Stronghold One was a subterranean fortress built in a volcanic mesa on the planet Makeb. Constructed during Makeb's early mining boom for the planet's treasury, it was submerged inside a lava pool with one surface access points and six separate levels of defenses. During the Conquest of Makeb, the InterStellar Regulators turned over the treasury to the Hutt Cartel, which also stored their reserves of isotope-5 within the vaults. Under the command of Szajin, scientists designed and built isotope-5 droids within Stronghold One. The Sith Empire raided the facility in an attempt to steal the isotope-5 reserves, only to find the Hutt army of isotope-5 droids instead.