Duel on Mustafar The Duel on Mustafar was a confrontation where the recently apprenticed Sith Lord Darth Vader , formerly Anakin Skywalker , fought his former best friend , and Jedi Master , Obi - Wan Kenobi , on the planet Mustafar in the Outer Rim . After learning of Skywalker ' s downfall from Grand Master Yoda at the Jedi Temple , Kenobi arrived on Mustafar , where he attempted to reason with Vader , not believing Emperor Palpatine , also known as the Sith Master , Darth Sidious , had taken control of his mind . However , Vader no longer cared for their friendship , and quickly claimed that Kenobi was his enemy ; the pair then ignited their lightsabers and locked blades , fighting through the murder scene in the Klegger Corp Mining Facility , where Vader had recently slaughtered the members of the Separatist Council , the legislative branch of the Confederacy of Independent Systems . The fight progressed on the structures of the massive facility that hovered over the deadly lava of Mustafar . Kenobi and Vader soon found themselves trapped on a structure collection arm connected on the facility when it was separated from the facility by the lava and descended onto a hot stream . Kenobi managed to fall onto a lava skiff that was heading in the opposite direction of the fallen collection arm in the stream . Vader soon followed and jumped onto a droid collector where the two continued to fight . Kenobi managed to jump onto a high lava bend slope , and claimed that the duel was over due to his advantage . The Sith attempted to follow , but Vader , in his hubris , failed to block Kenobi ' s final attack , a powerful maneuver , which severed Vader ' s remaining organic limbs , and Vader rolled down to the edge of the lava bend , bringing the duel to an end . Then , Kenobi — overcome with disgust and remorse over his friend ' s transformation — cried out that he had believed that Vader was the Chosen One and his destiny was to destroy the Sith , but instead he joined them . Unable , but most likely unwilling , to connect with his former best friend , the Sith was consumed by the fires of the lava that leaked onto the lava bend ; leaving Vader to die , Kenobi retreated and took his fallen apprentice ' s lightsaber . Afterwards , Vader ' s new master , Darth Sidious , found his injured apprentice and took him back to the galactic capital of Coruscant , now known as Imperial Center , to be rebuilt ; the suit that Vader donned there would be one that the Dark Lord would wear for the rest of his life . Prelude . During the Clone Wars , the Son lured Anakin Skywalker into the Well of the Dark Side and corrupted him with a premonition of the duel on Mustafar . The duel began after Darth Sidious , as the newly appointed Galactic Emperor Sheev Palpatine , tasked Darth Vader , his new apprentice , with the assassination of the leaders of the Confederacy of Independent Systems on the volcanic Outer Rim planet Mustafar , in order to bring an end to the Clone Wars . Anakin was followed to Mustafar by his wife , Padmé Amidala , whom he wounded after seeing Jedi Master Obi - Wan Kenobi ; Anakin wrongly believed that Amidala had led Kenobi , his former master , to Mustafar in order to kill him . The duel . The duel was lengthy and brutal with neither of the combatants gaining the edge as their abilities countered each other ' s . The duel took place across a Separatist installation on Mustafar , with the two combatants making their way through hallways , conference rooms , and command centers , the last of which led to their inadvertently triggering a meltdown on the facility when their misdirected weapons cut across a control panel . As a result , the facility ' s shielding deactivated and the large stalks overhanging the lava river collapsed when covered with erupting lava . The fight moved onto the lava river — where Mustafarian workers witnessed it , unaware that the Confederacy was defeated as the facility collapsed — before ending on an embankment where Obi - Wan leaped . He begged Vader not to attack , but Vader , in his anger , refused to listen and attacked , to no avail as his left arm and both legs were severed upon attack . Following an impassioned indictment by Kenobi of how Vader , believed to have been the Chosen One , was meant to destroy the Sith instead of joining them , Vader ' s body burst into flames from the intense heat from the lava river , and he was burned alive . Unwilling to murder his defenseless enemy in cold blood , Kenobi took Vader ' s lightsaber and remorsefully left him on the embankment for dead , before leaving the planet with the dying Amidala . Aftermath . Sidious sensed his apprentice ' s struggle from across the galaxy and personally traveled to Mustafar to retrieve him . Sidious then brought Vader back to Imperial Center , where he placed his badly wounded apprentice into a cybernetic suit of armor that would keep him alive for the rest of his life . Kenobi , meanwhile , brought Amidala to Polis Massa , where she died shortly after giving birth to her and Anakin ' s twin s , Luke and Leia . Kenobi delivered Luke to his former apprentice ' s step - brother Owen Lars and his wife Beru on Tatooine and went into exile on the same planet where he would keep watch over him and take on a new name - Ben Kenobi , and would not meet Vader again for several years . Their final living encounter took place on the Death Star , where Vader killed his former master . Years later at the Battle of Endor , Anakin , inspired by his son , found redemption , sacrificing himself by killing Sidious and rejoining Kenobi in the Force . Behind the scenes . The duel on Mustafar appears in the 2005 film as the climactic battle of the film .