Star Wars 9 includes a big fight between Rey and Kylo Ren, so let's look at exactly where it's taking place. The Star Wars: The Rise of Skywalker trailer from D23 Expo 2019 has been officially released by Disney, meaning fans can have a proper look at the apparent Dark Side version of Rey, and an epic lightsaber duel between her and Kylo Ren.
The battle between Rey and Kylo is something that's been hinted at for a while, with promo photos teasing a watery clash between the two foes-turned-friends-turned-foes, which was then made the centerpiece of the new Star Wars 9 poster too. The new Star Wars: The Rise of Skywalker footage shows us that battle, with a few seconds of action being included towards the end of the trailer, and it also confirms the location of the fight.
In Star Wars: The Rise of Skywalker, Rey & Kylo Ren are fighting atop the wreckage of the Death Star II, which was shown in the first teaser trailer for Star Wars 9 back in April. With the water crashing all around them as they stand on old, slightly rusted ruins, it's quite clearly the same location we saw Rey and co visiting in the initial Star Wars 9 trailer. The water is the same, and the wreckage they're fighting on very much fits with the second Death Star.
The Death Star II in Star Wars 9's debut trailer was seen from the shore, and while this puts us right in the midst of it, the outline in the background matches with what Rey, Poe et al see there, as does the swirling sea of Endor. It's a hugely evocative location, and makes a lot of sense for the setting of this duel: whether it's Darth Vader vs Obi-Wan Kenobi, or Darth Vader vs Luke Skywalker (with Palpatine watching on), the two Death Stars have been the locations of some of Star Wars' greatest lightsaber battles.
The fact that both Rey and Kylo Ren - and as an extrapolation of that, the Resistance and the First Order - have found their way to the wreckage of the second Death Star confirms its importance to the plot of Star Wars 9. There have been rumors of a MacGuffin being searched for by both sides, which could mean it's here - and why they're fighting - but it's also likely tied to the return of Emperor Palpatine, since that was where he died (or so we thought).
It's as the fight between Rey and Kylo Ren happens that we hear Palpatine's voice in the Star Wars: The Rise of Skywalker footage, saying: "Your journey nears its end." Of course, that's tied into the entire conclusion of the Skywalker Saga, but since the fight is followed by the shot of Dark Side Rey with a double-bladed red lightsaber, it also further hints at Palpatine's influence over everything in Star Wars 9, and he might well be the reason Rey and Kylo are having a lightsaber duel.