"THE DEAD SPEAK!" declared the opening crawl to the final film in the Star Wars Skywalker Saga, Episode IX: The Rise of Skywalker. While it certainly made some dramatic sense to have Emperor Palpatine, the Sith Lord Darth Sidious, return to conclude the story he began, his rise from the dead was … not really that well explained. Even Poe Dameron himself just said, "Somehow, Palpatine returned!" and left it at that. Those (like me) who were invested in the previously-canonical Star Wars expanded universe assumed there was some clone play at hand, a la 1995's Dark Empire story. Others (like my wife) were left scratching their heads at a confoundingly lazy hand-wave of a plot line.
A year and a half after the movie's release, Lucasfilm Story Group member Emily Shkoukani has finally published an official explanation of WTF happened with Palpatine on the StarWars.com Inside Intel Blog. Titled "Palpatine's Contingency Plans," the blog post traces through-line from Chuck Wendig's Star Wars: Aftermath novel trilogy and across the sequel trilogy (with a brief nod to The Mandalorian), in an attempt to make explicit what was plainly absent from the actual text.
For many years prior to his demise, Palpatine sought immortality on the Sith planet of Exegol. It was on this planet that he and his cultists, known as the Sith Eternal, experimented with cloning. Exegol was also where Palpatine built his Final Order fleet. As an immortal Sith, Palpatine would reign supreme over the galaxy with his Sith armada. This would be the grand finale of the Contingency, known only to a select few.
When Palpatine was killed on the second Death Star, his consciousness transferred to a clone of his own body on Exegol but the body was too weak to contain him. This led to Palpatine creating more clones and strand-casts of himself in the hopes that one would offer a more suitable vessel for him to inhabit. All of this effort ultimately culminated in Rey, the daughter of one of Palpatine's strand-casts. She was the perfect vessel — but her father and mother did everything they could to hide her from her sinister grandfather.
It's no "Have you heard the tale of Darth Plagueis the Wise?" but it's better late than never, I guess. Although it does leave me wondering why he didn't have a contingency for his contingency…
Star Wars Inside Intel: Palpatine's Contingency Plan [Emily Shkoukani / StarWars.com]