The most recent trailer for Star Wars: The Rise of Skywalker offered several tantalizing hints about where the franchise may head next. Rey and Kylo Ren cutting through the Darth Vader statue was an interesting image of what's to come, but probably the most intriguing stands with Rey meeting what seems to be a bionic Palpatine in a new Sith throne room.
From that shot, director J.J. Abrams seems to be teasing that the Emperor isn't back to his full form. And from what Rian Johnson's The Last Jedi revealed the Force to be, that could mean that Palpatine's true form will only be revealed once Rey and Kylo both die.
In that shot of Rey looking up at Palpatine, clearly a great battle looms as we see what appears to be the ex-Emperor hooked up to a machine in some sort in an image that calls to mind how he turned a charred Anakin Skywalker into the cybernetic killing machine, Darth Vader. However, this also suggests that Palpatine might have to adopt a final form to truly make a comeback and seize power over all the galaxy. What's interesting is that Kylo can't be seen in the shot, which could be an indication that he's dead or otherwise incapacitated by this point. Assuming that Palpatine isn't protecting a Sith-like soldier and potential disciple in Kylo, Palpatine may need him dead, since the Force could give him a shot at his life essence.
In The Last Jedi and even in Marvel's latest Star Wars comics via Luke's arc with Warba, we're getting more and more insight into how the Force acts as the life essence and energy that binds all living things. Seeing as Jedi liked Yoda and ancient Sith Lords lived for many years, the Force could be a repository for immortality -- a fountain of youth, per se. Putting aside the notion of midi-chlorians, it stands to reason that the Force is an elixir of life since it "connects us all," as Luke told Rey on Ahch-To. From what the Palpatine voiceover in the trailer reveals, Kylo and Rey coming together is very important. He needs them united and their coming together in close proximity could make it the trap for the Emperor to drain them.
Assuming he survived the Death Star reactor in Return of the Jedi or somehow lived on through a clone, Palpatine could have retreated to his new base, honing arcane rituals or forbidden science to rejuvenate himself, possibly based on the teachings of Darth Plagueis.
All of this still doesn't explain why Palpatine wants -- or needs-- Rey and Kylo together. Instead of looking to have one of them become his next protege, he could want to use them as a Force battery, so he can feed on their immense combined power like a Sith vampire.
It wouldn't be far-fetched for the film to tweak the Expanded Universe's arc that saw Palpatine using spirit transference to move into other bodies. Likewise, it wouldn't be surprising for these two ultra-powerful figures to be essential in recharging the villain, boosting his energy levels and bringing him back at full-strength.
When Luke says the Force and all the Jedi will be with Rey in the trailer, this also hints at charging up energy levels. This could play a role in the finale if Palpatine tries to drain Rey, leading those Jedi who came before her all syncing up and transfer their energy to her, meaning they're literally with her.
If nothing else, The Last Jedi reiterated that the Force is all around and exists for anyone to use, and Rey's ability to tap into it could be central to Palpatine's plans. A Sith might not be able to unlock this reservoir, which is why Palpatine needs two angry and lost souls. That could've lead him to manipulating Snoke into recruiting Kyle and messing with Rey to drive them both down a path of anger, hatred and darkness.
What's also interesting is if all the past Jedi return to recharge Rey, this could set up cameos from all of the dead Jedi of old, and it could include Kylo's redemption and return as Ben Solo, which has been hinted at throughout the trilogy. This could give the trilogy a fittingly poetic finale that paints both of them as chosen ones and shapes Rey as someone who truly brings balance to the Force as a conduit standing in the middle of the realms of both life and death.
Directed and co-written by J.J. Abrams, Star Wars: The Rise of Skywalker stars Carrie Fisher, Mark Hamill, Adam Driver, Daisy Ridley, John Boyega, Oscar Isaac, Anthony Daniels, Naomi Ackie, Domhnall Gleeson, Richard E. Grant, Lupita Nyong’o, Keri Russell, Joonas Suotamo, Kelly Marie Tran, with Ian McDiarmid and Billy Dee Williams. The film arrives on Dec. 20.