Warning! Spoilers ahead for Star Wars Adventures: Ghosts of Vader's Castle #1!
Anakin Skywalker might have found redemption and become a Force ghost at the end of Return of the Jedi, but a new Star Wars miniseries by IDW Publishing suggests an evil version of Darth Vader somehow haunted his enemies after his death.
Jedi who achieve the form of a Force ghost have successfully found a way to preserve their consciousness after death and, in turn, retain their identity. As a Force ghost, Anakin's mind therefore persists in this spiritual form, meaning it is undoubtedly Anakin who appears beside Obi-Wan Kenobi and Yoda at the end of Return of the Jedi. But a new development proves there might be more to the story, as revealed in Star Wars Adventures: Ghosts of Vader's Castle #1 by writer Cavan Scott, artists Francesco Francavilla and Megan Levens, colorist Charlie Kirchoff and letterer Shawn Lee.
In the opening scene, Lord Vader's attendant Vaneé is in Vader's castle and clearly speaking to some mysterious voice he refers to as "Master," "Lord" and the much more menacing "the Dark Lord." Vaneé also tells the voice that many people say he was defeated and dead. As the story takes place after the events of Return of the Jedi, the only two people he could be speaking with are either Emperor Palpatine or Darth Vader. Even though Palpatine was cloned and therefore survived the destruction of the second Death Star, it's much more likely that Vaneé is conversing with Vader even though the Sith Lord redeemed himself. In Vaneé's origin story, he became Vader's most fervent lackey on that fateful day he succumbed to madness after being subjected to days' worth of hallucinations caused by the fumes from Mustafar's flames. Vaneé is therefore a creation of Vader and serves only him. The fact that Vaneé later causes a boy named Milo to experience intense nightmares as part of a larger initiative to torture those who wronged "them" further supports the idea that Vaneé is speaking to Vader, as Milo's sister Lina crossed paths with them on Mustafar in Tales From Vader's Castle.
Although not canon, stories in Star Wars Legends tell of Sith Lord spirits finding themselves either bound to an object or location in the living world or forced to persist there due to the extreme malice and hatred they exhibited while they were alive. Could Ghosts of Vader's Castle have canonized this particular detail from Legends? If so, a possibility arises where Anakin Skywalker's evil Darth Vader alter ego somehow split from Anakin's Force ghost and became its own entity, binding itself to his old fortress on Mustafar.
Although this would condemn Vader's spirit to an eternity of restlessness whereby he, like other evil Sith spirits before him, will eventually descend into madness, at least he will be in the company of his must trusted insane lackey, that is, until Vaneé eventually dies, leaving him alone with his memories and hatred. It's an interesting Star Wars theory and presents both the likelihood that Palpatine, too, may suffer the same fate and that a part of every Sith who eventually reforms like Darth Vader did will persist as an evil vengeful ghost, destined to haunt those who wronged them for eternity