Byss is a planet located deep in the Core of the fictional Star Wars galaxy.

Shortly after the emperor had fallen, Luke Skywalker was captured by the Empire and brought here to serve a clone of the emperor. Leia, Han Solo, and some of Han's old friends went there to bring back Luke to their side, but they learned that he hadn't left the Rebel Alliance at all. He was trying to learn about the Dark Side, and why his father went over to it, but he did give his droid, R2-D2, the plans to the Empire's latest weapon called the World Devastator. The planet was later destroyed by the Galaxy Gun, however it still served as a strong Dark Side focus point across the galaxy.