- "The call of Korriban is strong, but it is the call of the dead."
- — Darth Sion
This remote planet was the seat of the ancient Sith race. Korriban was the sole planet in the Horuset System, located across the galaxy from Cinnagar and Koros Minor. It was orbited by seven moons, and was unknown to the Old Republic before the rise of Naga Sadow.
It was to Korriban that the ancient Dark Jedi fled, after they were exiled by the Jedi Knights. Korriban was a desolate world which, under the pall of Sith magic, became more hellish and dangerous. The native life there was twisted by the Dark Side, and the ghosts of Sith Dark Lords buried in the Valley of the Dark Lords roamed everywhere.
The Sith Lords erected huge palaces and burial complexes, which honored not only the dead Lords but the current magicians as well. These ancient Sith enslaved the local population and put them to work building a huge monastery and excavating the Valley of the Dark Lords, then killed the planet's inhabitants once the jobs were done.
Exar Kun was led here by Freedon Nadd's spirit, in an effort to recover certain Sith manuscripts. In the wake of the Great Sith War, the planet was virtually abandoned, although a few settlers managed to eke out a meager living. Those Jedi Knights who remembered Korriban, either through research or direct experience, referred to the planet as the 'cradle of darkness.'
After the Battle of Naboo, the Commerce Guild established a base of operations on Korriban, ostensibly to attract corporations to a tax-free environment. The true nature of the Guild's presence was the accumulation of a droid army, in anticipation of supporting the Confederacy of Independent Systems. Years later, Emperor Palpatine often visited Korriban, to help him center himself in the Dark Side of the Force.
When Emperor Damascus took power and built the third Death Star, he targeted Korriban to test the battlestation's superlaser. The planet was destroyed, but the accumulation of thousands of years of Dark Side power remained. This attracted the Darksider Sivter and his Cult of Shadow, who eventually devised a process to siphon Korriban's Dark Side energy into special crystals.
Horuset is a very small system. Korriban was the only planet located in it. The only other stellar bodies of note are two debris fields.
- Korriba Scar - The innermost of the two debris fields orbiting the star of Horuset.
- Korriban - The only planet in the Horuset System, it was located in between the Korriba Scar and the Ashes of Korr. It is now another debris field thanks to the third Death Star.
- Ashes of Korr - The outermost of the two debris fields orbiting the star of Horuset.
- Valley of the Dark Lords - This valley was the site of the tombs of the ancient Dark Lords of the Sith. The valley itself was located far from Dreshdae, and was continually covered by clouds. It was dominated by huge funereal temples and tombs, with an ornate altar at the far end. The Valley was more than 1,200 meters deep in some places, although it was little more than a slit in the ground, and much of the rock which made up its walls had been carved with magical Sith runes and glyphs to ward off unwanted spirits and intruders. In additon to these runes, a wide variety of sculptures and reliefs adorned the Valley walls, portraying the heroics of the Sith Lords buried there. It was believed that the structure and placement of the tombs was designed to concentrate and focus the power of the Dark Side of the Force, allowing the spirits of the ancient Sith Lords to remain closeby.
- Valley of Golg - This was one of the main branches of the Valley of the Dark Lords.
- Eternal Pyre - The Eternal Pyre was a great pyre located near the Valley of the Dark Lords that was said to burn since the formation of the planet.