The Forgotten Prophecy
A forgotten moment from Star Wars: The Clone Wars fulfills George Lucas' original wish by hinting that Leia is the real Chosen One of the Force. Since the prequel era, Star Wars' Chosen One prophecy became a huge deal concerning the overall story of the Skywalker Saga. By the end of the original trilogy, it became clear that Anakin Skywalker was the Chosen One as he eventually defeated Palpatine in Return of the Jedi.
Star Wars Force Priestesses
Many have been expecting upcoming Star Wars movies to explore this further given that one centers on Rey Skywalker whose connection to the Chosen One via Luke could warrant discussions about Anakin's past. However, while Star Wars' future explorations of the Chosen One could be interesting, the ways in which the franchise has already done so remain equally compelling. The timeline of Star Wars: The Clone Wars included a great deal of Chosen One elements thanks to the focus the show placed on Anakin. That said, one element of Star Wars lore found in The Clone Wars hinted that Leia was the Chosen One as Lucas had always intended.
The Forgotten Prophecy
Yoda's Vision and the Other Skywalker
In Star Wars: The Clone Wars season 6, one of the arcs centers on Yoda discovering how to manifest as a Force ghost after death. This arc took Yoda on an incredibly spiritual journey as he connected with the Cosmic Force of the Star Wars galaxy, from visions of Darth Bane to Force priestesses. At one point in this arc, Yoda is told something he does not understand by the Force priestesses. The mysterious figures say 'There is another Skywalker' as a baby is heard crying.
Leia_canon_Legends
In the context of Star Wars: The Clone Wars' story, this indicates that the mantle of the Chosen One will move from Anakin to another Skywalker. Throughout the prequels, the Jedi Order assumed that it was Anakin who was the Chosen One. However, this confirms to Yoda that there is another Skywalker that the prophecy could apply to. Many familiar with the Star Wars' franchise assumed this referred to Luke, though this may not be the case.
Poe Dameron sitting by Leia's covered corpse in Star Wars: The Rise of Skywalker
The intentional mirroring of Yoda's words with the priestesses' proclamation that 'There is another Skywalker' means that the latter were speaking about Leia's potential, not that of Luke Skywalker.
Princess Leia death in Star Wars Rise of Skywalker
George Lucas's Vision for Leia
The intentional mirroring of Yoda's words about Leia from The Empire Strikes Back aside, another aspect that supports the idea that the priestesses were talking about Leia stems from Lucas himself. It has long been known that George Lucas initially had plans for nine Skywalker Saga films at different points in his development of Star Wars. Since 2012 and Disney's acquisition of Lucasfilm, Lucas has often spoken about what his plans for the sequel trilogy were before Disney opted for a different direction.
Ben Solo crying in The Rise of Skywalker next to Han Solo from The Force Awakens
Lucas intended to bring back Darth Maul, having the former Sith Lord attempt to fill the power vacuum that was left in the wake of Palpatine's defeat. One of the plans from Lucas was to make Leia the unequivocal Chosen One of the Force, taking the mantle from her father and truly returning balance to the Star Wars franchise. Lucas' sequel trilogy outline was certainly interesting, with the return of a fan-favorite character serving as the main villain of Lucas' Episodes VII, VIII, and IX. Lucas intended to bring back Darth Maul, having the former Sith Lord attempt to fill the power vacuum that was left in the wake of Palpatine's defeat.
Rey and Ben Solo wielding their blue lightsabers in Star Wars: The Rise of Skywalker
At the same time as Maul's resurgence, Leia's importance would grow. Lucas intended to have Leia become the Supreme Chancellor of the New Republic, attempting to reorganize the galaxy into a stable condition while marshaling the fight against Maul and his forces. This would have led to Leia defeating Maul and solidifying the New Republic as a stable, healthy democracy, thus returning true balance to the Force and confirming her status as the Chosen One.
Leia Organa in Star Wars Sequel Trilogy