Ziost (pronounced /ziɒst/)[3] was once a world made up entirely of an ancient dark forest. However, the trees withered away and the planet became very similar (in landscape) to Korriban. Much of the planet was covered in ice. Not only was it a focal point of the dark side, but it was also the adopted homeworld and Imperial capital of the Sith species, who left their original homeworld, Korriban as a graveyard world after the death of their leader Adas.
Ziost became the capital of the ancient Sith Empire after the reign of the Sith Overlord Adas came to an end. Without his unifying force holding them together, the Sith degenerated into their previous feudal ways. After centuries of battle and strife, the remaining Sith utilized Rakatan vessels to relocate to other planets, leaving their desolated homeworld Korriban as a vast graveyard world populated by religious fanatics, who would thousands of years later, be subjugated by the Jedi Exiles, forming a new Sith Empire.[1]
At some point, Ziost had suffered from an Ice Age that had changed the world's terrain and climate.
Ziost's existence was largely forgotten after the Battle of Ruusan, due to the secrecy of Darth Bane's SithOrder. Many ancient and evil secrets remained on this place of great dark power.
A year after the Battle of Yavin, after being roused on Yavin 4 by the Rebel Alliance, the mutated MassassiKalgrath came to Ziost hoping to find his people. He was disappointed, having found only a frozen waste.
Almost a decade later, the Jedi scholar Tionne set out to find Kalgrath. She traced his trail as far as Ziost, but there it disappeared. Another ten years later bounty hunterZekk, ran into Dengar on the planet while the rival bounty hunters were searching for Bornan Thul.[4]
At the time of the Second Galactic Civil War, Jacen Solo (overseen by Lumiya) dispatched Ben Skywalker to the world, supposedly to recover a Sith amulet, but in reality to test him against opponents, to see if he was worthy of becoming a Sith apprentice. After having an epiphany of sorts, Ben accompanied the stranded child Kiara across the surface of the planet, led by mysterious voices to an ancient temple. Throughout his journey the young Jedi was attacked by neks and pirates orbiting the planet under the command of Byalfin Dyur. Ben escaped the planet eventually, finding an antiquated but extremely powerful Sith Meditation Sphere in the ruined temple, and took the attack to the pirates.
Though Ziost was established as the original Sith homeworld in The Golden Age of the Sith, many sources described Korriban as the Sith homeworld. It was the "public" capital world of the Sith Empire during the era of Darth Revan, but was a mausoleum-world for millennia beforehand and would return to such a state not long after.
The controversy was put to rest in the article Evil Never Dies: The Sith Dynasties by Abel G. Peña, which clearly established the Sith originating on Korriban and relocating the capital to Ziost before the arrival of the Dark Jedi exiles during the Hundred Year Darkness, though the Dark Jedi exiles themselves landed on Korriban.
Without Adas' unifying influence, wars once again raged for rule of the Sith people, with the reigning combatants arrogantly claiming the title of Sith'ari, and eventually forcing a relocation of the Sith capitol to the planet Ziost. Eventually, almost two-dozen millennia after Adas' death, a proper successor to Adas seemed to come at last. Known in Republic space as the Exiles, traitorous Jedi defeated in a galactic war called the Hundred-Year Darkness arrived on Korriban and cowed the Sith people with their astounding Force abilities, lightsabers, and superior technology.
In the Star Wars: The Old Republic demo of the Eternity Vault at PAX Prime 2011, General Threnoldt mentions Rakata Inscriptions in a place called the Ziost Abyss, suggesting that the Rakata may have once had a major presence on Ziost. These inscriptions, discovered and translated by the Imperial Reclamation Service, are said to describe a Rakatan prisoner on Belsavis called The Infernal One. It is currently unknown whether this information regarding Ziost is canon or will make a final appearance in game.