Luke Skywalker reveals in Star Wars: The Rise of Skywalker that he and his sister, Leia Organa, already knew Rey was a Palpatine, but just when and how did they learn this? Rey's parentage was one of the biggest mysteries of Disney's Star Wars sequel trilogy. While Star Wars: The Force Awakens only teased her origins, its follow-up, Star Wars: The Last Jedi, revealed that her parents were nobodies. Somewhat going against that, The Rise of Skywalker revealed Rey to be a Palpatine, the granddaughter of the Emperor who had somehow returned in the film.

While Rey was understandably disturbed by the idea of being descended from the biggest villain in the galaxy, her masters were not. When she fled to Ahch-To in the hope of living in exile as Luke himself once did, her former Jedi Master appeared as a Force Ghost. There, he revealed that he and Leia both knew who Rey truly was, but that they believed in her strength, heart, and goodness, giving her the encouragement to go on and defeat the Emperor, which she did in The Rise of Skywalker's final battle.

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While that served to drive the plot and Rey's character arc, it did leave behind a big question of just how Luke was able to learn Rey was a Palpatine, and when exactly he did so. As with many things from The Rise of Skywalker, it's a question not yet answered, but there are a few possibilities. When Luke begins training Rey in The Last Jedi, he notes that he has only seen such raw strength once before, while she herself heads straight to the dark side cave when channeling the Force. That was at least a possible hint at Rey being a Palpatine, but it could have been the moment Luke learned the truth. While the power he referred to was Ben Solo, it's also true that Kylo Ren was being manipulated by Palpatine from a young age, and it's been hinted that when Luke turned on his nephew, it was actually Palpatine he sensed. If he recognized the same signs here, then it's possible he realized Rey was a Palpatine at this point.

Luke teaches Rey about the Force in Star Wars The Last Jedi

Another possible explanation is that Luke discovered Rey was a Palpatine after he became one with the Force. With the time afforded to him and being so attuned with the Force, then it's possible Luke could have used this to discover the knowledge of Rey's parentage. In the novelization of Star Wars: Episode III - Revenge of the Sith, Yoda muses with the Force Ghost of Qui-Gon Jinn that "infinite knowledge" would require "infinite time," suggesting that a Force Ghost could acquire such. While there wasn't infinite time between The Last Jedi and The Rise of Skywalker, it's nonetheless plausible that Luke could have learned the truth after his death. In either of these scenarios, it's then likely that his Force Ghost would have told Leia the truth sometime prior to The Rise of Skywalker.

A third option for how and when Luke learned Rey was a Palpatine comes much earlier than the pair's meeting. As revealed in The Rise of Skywalker, Luke and Lando Calrissian spent some time hunting Ochi of Bestoon, an assassin who worked for the Emperor. Curiously, this took place in 21ABY, which is shortly after Rey was left on Jakku and her parents were killed by Ochi. So with Ochi's murder of Rey's parents catching the attention of Luke, then could it be here Luke learned of the existence of a child of Palpatine descent? It's a compelling option, and looking at Disney's approach to canon, arguably the most likely, if only in the sense that it's the one best suited to being fleshed out in a tie-in book, comic, or similar.

This would give greater synergy between the events of the past and the present, tying Rey to Luke in ways not previously revealed. At the same time, though, this would risk making Luke's exile even worse, knowing that Palpatine had a granddaughter and thus, presumably, was still very much alive (something he had already begun to sense). If Luke knew all of that, then leaving without exploring it further doesn't seem like an option, albeit it's hard to overstate the impact his brief turn against Ben was. Because of that, then the notion of Luke learning Rey was a Palpatine after becoming one with the Force is perhaps the easiest and cleanest option, since it explains why he never mentioned it until Star Wars: The Rise of Skywalker, but with enough of a gap for him to explain it to Leia.

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