George Lucas' plans for the Star Wars sequel trilogy included the existence of Sith Force ghosts, a concept that is now part of the franchise's canon. Prior to Disney's acquisition of Lucasfilm, Lucas had outlined his ideas for a continuation of the Star Wars saga after Return of the Jedi. While Disney incorporated some of these ideas into their three-movie sequel storyline, it is evident that Lucas' vision would have diverged significantly from what was eventually produced.
One notable aspect of Lucas' plans for the Star Wars sequel trilogy involved the inclusion of Sith Force ghosts, as revealed in The Art of Star Wars: The Last Jedi by Phil Szostak. This book featured concept art from Lucas' original designs, created before Disney's involvement in the sequels. The artwork depicts an aged Luke Skywalker in exile, accompanied by a Sith Force ghost. Christian Alzmann, the senior art director of Industrial Light & Magic, provided accompanying text explaining this artistic interpretation.
The idea of Sith Force ghosts was mentioned in The Art of Star Wars: The Last Jedi, as it shared similar plot elements. The concept of Luke going into exile, which was initially part of Lucas' sequel plans, involved hiding at the first Jedi Temple. Although Lucas intended for Sith Force ghosts to be included, Johnson may have used the concept art as inspiration for an older, exiled Luke Skywalker.
How Sith Force Ghosts Fit Into Star Wars Canon
Unlike the Jedi, who are able to manifest themselves in a spiritual form in the physical world (examples being Yoda, Qui-Gon Jinn, Obi-Wan Kenobi, Anakin Skywalker, Luke Skywalker, and Leia Organa), the Star Wars sequels did not introduce the concept of Sith Force ghosts. However, the idea of Sith spirits does exist in other forms within the Star Wars canon, including in one of the sequel films. Sith spirits, unlike Jedi, are more closely linked to specific objects or locations. This distinction was evident in Star Wars: The Rise of Skywalker, where Emperor Palpatine makes his return, marking a departure from Lucas' original plans for the Star Wars sequels that Disney implemented.
Palpatine's will was preserved by connecting his spirit to the planet of Exegol, resulting in a strong Sith presence on the planet, including Palpatine's clones and the Sith Eternal. Unlike Jedi Force ghosts, Sith spirits can exist in the Star Wars universe. It remains to be seen if a traditional Sith Force ghost will appear in a future Star Wars installment, as originally intended by George Lucas.