Over a thousand years before the Galactic Civil War, the Near-Human Sith Lord Quorlac Fornayh traveled to Yorgraxx and enslaved the native species, using them to build his fortress before exterminating them. Within this fortress, Fornayh sought to create a new type of Sith mutant—the Coloi—in an attempt to overthrow the Sith Empire of his time during a conflict with the Galactic Republic. After this conflict began to turn in the Republic's favor, Fornayh retreated to his fortress, hoping to build up his forces and finish developing the Coloi creature.
During the Galactic Civil War, the Galactic Empire scout ship, Predator's Beak crashed on the planet, which eventually reawakened the spirit of Fornayh. This created a disturbance in the Force which Emperor Palpatine felt on Coruscant, and he sent Emperor's Hand Jallar Golin to Yorgraxx to investigate it. The Rebel Alliance ship Griffon's Wings was attacked above the planet by Imperial Guardian-class light cruisers and crash-landed. The Rebel survivors joined forces with the survivors of the Imperial crash and defeated Fornayh's spirit in the fortress. Golin then arrived and encountered them.
Yorgraxx later became part of the Imperial Remnant.
- The Essential Atlas