Abrax

All of the world of Abrax exists on the internal surface of a hollow sphere. At the world's center is the iridescent Crystal Sun, which is gravity-repellant and sustains life on the surface around it. Around the Crystal Sun orbits the Nightstone, a massive stone half-sphere that is immune to the Crystal Sun's repulsion and gives Abrax a day-night cycle.   The Crystal Sun shines on a world of danger and secrets. In the forsaken Pale Wastes, mind flayers oversee slaves as they construct a massive structure with an unknown purpose. On the treacherous waters of the Bracelis Ocean, ruthless gangs of pirates search for ships to plunder. In the dark rainforests of Xanqur, yuan-ti dwell in ancient ruins worshipping their malevolent gods.