Among the Easter eggs hidden in Rogue One: A Star Wars Story is a nod to one Ralph McQuarrie’s original Empire Strikes Back sketches that had Darth Vader living in an evil castle. The Sith Lord’s fortress on Mustafar was imposing even if you didn’t know the backstory, but Star Wars has always been good at giving the hardcore fans a little something extra to prove they see us.

Unfortunately, audiences didn’t get much time to poke around Vader’s angst-filled vacation home. Rogue One had a story to tell, and Anakin Skywalker’s motivations for building a giant tower on the planet where his life fell apart wasn’t one of them. Based on what is known about the Dark Side, you could deduce it was merely the place that filled Vader with the most rage and therefore an ideal spot to charge up his powers. While that may be true, there are also other reasons for the decision to include the castle in Rogue One and why Lucasfilm chose Mustafar as the location.

Recently I spoke to Lucasfilm VP and Executive Creative Director Doug Chiang about his team’s work on the Rogue One concept art. Chiang has spoken before at length about the design for Darth Vader’s castle in the film, but ahead of Rogue One’s home video release, he showed a crack in the usually impenetrable wall that protects future Star Wars installments from prying eyes.

The proto-spoiler came out of nowhere during a conversation about why Vader chose Mustafar as his home base. As I mentioned above, my assumption was the planet fed his hate, the necessary fuel to power Dark Side abilities. Chiang’s explanation was even better than that though:

“It’s interesting, we did a lot of history exploration. Why did Vader build his castle here? Why does it look the way it does? Why does he even come here? For us, it was really figuring out that Vader built his castle on an existing structure, which was this ancient lava dam. And he built it here for a very specific reason. It was to come back here to meditate, to rejuvenate, to reconnect with himself. And it became a very spiritual place, and it was all centered around his bacta tank. And that’s where the form language all built around there. And we’ve done quite a bit of exploration of what’s on the inside of it as well, and hopefully that’ll be seen in some other film.”

Did you catch it? Chiang was just meandering along with an in-depth explanation for Vader’s reasoning when suddenly, we know the Mustafar castle wasn’t a one-and-done for Lucasfilm. Interiors have been designed that we haven’t seen yet. Yes, Chiang hedges with “hopefully” but once he mentioned it, it makes sense. Something as large and important to the Skywalker legacy can’t be ignored, whether by Luke Skywalker himself or Vader’s biggest fan: his grandson Kylo Ren. Perhaps Ben visited Pop-Pop’s castle to snag some sick swag. Maybe Kylo Ren also lives there, in the shadow of the man he venerates. Maybe he put up a “No Gurlz Allowed” sign to keep Rey out. Or maybe Rey or the Resistance will have to enter the remains of Vader’s stronghold for reasons unknown.

Regardless, keep your eyes peeled this Christmas. Perhaps The Last Jedi will give us another glimpse into the heart of Vader’s castle. And watch this space for more tidbits from Chiang tomorrow.