Yahannem

Most people believe in a hell, many believe this is it. With sweltering heat, lava Oceans, scorching tornadoes and unholy geothermal activities, Yahanem  (aka  Yanem  in far Orexi and Pnevma Constellations)  holds 6 uncommon containment facilities, more than 30 miles deep down the thickest parts of the planet's continental plates, most of which are withing the radius of a few hundred miles from the northern pole. Large underground structures, teeming with untold horrors, containing 666,666 of the most menacing individuals, from vogue and remote worlds in all 3 arms of the verse; who have done unspeakable crimes against humana. They are denied the rights to live anywhere else and hence must spend the rest of their eairs within the constructs of the prisons. No one sentenced here has ever left. There was a rebellion by the inmates a few hundred years ago, but the sultan's fleet arrived in the system before they could even take control of the holding facilities.