Apostae

Title Dungeon Planet
Location Pact World
Apostae is a hollow planetoid with no atmosphere and few resources. Mysterious gateways on the planet's rocky surface access a network of tunnels, magitech chambers, and caverns inside its core. The world itself is an immense complex or world ship that was sent to the Pact System in ages past. Azrinaran elves escaped lost Golarion through a portal that transported them inside Apostae. Eventually they found their way to the surface, where their descendants established wealthy dynasties that control Apostae's industry in modern times, specializing in magitech, weapons, and illicit commerce.
Regions include Nightarch, a pressurized megacity where opulent spires tower over air-choked slums, named for the massive gate leading inside the planet at the center of the settlement; the Silted Sea, an expanse of dust infested with undead; Orobor Abyss, a deep surface crevice crawling with bizarre life-forms; Mehel Gorge, a canyon network used for corporate testing and military training; and the Empty Lands, cavernous halls deep beneath the planet's inner corridors that are large enough to fly a starship through.