The Tower of Adacius
by Matthew FleetLocation, Brun - 65W, 57N - The lands affected by the description below form a 20 mile radius centered on Adacius's tower
Adacius was a Thyatian mage, with an impressive knowledge of planar and dimensional lore. But as often is the case, knowledge was not enough to fulfil his desires, which could only be satiated through power.
Adacius chose to live in a distant land to the North West of what was then a remote Thyatian Colony, and to the North of a region where the dead did not sleep. He built an impressive tower by commanding earth elementals to do his bidding, and there, he studied forbidden magics that were outlawed in most lands ruled by men. He mastered a spell which allowed him to summon Malferas from the Dimension of Nightmares and bend them to his will. He summoned and controlled a number of these demons, but it was not enough. His final goal then became to summon and control a Greater Malfera. This would give him true power, and true knowledge, or so he thought.
A Greater Malfera named Idal'ysial was finally summoned, but it resisted Adacius's efforts of mental control, and Adacius was slain in the ensuing battle. Idal'ysial then saw potential in its new surroundings, and kept the gate open between the Dimension of Nightmares and Mystara. Idal'ysial realised that it was possible to expand almost unopposed in the nearby surrounding lands, unlike its home plane, where it fought a battle without end against others of its kind - this had always been the way of things.
In the following years, Idal'ysial turned the surrounding countryside into something more similar to that of its home dimension, and had a number of its minions settle in and around Adacius's tower. These lands now have a crimson sky during the day, and a crimson moon at night. Carnivorous plants twist towards the sky and wait for prey to come within reach, not that much can survive the poisonous atmosphere surrounding the tower, where reddish vapours twist and turn in the air like venomous snakes. Giant bat like creatures fly high in the red sky, while Malfera and other dread creatures walk the ground both day and night, giving no respite to those unfortunate enough to wander into these cursed lands. And in the middle of this unforgiving territory stands a black tower of obsidian and granite, pointing skyward like a dark finger - a permanent testimony to the folly of its deceased architect, Adacius.
But just as knowledge was not enough for Adacius, so it will not be for others. For there are those that will not be content to merely know that there are powerful summoning magics stored away at Adacius's tower, and will be compelled to obtain them. There will also be those who will not be content to merely know that evil walks the land around Adacius's tower, and will be compelled to destroy it, together with the gate that enabled this to occur.
Unbeknownst to Idal'ysial, it will have to struggle without end to maintain its dominion around Adacius's tower. This will always be the way of things.