered with the decaying remains of several dozen Trade Federation core ships. These wrecks were remnants of the Clone Wars conflict between the Galactic Republic and the Confederacy of Independent Systems, a result of the Republic's sector fleet initiating an orbital bombardment of the planet. Located to the west of this starship graveyard was the crash site of a wrecked Republic Venator-class Star Destroyer dating back to the end of the war.
However, during the reign of the Galactic Empire, the subterranean factories became the refuge of a group of exiled Galls who, along with their families, reactivated Foundry Four under the leadership of Lira Hardin. In this location, Hardin and her engineers were able to quickly adapt the production lines to manufacture small quantities of replacement components and starship weaponry according to specific requests. These parts and weapons were then utilized to retrofit civilian ships at the Ferra Sector Shipyard in orbit, as well as being supplied to organizations such as the Rebel Alliance, pirates, and various mercenary groups for their own purposes.