The Rise of Skywalker novelization revealed that Emperor Palpatine is a clone. However, how did his consciousness survive after Return of the Jedi? The official novelization was just recently released and it goes into detail how Palpatine was able to keep going after Darth Vader threw him down the Death Star shaft. Star Wars fans were left scratching their heads as to how the villain returned in the first trailer for the movie, and then again after the movie hit theaters.
J.J. Abrams chose to ignore most of how Emperor Palpatine returned in The Rise of Skywalker. There were a few subtle clues, but it is not explained outright. Fans were left to use their imagination and theorize about how it was possible with the clone explanation seeming like the most logical one. We all saw the Death Star blow up with him on it. So yes, he is a clone this time around, but there's more to it. You can read a passage from the book below.
"Plagueis had not acted fast enough in his own moment of death. But Sidious, sensing the flickering light in his apprentice, had been ready for years. So the falling, dying Emperor called on all the dark power of the Force to thrust his consciousness far, far away, to a secret place he had been preparing. His body was dead, an empty vessel, long before it found the bottom of the shaft, and his mind jolted to a new awareness in a new body - a painful one, a temporary one."
There you have it. Palpatine was able to use the Force to thrust his consciousness to Exegol, which was a part of his contingency plan, apparently. So when the Death Star exploded and everybody partied on Endor in Return of the Jedi, Palpatine was Force projecting his consciousness through the galaxy, preparing for his next big plan. He was behind everything in the sequel trilogy, which is something that was explained in The Rise of Skywalker.
Could this have all been explained in The Rise of Skywalker's theatrical release? For some, that is debatable. Other Star Wars fans would have loved to have seen Palpatine's journey on the big screen or at least have it told. If he was supposed to be so important to the story and the overall arc of the sequel trilogy, then yes, it should have been explained a bit better. There was a lot of ground to cover in the movie and J.J. Abrams knew there were some things that were going to have to be left out.
Showing Palpatine use the Force to thrust his consciousness could have proven just how powerful he is, and in turn showed how powerful Rey is at the same time. Having them be related was a whole other bit that some fans took issue with, but that's a story for another time. For now, we can all rest easy knowing exactly what happened to ol' Palps after Return of the Jedi. You can head over Penguin Random House to pre-order the novelization.