Oryx's Black Pyramid Stronghold

A multi-tiered stronghold in the Abyss, built and staffed by agents of the Demon Lord  Oryx. Located in a crossroads in the lesser traveled wild lands of the Abyss, the stronghold was built with a close proximity to a nearby Black Pyramid of immense size in mind. The Pyramid itself is perhaps two hours distant from the stronghold, but its matte-black seamless facade dominates the horizon. Because of Oryx's speed in seizing on the unclaimed territory when the Black Pyramid was first uncovered, he alone was able to establish claim over the site and the surrounding territory.
As it is located on the edges of the Abyssal frontier, Oryx only visits the stronghold at most twice a year. In his stead, several of his lieutenants guard the stronghold against attacks from other demons and nightmares borne from the pyramid. Kalavakus, the intelligent vivisectionist, is the strongest of these lieutenants. He was given the position of command as a gift from Oryx for a lengthy service in his army. The lesser lieutenants include the brutish and immense Balban, the blood stalker Sahuagin, and the seductive succubus Kelrose.
Recently, as part of an operation for the Gate Lord Kron, a party of the Fangs invaded the stronghold in a successful attempt to reach a portal to Elysium that had opened up in the dungeon levels of the stronghold. On their way, they defeated the Sahuagin in combat- though they did not manage to slay him- and recruited his apprentice, the Pureblood Demon Callix. Aldis Taenga and Aravae the elf were both slain by a visiting guest from the Abyssal Court, the corpulent Sire Demon Patraavex, who the party encountered mid-coitus with the succubus Kelrose. Sol Ragnar held off of slaying Kelrose after she aided them in killing Patraavex, and in return, the succubus revealed that she was the patron who had given Tay her charms of seduction that allowed her to first escape a life of slavery in the Chaos- and was also using her as a means to harness the sword logic to gain strength in her own right by drawing from the creatures that Tay slew. Sol wished to bring Kelrose with them, but she revealed that- having already willingly drank of Oryx's blood- she was bound to the stronghold and service to Oryx.
Kalavakus and Oryx, absent from the stronghold during the time when the party teleported in, were never encountered.