From The Hollywood Reporter:
“Star Wars: The Rise of Skywalker’s final trailer has been revealed, and it looks to close the three-film, 40-year Skywalker Saga. Given the title, the Skywalker bloodline will have a crucial role to play. […] This leaves the role of the Anakin Skywalker still unclear. The character has had important roles in both the original trilogy and the prequel trilogy. His mask still serves as a symbol for grandson Kylo Ren. As the first Skywalker and original chosen one, what role does Abrams envision for him?
Anakin’s role in Star Wars is likely the most important across all sagas when put into proper context. In the Age of Rebellion, fans were introduced to Anakin through Darth Vader. […] Sixteen years later, George Lucas returned to Star Wars with Star Wars: The Phantom Menace. While the trilogy was divisive among longtime fans, there is an entire generation that grew up with this set of films as their first interaction with Star Wars. For many, Anakin Skywalker is Hayden Christensen’s portrayal before he is Darth Vader. It is this generation of fans who are now in their 20s, eagerly hoping that Star Wars: The Rise of Skywalker will give respect to their era of Star Wars as much as it does the original trilogy.
Plot-wise, there are many ways to have Anakin Skywalker’s presence felt in The Rise of Skywalker. The first is to affirm his place as the Chosen One, the one who can bring balance to the Force. For a while, Anakin was well on his way to fulfilling it. His time training with Obi-Wan Kenobi (Ewan McGregor) and becoming one of the leading generals during The Clone Wars series proved his valor. He was manipulated and turned to the dark side by Palpatine (Ian McDiarmid), mostly due to the fear of losing Padme (Natalie Portman). After defeating him on Mustafar, Kenobi cried for his fallen brother, yet Anakin’s story did not end there and his destiny as the Chosen One was not truly lost. Anakin Skywalker ended up fulfilling his destiny when he killed the Emperor and redeemed himself in the eyes of his son. This makes Emperor Palpatine’s role in The Rise of Skywalker that much more interesting. His rebirth in the Sequel Trilogy should not take away from Anakin’s actions in The Return of the Jedi, so there must be more left to his story that Abrams wants to tie together.
While the Age of Resistance is essentially the story of Rey and Kylo Ren, Abrams has stated on numerous occasions that Star Wars: The Rise of Skywalker will be giving respect to all three eras of Star Wars. This is evident by Emperor Palpatine’s return as the primary villain of the film, reaffirming his place as the one true evil across all three sagas. While Anakin and Luke Skywalker should both have a role in the defeat of Palpatine again, it will likely be Rey or Kylo who win the day.
So how can Anakin Skywalker return in The Rise of Skywalker without overshadowing the other characters? One idea is for a fan-servicey Avengers: Endgame style showdown. Rey has been trained by Luke Skywalker and his Force Ghost is likely going to be assisting Rey in some fashion. Kylo Ren takes great influence from his grandfather, just the wrong side of him. The concept of both original Skywalkers appearing as Force Ghosts in the final battle against Palpatine could leave most fans satisfied. Still, Star Wars is known to be a bit subtler than Marvel and there might be more subdued ways to make Anakin Skywalker work.
Concept images for Star Wars: The Force Awakens suggest Anakin Skywalker was going to have a brief appearance as a distorted Force Ghost. [Note: it was just an idea from a concept artist, it wasn’t in a rough script] It was unclear what role the ghost would have had before the idea was scrapped but it did feature Hayden Christensen as an Anakin-Vader hybrid Force ghost, likely to influence Kylo Ren in some way. Exploring this concept further could lead to a moment where Anakin speaks to Kylo Ren, explaining the errors of his own past and the path to redemption that is still possible. […]
For viewers who grew up with the prequels, whose first connection to Anakin Skywalker was as a Jedi, not as Vader, having Hayden Christensen return in The Rise of Skywalker would be just as poignant as when original trilogy fans saw Mark Hamill’s old Luke Skywalker in the final shots of The Force Awakens. To be a true finale of the Skywalker Saga, Star Wars: The Rise of Skywalker needs Anakin Skywalker to have some role in the film. Whether that role is a full appearance or just a symbolic one, it is safe to say that Abrams has something in mind to leave the legacy of Star Wars in a good place.”