During the climactic battle of The Force Awakens shows the very beginning of this journey, during which she receives some training from Luke and Leia, but until The Rise of Skywalker, her connection to the ancient Jedi Order remained largely informal.
Although the level of detail their culture is given varies from film to film, the Jedi have always figured prominently in the Rey's pilgrimage to Ahch-To to find Luke Skywalker very much represents how, even after the fall of the oppressive Empire, the ways of the Jedi remain mysterious in the era of the New Republic.
As Palpatine attempts to use his immense power to wipe out the volunteer-augmented Resistance fleet at the end of The Rise of Skywalker, Rey hears the voices of past Jedi reach out to her, lending not only their encouragement but their strength, with which she finally overcomes the revenant Emperor. These Jedi include Yoda, Obi-Wan Kenobi, Ahsoka Tano, and Anakin Skywalker. In speaking with Insider, visual-effects supervisor Roger Guyett commented that the consensus during production was that hearing the voices without seeing their source would give the viewer the sense that "you're with Rey and you're inside her head," making the moment more powerful as well as linking it to the voices that she hears in The Force Awakens.
Making a related point on the presence of Force ghosts in The Rise of Skywalker's final scene, co-screenwriter Chris Terrio voiced concern that explicitly showing too many characters unrelated to the central story might overwhelm viewers. In addition to being simply visually crowded, this large band of Jedi could have been doubly confounding to some audiences because a few of the characters among them, like The Mandalorian likely had not yet been made, which could have resulted in a discrepancy between her portrayals outside of animation.
Ultimately it was probably right that the narrative clarity of the moment outweigh the potential fan gratification of showing these characters as Force ghosts. This is not to mention the fact that, given the amount of relatively high-profile actors involved, it was probably a simple practical necessity to allow them to record only their voice lines without having to agree on a shooting schedule. So while it may overlook an established element of the lore, the restrained way in which The Rise of Skywalker's Jedi voice cameos were handled should by no means undermine the enjoyment to be had in bringing together fan favorites from all nine films and beyond.
The Rise of Skywalker Ruins Last Jedi's Luke/Yoda Force Ghost Scene
