Luke Skywalker did appear in Star Wars: The Force Awakens but only for a few minutes during the final scene, but we still have no idea what the Jedi has been up to in the years following Return of The Jedi. So it goes without saying that when The Last Jedi drops next week the Jedi will be a much different person than the hero we left on Endor. One thing that we do know about his past is the fact that his nephew, Ben Solo (Kylo Ren) walked away from his Jedi training after being seduced by the Dark Side. But actor Mark Hamill came up with his own depressing backstory for Luke that involves a dead wife and child to help him get into the mindset of this older and broken Luke for his role in The Last Jedi. In a recent interview with EW Hamill summarized:
"He left the Jedi to raise this young child and marry this woman. And the child got hold of a lightsaber and accidentally killed himself."
It needs to be explained that this backstory is not part of the canon, Hamill merely used it as a tool so that he could effectively portray a darker Luke Skywalker who experienced a lot of tragedy in the decades between Return of the Jedi and The Force Awakens. Hamill explains that because of their son's tragic death, Luke returned to his Jedi life, which set him on the path to his Jedi academy being destroyed and him deciding to go into exile on Ahch-To. As for why Hamill chose this particular backstory, here's what the actor said:
"It's nothing to do with the story, but when I think about gun violence and you read these tragic stories of kids getting hold of their parents' guns and killing a sibling or themselves, I mean, I had to go to really dark places to get where Luke needed to be for this story."
Hamill also tested out his backstory ideas with The Last Jedi director Rian Johnson to confirm that the emotions he was channeling as a result of his story didn't conflict with anything that was actually going to be used in the movie. So even though the story was something Hamill was using to enhance his performance, audiences will still see a guilt-ridden Luke in The Last Jedi who's so haunted by what's happened to him, that he's under the impression that it's time for the Jedi to end.
When it comes down to it, Star Wars fans will learn what really happened to Luke in the years before The Force Awakens when The Last Jedi hits theaters on December 15.