Farplane Bastion

A floating castle-city of winding corridors, great chambers and unspeakable horrors, Farplane Bastion was the home of the Gnosian Brotherhood. Built primarily by the Gnosian Den'shil with help from the entire Brotherhood and the multitude of magical and holy relics they'd collected from all over the world, the Bastion was a floating island fortress of incredible power located outside of normal planar space. The Farplane Nether is a theoretically endless expanse of chaotic energy. Entire universes coming into being momentarily and living out a hundred eons of existence in the blink of an eye before collapsing in on themselves, consciousness appearing in its nebulous clouds only to be snuffed out by the ebb and flow of magic, the Farplane Nether is a truly alien and surreal universe. Only the combined power of the Gnosian living gods could bring even a semblance of order to the madness.

The Farplane Nether is normally inaccessable, even to the most powerful of mages due to the fact that outside of the normal wheel of cosmic inter-planar relationships magic functions differently in unpredictable ways. Den'shil, the Gnosian of Mind and Magic devised and ingenious solution. Using all the power of the Arcantric Ley Stabilizer the Brotherhood stole from Astra de Lunastra and a substantial amount of his own personal energy, he created a bubble of "normal" space inside of the Farplane Nether surrounded by a field made up of a fusion of arcane, psionic and chaotic nether energy. This pocket of pseudo-stable reality inside the infinite abyss of chaos allowed him to construct a vast island fortress from which the Brotherhood could launch assaults on Quesaloth, conduct secret experiments and rest from their journeys.

Inside the Bastion
The group of heroes who descended upon the Bastion were the first non-Gnosians to look upon its corridors for centuries. Most of the castle itself was actually once a part of a massive fortress complex in southwestern Tezren Nerich. It once belonged to a vassal lord named Ulavar Densav, who is believed to be the human man who later became Den'shil the Gnosian. Densav was a highly acclaimed scholar and accomplished mage who was known to his people for his incredible cruelty and tyrannical rule. One day, after nearly three decades of his violent rule, Densav disappeared suddenly and without warning. None of his servants, guards or other attendants knew where he'd gone or why he'd chosen to leave behind all of his things. Rumors spread that he'd been assassinated but were largely ignored by most folk due to the idea that such a hated leader would almost certainly be assassinated in a more public manner, or at least that his body would be displayed with pride by his killer.

About three years after Densav's mysterious disappearance a great catastrophic storm hit the city in which his castle stood. When the storm passed, the castle was gone along with all of its subterranean labyrinthine tunnels and infrastructure leaving a massive gaping crater where it once stood imposingly over the town. There were about fifty people inside the building at the time of the bizarre incident, none of whom were ever heard from again. The incident was investigated thoroughly, but the investigators turned up nothing more than traces of powerful arcane magic. About two years later a village child who'd fallen into the crater while playing at its rim discovered a stone tablet like a bedrock, onto which was inscribed, "What's mine is and will forever be mine."

According to the reports from Malthazaar MacDuncan and the Archmage Arcturus, two of the intrepid souls who aided in the Bastion's destruction, the inside of the Bastion matched almost precisely with the existing floor plans of Densav's castle though its decor and accoutrements had apparently changed substantially. Among the many technological wonders of the place were a number of devices that produced something referred to some as Elemental Revenants. These creatures are little more than raw elemental energy given a semblance of thought and a mental construct onto which the Gnosians painted a rigid command structure ensuring the things could be controlled by any Gnosian with little more than a thought. These devices were churning out so many of the things as to apparently make a legion army numbering in the tens of thousands, presumably to mobilize against Quesaloth or perhaps other worlds.