Approximately ten years after the arrival of the Sith on Korribanos, Darth Azeroth, along with his fellow Sith Lord Darth Aeris, had themselves put into carbon freeze along with an army of Sith troopers ten thousand strong.
The army was made up of ten legions of one thousand each. An additional ten Legion Commanders were also frozen. These were no ordinary troopers; each Legion Commander was Force-sensitive and given rudimentary Sith training.The purpose of Azeroth's army was to awaken five thousand years in the future, when the Jedi had gotten complacent and forgotten about the Sith. He would then recruit the native Korribanosians into the ranks of the Sith and launch a crusade against the Jedi, hoping to catch them by surprise. At the time of the army's creation, Azeroth couldn't have known that upon his revival, the Sith not only continued to exist across the galaxy, but that many of them had developed peaceful and even friendly relations with the Jedi.
The army was kept hidden a kilometer beneath the planet's polar ice in a huge facility constructed in secret and cobbled together with parts salvaged from dismantled starships. Along with at least one shuttle, the facility also boasted dozens of troop carriers capable of transporting the massive army out of its underground storage upon its revival from carbon freeze.
Although scheduled to be thawed five thousand years after being frozen, an accident forced Lord Azeroth to come out of hibernation a full millennium early. As a result, he had no choice but to accelerate his plans.