|Distance from Core||53,000 Light Years|
|Region||Outer Rim Territories|
|Number of suns||2|
|Affiliation||CIS, Galactic Empire|
The planet is covered by hundreds of caldera, most of which are in a state of constant eruption. The volcanic activity is caused by gravitational stresses on the planet created by the two gas giants that affect its orbit (similar to Jupiter's Galilean moons). An automated energy and mineral collection facility on the planet is used by the Separatist Council as their last headquarters.
Despite its hellish conditions, Mustafar has developed native lifeforms. A sentient race known as Mustafarians developed in the cooler hollows of the planet. They are divided into two subspecies: the tall, thin Northern Mustafarians (led by the enigmatic "Maverick Main") and the shorter, hardier Southern Mustafarians (aka "The Mustafar Rats"). The Techno Union took an interest in the planet and the mineral-rich molten rivers covering its surface, and employed the Mustafarians to mine these minerals. The Mustafarians made use of native "lava fleas," as well as the Techno Union's technology that gave them further protection from the heat. The natives had little interest in outworld politics and were content to work on their homeworld.
Confederate World 
As a planet controlled by the Techno Union, Mustafar was a member of the Confederacy of Independent Systems, but remained largely untouched by the Clone Wars. As the war progressed, Count Dooku and the Separatist Council saw fit to build a fortified stronghold on Mustafar to be used in the event that the war against the Galactic Republic did not go well. The Techno Union, the Commerce Guild and the Trade Federation funded the costly fortress, which was designed to be able to withstand any prolonged assault. Mustafar's terrain and environment made it difficult enough to reach the bunker, but it was designed so that even if enemies could negotiate the terrain, they would be unable to take the fortress. Tractor beam and ray shield technology protected it from the lava rivers and its interior chambers were climate-controlled. This bunker was the setting for the duel between Darth Vader and Obi-Wan Kenobi.
After the defeat of the Separatists in the opening battle scene of Revenge of the Sith, Darth Sidious orders the Separatist leaders moved to the Mustafar fortress. Soon afterward, he dispatches Darth Vader (the recently corrupted Anakin Skywalker) to assassinate the entire Separatist leadership. Vader is tracked there by Obi-Wan Kenobi, culminating in a climactic duel.
During the course of the fight, Kenobi slices off the lower halves of Vader's legs and his left arm. Vader falls near the shore of a river of lava, where his robes catch fire, burning off most of his skin and hair and severely damaging his lungs. It is these wounds that force him to wear the black life-support suit in which he appears in the original Star Wars films.
Expanded Universe 
Mustafar appears in the video game Star Wars Battlefront II. In the game, Gizor Delzo, a Geonosian who was in complete denial of the separatist Geonosian leader Archduke Poggle the Lesser being killed and still with the idea that the Clone Wars were occurring, planned to start another attack on the "Clone Army". He reactivates a droid factory and begins creating a new droid army. He acquires engineering drawings for a new, superior battle droid, but his plans to use these droids are foiled when Vader's 501st Legion destroys the factory. After the level is over, a cutscene tells that the Empire destroyed the entire factory to eliminate the threat of the creation of another droid army by Gizor Delso. It also appears in the game Star Wars: Empire at War.
Concept and creation 
In the earlier drafts for Episode III "Mustafar" was called "Mufasta"
Star Wars creator George Lucas has on multiple occasions used ideas in his films that had been considered but not used in earlier projects. Mustafar originated from rough drafts of the script for Star Wars Episode VI: Return of the Jedi, which describe a similar world for the setting of the final battle between Vader and Luke Skywalker. The novelization of Return of the Jedi mentions that the duel between Obi-Wan and Vader which led to Vader's terrible injuries happened very close to a "molten pit," in which Vader had fallen after losing to Obi-Wan.
On screen, the Mustafar scenes were realized through a combination of film of Mount Etna, models and computer generated effects. One effect used was backlit methyl cellulose. Ultra-powerful lights from the bottom of the "lava" flow produced the glow of the molten rock.