Iblis Ultima III

Iblis Ultima III is a forbidden Dead World in the Iblis Ultima system, and is the site of the Hell-Vault which has caused the downfall of many worlds in the system. Formerly a prosperous frontier world, the planet is now a dead, airless rock. Inquisitorial spacecraft constantly orbit the planet, ensuring none can approach it.

Before the Exterminatus order decimated all life on its surface, the world was an Ice World dotted with frontier settlements, mines and manafactoria.

The Hell-Vault
Millenia ago during the Great Crusade, the Luna Wolves legion discovered a cache of powerful Xenos technology in this system. The Emperor, who was still at the head of the Crusade at the time, investigated the technology. Shockingly, the technology consisted entirely of Daemon Engines, including the apocalyptically powerful Hellscape Cannon. The Emperor could not destroy the technology at the time, as it would reveal the then-secret existence of Chaos to his legions. Instead he covered it up as dangerous Xenos artefacts, and buried it beneath the surface of an unknown planet in a vast chamber he called the Hell-Vault. This planet is now known as Iblis Ultima III. After the Heresy and the Emperor's interment on the Golden Throne, this became completely forgotten.

Millenia later, in M38, the Iblis Ultima system was colonised by eager and opportunistic Imperial citizens hoping to better their lives and attain wealth. However, the settlements and cities on the first four planets of the system were wracked with mutation, heresy and warp-taint due to their mere proximity to the buried Daemon Engines. The Inquisition ordered Exterminatus on all four planets, and declared the zone forbidden. To enforce these conditions, a small Inquisitorial base was set up on  Ultima Iblis V, which was also declared forbidden. Over the millenia this small base has grown to a considerable size, and is now a stronghold for the Imperial Inquisiton.

Despite the forbidden status of the first five planets of the system, the outer three planets of the system and their moons have a maintained a small but stable population and industry. This is likely due to the trade route passing through the system's outer worlds.

The Night of Horror
The week in which the world of Iblis Ultima III gave in to its chaotic corruption from beneath in the surface is often referred to by the small handful of survivors as the Night of Horror. This is due to the fact that for the entirety of the week, the sky was jet black and lightless.

Little is known about the actual happenings of this week, as most survivors were too traumatised to speak of it. What is known, however, is that it started after a mining complex drilled deep beneath the ground in an area previously without mines. Imperial scholars have speculated that this mine may have reached close to the Hell-Vault's outer walls, and let the corruption loose.

During this week, it is said that daemons of all ranks ran rampant through the world; lesser daemons, greater daemons and even mighty daemon princes poured out of the warp rifts that were opening and closing every second throughout the world. Almost all citizens were mutated, and the few that escaped mutation were mostly killed by the mutants or daemons. Towers of quivering flesh burst from the ground, and apparitions of all shapes and sizes burst from nowhere. The air was constantly alive with deadly storms, storms which bore the faces of tortured sprits in their winds.

Iblis Ultima III was by far the most severely effected by the corruption, and less than an hour after the Night of Horror began its neighbouring worlds also met their downfall. After arriving intially on Iblis Ultima I and failing to put down the chaotic activity with Inquistorial Stormtroopers, Iblis III met its fate with a swift, blunt exterminatus operation.

The inital exterminatus operation, however, failed to destroy some of the corruption. Daemons, mutants and apparitions still managed to rise from the ashes of their world and run rampant through the ruins, looking for victims. When they found none, they turned on each other. Exterminatus orders were carried out daily for several months after this, and it was only after the 134th standard day that the last ember of chaos flickered out. By the time this had happened, Iblis Ultima III was heavily scarred and unstable. The world no longer orbits in a standard fashion, and is now potato-shaped due to extensive scarring.

Moons
Iblis Ultima III once had a small moon, which was home to a mining complex. However the moon was reduced to an asteroid belt surrounding the planet by Inquistorial orbital fire. This asteroid belt, coupled with the orbiting Inquisition spacecraft, keep the planet from ever being visited.