Mustafar/Legends

In the fictional world portrayed in the film Star Wars Episode III: Revenge of the Sith, Mustafar is a volcanic planet and the last homeworld stronghold base of the Confederacy of Independent Systems.

On it, the characters Obi-Wan Kenobi and Anakin Skywalker engage in a duel after Darth Sidious/Palpatine secretly betrays the rest of the Separatist leadership (which surrendered) there by sending Anakin to kill them, where Anakin suffers severely at the hands of Obi-Wan. Anakin is pushed into the lava. The resulting injuries require his master Palpatine to have much of his anatomy replaced by prosthetics. Following this treatment, he becomes known as Darth Vader.