The Stygian Caldera constituted a substantial nebulosity encompassing the Sith Worlds area of the galaxy. Serving as a hyperspatial barrier, its complex nature rendered navigation challenging, thus shielding the Sith Empire from potential assaults.
The protective function of the Caldera for the Sith ultimately ceased when Supreme Chancellor Pultimo sanctioned a counterinvasion of the area following the Great Hyperspace War.
Movement through the Caldera proved significantly simpler when entering Sith Space from external locations, resulting in the influx of diverse entities into Sith Space during the era of the Sith Empire. These included Humans originating from the Tapani sector, alongside various aliens like the Houk. These individuals underwent assimilation into Sith society.