Arid, frozen mountains
|Points of interest|
Ziost (pronounced /ziɒst/) was 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.
In 6,900 BBY, Dark Jedi fleeing the Battle of Corbos came to Korriban and subjugated the Sith species. Since Ziost became the capital of the ancient Sith Empire soon after the reign of Adas nearly 20,000 years before this event, it is assumed the Exiles either relocated there or were frequent visitors.
At some point, Ziost had suffered from an Ice Age that had changed the world's terrain and climate.
A year after the Battle of Yavin, after being roused on Yavin 4 by the Rebel Alliance, the mutated Massassi Kalgrath came to Ziost hoping to find his people. He was disappointed, having found only a frozen waste.
Lumiya visited the planet and created her lightwhip using technology she found on Ziost. Following the Battle of Endor, she apparently trained her apprentices—first Flint and then Carnor Jax—on Ziost or possibly nearby Korriban.
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 hunter Zekk, ran into Ailyn Vel (alias "Boba Fett") on the planet while the rival bounty hunters were searching for Bornan Thul.
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.
It is interesting to note that when Jacen Solo reflects on the planet of Ziost he describes it as the homeworld of the Sith. There is no mention of Korriban at all. Whether he was referring specifically to the Sith species or the Sith Order is not made clear. The Sith species were known to have their true origins on the planet of Korriban. After King Adas defeated the Rakata in 28,000 BBY, many Sith relocated to nearby Ziost where they re-established their society and were later conquered by Dark Jedi who became the first Dark Lords of the Sith, predecessors of the modern Sith Order.
Whether Korriban or Ziost is referred to as the homeworld of the Sith seems to be a matter of historical record (28,000 BBY and before, to 6,900 BBY and after). In the copious amount of Star Wars literature and media available, both planets are alternatively cited. It could be said that Korriban was the homeworld of the Sith species up until the end of Adas' reign, and Ziost was the homeworld of the Sith up until their defeat by the future Dark Lords, when Ziost became the birthworld of the Sith Order. Eventually, the center of the Sith Order was returned to Korriban, as can be seen by the many prominent Sith Lords buried there.