The end of Star Wars: The Empire Strikes Back is one of the most famous moments in film history. People who haven't actually seen it still know of the major movie twist that takes place. It's part of our cultural heritage at this point. But what if those few words from Darth Vader had a very different effect on Luke Skywalker? What if Luke turned to the Dark Side?
We're teased with the idea that Luke Skywalker could fall to the Dark Side from early on in his training with Yoda in The Empire Strikes Back, and the idea that such a thing could happen isn't entirely dispelled until the end of Return of the Jedi. In the end, Luke never seems to seriously contemplate joining Darth Vader, but how would the rest of the trilogy have played out if he had?
What Happened When Luke Skywalker Fought Darth Vader
Luke Skywalker is largely ill-prepared for his battle with Darth Vader at the end of Star Wars: The Empire Strikes Back. Luke's ability with a lightsaber and with the Force are enough to keep him from getting killed, but Vader pretty much owns the battle from start to finish. However, as unprepared as Luke was for the fight, he's even less prepared for what Darth Vader has to say. After losing his hand, Luke learns that Darth Vader is his father, and dad wants his son to stand by his side. Together, says Vader, father and son can rule the galaxy. Luke says he'll never do that, and lets himself fall, and possibly die, rather than join the Dark Side.
What If Luke Had Gone To The Dark Side?
But Luke is alone. He's injured, he's scared and angry, and he does clearly believe that Darth Vader speaks the truth. And perhaps George Lucas could have, if he had felt slightly differently, let Luke make this decision. Now, the main hero of the trilogy becomes its greatest villain. Luke becomes an apprentice to Darth Vader. His friends discover Luke's decision and are scared. The end of Empire is probably what remains of the heroes, with Han Solo frozen and Luke turned, wondering how in the world they can push forward.
When Return of the Jedi opens, Luke and Vader rule the galaxy, having destroyed the Emperor in between movies. He was more presence than character before Jedi anyway, and the duo seem unstoppable. So where does Return of the Jedi go from there?
Leia Is Trained As a Jedi
If Luke Skywalker has turned to the Dark Side then we need a new Jedi hero. Luckily, we're told in The Empire Strikes Back that "there is another." We learn in Return of the Jedi that Luke has a sister in Leia Organa, and that she is therefore, strong in the Force. Assuming that Luke turning bad is the only thing that we're changing in the story, then Leia is still a Skywalker and she needs to be trained. Since Leia never meets Obi-Wan or Yoda in the films, getting this going is a bit complicated, but let's assume that one or the other is able to use the Force to make contact with Leia to begin her training. Maybe it's been happening already during the break between films and her new abilities are revealed to the audience as a surprise during the rescue of Han Solo.
This is something that a lot of Star Wars fans wanted to see anyway and it honestly makes better use of the whole "there is another" tease, as Return of the Jedi basically goes nowhere with it beyond the reveal. This essentially puts Leia in the role that Luke actually played in Return of the Jedi. Her task is to take on her brother and father and defeat them. She, of course, still believes there's some good... in Luke.
Han Solo Leads The Endor Attack Alone
If Luke Skywalker is a villain and Leia has to run off to do battle with Darth Vader and Son, then this leaves Han Solo basically alone to lead the fight on Endor to take down the shield generator. This probably doesn't change a great deal about the events that take place in the battle, but it does potentially mean a very interesting character arc for Han Solo. We know he's a good fighter, but here he'd have to be a good leader, something which doesn't necessarily come as easily to the former smuggler. He would likely struggle with the responsibility, because that has never been his strong suit, but in the end, Leia and the Rebellion are counting on him and he knows what must be done.
Luke Is Redeemed, Darth Vader Isn’t
If Leia is the Jedi hero taking the place of Luke in Return of the Jedi, then the events of this part of the story would likely play out more or less as they did in the film, except that the roles of Darth Vader and the Emperor are replaced with Luke Skywalker and Darth Vader. Leia would, of course, want to reach out to the good in Luke and try to bring him back from the Dark Side. She might even try to reach out to both of them, they are both family, after all. But Leia bringing both of them back from the brink seems like a lot to do narratively speaking. It's a bit too neat dramatically. So I'd expect Leia to eventually get through to Luke, and then the siblings defeat Darth Vader together.
The one other major change I would expect is that Luke doesn't sacrifice himself in the effort. Luke and Leia both survive, and we see final moments of the film play out largely as they did in the movie that we saw.
A Luke Skywalker shift to the Dark Side would have made for a significantly different Return of the Jedi. It would have almost certainly made for a very different sequel trilogy, as all the original trilogy characters would have been in very different places. In the end, I can't really imagine RotJ going this way. I don't want this version of the story. At the same time, it does open up some interesting possibilities that make me feel like this wouldn't have been the worst idea if it had been the one we got.