Stygeon Prime, also known simply as Stygeon, was a mountainous snowy planet located in the Stygeon system of the Outer Rim Territories' Nuiri sector. During the Clone Wars, the Sith Lords Darth Tyranus and Darth Sidious imprisoned Sidious's former apprentice Darth Maul in the Spire, a Confederate prison. Maul was later broken out by Mandalorian forces that were part of the Shadow Collective. After the Clone Wars, the planet was later taken over by the Galactic Empire.