This article contains spoilers for Star Wars: Crimson Reign #4.
A new Star Wars comic has revealed the final fate of Palpatine's (and eventually Darth Vader's) heretical Sith mentor. Emperor Palpatine had always been obsessed with the conquest of death. It was an obsession he had inherited from Darth Plagueis, his Sith Master, who had experimented with the technique known as essence transfer. Palpatine killed Plagueis before he could truly master the technique, though, and he would need to continue researching it himself.
Darth Sidious sought the mask of an ancient Sith heretic named Darth Momin. When Momin died, he successfully possessed his mask, transforming it into one of the most dangerous artifacts the Emperor ever acquired. Anyone who wore the mask of Darth Momin would be possessed by his spirit, and the Emperor learned from him before passing it on to Darth Vader; Momin was an architect, and his was the mind behind Darth Vader's temple on Mustafar. He then attempted to use the Force vergence on Mustafar to restore his body, but was defeated by Vader.
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Star Wars: Crimson Reign #4, by Charles Soule and Steven Cummings, finally reveals the final fate of Darth Momin. The comic is set decades after Vader fought Momin, and stars the Knights of Ren, who were assigned to break into Darth Vader's fortress. They chose to break in through the concealed entrance to the Sith shrine beneath the tower, and in so doing they stumbled upon the mask of Darth Momin. It seems Darth Vader simply discarded the mask after his victory, and never even bothered to pick it up. The mask made a desperate attempt to possess one of the Knights of Ren, but they
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