Mustafar was a small planet located in the Mustafar system, within the Atravis sector of the galaxy‘s Outer Rim Territories. Once a garden world nourished by the Bright Star artifact, its orbit was shifted when Lady Corvax unleashed the energies of the Bright Star in an attempt to return her husband to life. The resulting gravimetric duel between the gas giants Jestefad and Lefrani over Mustafar heated the planet’s core, transforming the lush world into an imbalanced volcanic hellscape. Adapting to life on their devastated homeworld, the arthropodal Mustafarians evolved into two distinct subspecies that cooperated to ensure their continued survival. Legends of Corvax’s search for immortality brought the ancient Sith to Mustafar, seeking the same secrets of eternal life. There, they built a temple over a locus in the dark side of the Force, above the buried ruins of Corvax Fortress.
Acquired by the Techno Union over three hundred years before the Clone Wars, Mustafar’s lava flows were mined for unique and valuable minerals. It was also home to the Black Sun crime syndicate, whose headquarters was located near the mining town that became known as Zitontown after the Falleen Ziton Moj ascended to leadership of the organization. During the Clone Wars, the Mustafarians aligned themselves with the Confederacy of Independent Systems, who used Mustafar to produce battle droids for their droid army. Darth Sidious had a secret facility on the planet where he intended to turn “harvested” Force-sensitive children into Force-talented spies. However, the Sith Lord had the base scuttled when Jedi Knight Anakin Skywalker and his Padawan, Ahsoka Tano, arrived to rescue the younglings.
Mustafar served as the final redoubt of the Separatist Council until the newly-appointed Darth Vader, formerly Anakin Skywalker, was sent by Sidious to slaughter the council, effectively ending the Clone Wars. The Sith Lord was confronted by his wife, Padmé Amidala, and his former Jedi Master, Obi-Wan Kenobi. The latter dueled Vader, defeating him and leaving him to burn on a lava bank. However, Vader was saved when Sidious arrived and carried him offworld. Mustafar then came under the ownership of the Galactic Empire after the Techno Union and its assets were nationalized. Sidious had new facilities built on the planet, where more Force-sensitive infants were taken and transformed into agents of the Inquisitorius.
During this era, Vader returned to the site of his greatest defeat and, with the help of the ancient Sith Lord Darth Momin, erected the massive monolith Fortress Vader to serve as his personal sanctum, built on the site of the former Sith temple. Throughout the Age of the Empire, Vader used the planet to fulfill his master’s biddings, with the fiery world becoming the final resting place for victims of the Great Jedi Purge. In addition, Vader also undertook personal business within his new realm, attempting to wield the dark powers of Mustafar to bring his deceased wife back from the dead.
Following the Dark Lord of the Sith, the Empire took hold of planet. Resource extraction efforts on Mustafar were taken over by the Mining Guild, although strict Imperial travel restrictions on the system made it difficult for the guild to turn a profit and mining operations eventually ceased entirely. Black Sun also abandoned Mustafar for a more low profile world when the Empire established a garrison there. The Mustafarians resisted the Imperial occupation of their homeworld and attempted to drive them from Mustafar by launching multiple assaults on Fortress Vader.
Although it hosted one of the earliest rebel victories of the Galactic Civil War, Mustafar fell into obscurity following Vader’s demise at the Battle of Endor. After the destruction of the Bright Star, the planet’s ecosystem slowly began to heal from the devastation it had endured for centuries prior. Many devout pilgrims journeyed to the ruins of Fortress Vader, hoping to tap into the late Sith’s dark power. Decades after Vader’s death, his grandson, Kylo Ren, journeyed to the world to continue the legacy of his family‘s grisly past. The Supreme Leader of the First Order slaughtered the Sith cult that defended Fortress Vader and discovered his grandfather’s Sith wayfinder, a tool that allowed him to locate the phantom emperor Sidious on Exegol.