A large part of Star Wars' decades-long appeal is that it's about families and inheritance, the stuff we get from the people who preceded us. The Last Jedi delivers a poignant and powerful take on what it means to mature when you have to shoulder heavy responsibilities.
In The Last Jedi, Luke Skywalker represents hope. His sister General Leia hopes that Luke will leave his self-imposed exile to rally the Resistance against the fight against the evil First Order. The film opens right after the ending of The Force Awakens and in their first scene together, Rey nervously hands Luke's lightsaber back to the Jedi master. What happens next is surprising: he disdainfully chucks it over his shoulder and walks away without saying a word. That sets the tone for where Luke is at this point in his life. He doesn't want anything to do with being a hero, training Rey, or continuing the legacy of the Jedi in any form.
This bitterness comes from his disastrous past with Kylo Ren. The nephew originally known as Ben Solo was part of a new generation of trainees being mentored by Luke, an endeavour that ends in tragedy when Kylo slaughters classmates and burns down the temple. The galaxy remembers Luke as a legend but he sees himself as a failure, someone who couldn't keep his sister's son away from the Dark Side of the Force. Luke finally relents and agrees to train Rey, and it's affecting to see how, over the arc of four cinematic episodes, he's gone from a wide-eyed boy on Tatooine to cranky old war vet ready to burn sacred texts and end the legacy of the Jedi.
Last Jedi director Rian Johnson cannily homes on the idea of Luke as a symbol. When the first generations of Star Wars fans were young, we all wanted to be Luke, figuring out our powers and roles in life's great tapestry. We thought we could move through hard lessons, shocks and loss and emerge with a surprising balance of resolve and badassery, just like Luke did in Return of the Jedi. The enigmatic ending of The Force Awakens teased us with the idea that Luke might have transcended trauma like he did before and ascended to a higher plane of consciousness. We'd get to see him enter the fray as a mentor, maybe. But Last Jedi delivers the opposite of Luke as wise old teacher. He's bitter about what's happened to his life, rants about how the Jedi legacy is one of failure, hypocrisy and hubris, and views Rey with distrust.
However, Luke does use the symbolic power he's saddled with and it's done in a metatextually subversive way. He walks onto the battlefield and withstands the full onslaught of the First Order's assembled forces. Kylo Ren's hate-filled attacks have no effect on him either. Johnson seems to know that this is the calmly resolute, ultra-powerful Luke Skywalker we've been waiting for. But then it's revealed that he's not really there. While it's still a feat that he's able to project his presence across the galaxy, it's not the kind of involvement most people expected, which makes the turnabout both clever and cruel.
What's great about The Last Jedi is that it engages with the idea of legacies in prickly and complex ways. Luke's narrative arc can be read like a rejection of dogma inside the fiction and, more provocatively, within the fandom. The man generally understood to be the prophesied Chosen One Who Will Balance to the Force is too scarred to teach but still recognises that Rey is too powerful to leave adrift and undirected. The little he does tell her avoids easy platitudes and, when Luke Skywalker dies, the old ways of understanding the Force seemingly die with him. The Force still exists but it's going to be up to the new wielders to figure out what kinds of lives they want to lead.