Somehow, Star Wars: The Rise of Skywalker - and between established canon and the former Emperor's appearance in the movie, there's plenty of evidence to the theory that he returned in a clone body.
Cloning has been a part of the Star Wars franchise since the very first movie, Star Wars: A New Hope, which included a mention of the Clone Wars. The prequel movie Star Wars: Attack of the Clones introduced an army of clone troopers, based on the genetics of bounty hunter Jango Fett, that were created by the Republic to fight the Separatist battle droid army. These clone troopers proved to be instrumental in Palpatine's deadliest plan: each of them was implanted with a chip that, upon receiving Order 66, caused them to turn on the Jedi and slaughter them. Needless to say, clones have long been d with the dark side.
When confronted by Kylo Ren at the start of Star Wars: The Rise of Skywalker, Palpatine tells him that he has died before and that "the dark side of the Force is a pathway to many abilities some consider to be unnatural." While this could interpreted as a deliberately vague allusion to Palpatine somehow using to Force to resurrect himself after he fell into the Death Star II's reactor, the scheming Sith could just as easily have used cloning to orchestrate his return.
Palpatine Used Clones to Survive in the Expanded Universe
If Palptine's return in Star Wars: The Rise of Skywalker feels familiar, it may be because of its striking similarities to the 1992 Expanded Universe comic Dark Empire. Set in a post-Return of the Jedi future where the Imperial forces have risen again, Dark Empire takes Luke Skywalker to a planet called Byss that is "entirely enveloped in the power of the dark side" - much like Exegol. There, he meets a resurrected Emperor Palpatine, whose dialogue (pictured above) closely mirrors Palpatine's words to Kylo Ren in Rise of Skywalker. Unlike the movie version, however, this Palpatine goes on to explain exactly how he was able to return to life, and reveals that it's not the first time he's done so. The great power of the Force takes a terrible toll on the fragile flesh of Palpatine's body, forcing him to periodically transfer himself into a new clone. This conveniently explains how a villain as arrogant as Palpatine might have had a new clone body ready to go in the event of his death.
Star Wars Canon Sets Up Palpatine Transferring to New Bodies
A great deal of Star Wars canon was discarded when the Expanded Universe was retconned out of official continuity and rebranded as Star Wars Legends in April 2014. However, one of the Rick and Morty). Cylo ultimately ends up turning on the Emperor and is killed for his betrayal, but this story establishes that Palpatine knew about a method of surviving death by setting up a clone body to be activated in the event of his defeat. Palpatine being ever the schemer, it makes sense that he would have stolen Cylo's idea and created his own clones in order to achieve immortality.
The Rise of Skywalker Confirms Palpatine Was Making Clones
When the sequel trilogy first began with Star Wars: The Last Jedi, and at the start of Rise of Skywalker Palpatine reveals that the so-called "Supreme Leader" was merely a clone - a puppet designed to exert Palpatine's influence without revealing his continued existence. We even see some spare Snoke clones growing in a vat on Exegol, which means that Palpatine had cloning technology readily available to him. If he used this technology to create Snoke, it stands to reason that he may have also used cloning to survive his fall into the Death Star II's reactor.
Palpatine's Body Didn't Look Like it Survived the Death Star II Explosion
When we meet Palpatine again in Star Wars: The Rise of Skywalker, he ittedly looks a bit worse for wear. A zombie-like being suspended from a mechanical throne, Palpatine's body appears to be little more than a shell. That being said, the shell doesn't look like it fell down into a reactor and then exploded, which is what happened to Palpatine at the end of Return of the Jedi. One thing seems to be certain: whatever body Palpatine is using in Rise of Skywalker, it's not the same one that fought Darth Vader on the Death Star II.
While it's possible that Palpatine may have used the "unnatural abilities" of the dark side of the Force to build a new vessel for his vile soul, the clone explanation is a lot simpler and in line with what we've previously seen in the franchise. In fact, the two explanations aren't mutually exclusive, as Palpatine may have used the science of cloning in conjunction with his Force powers. Cylo used cybernetics to give himself a simple personality map and backup memories banks, which is what allowed him to transfer his mind between bodies. Palpatine, whose mind is infinitely more complex, is more likely to have achieved the transition using the Force rather than trying to reduce himself down to cybernetics.
What this means for the future of Star Wars is that Disney could very easily find a way to resurrect Palpatine again down the line - though given the generally poor reception to dredging up Palpatine for The Rise of Skywalker, the studio probably won't play that card again for a while.
