King of the Black Covenant
In frostbog, where the shoreline shifts like the ever changing dunes of the southern sands, one island stands alone as an unchanging sanctuary from the bitter cold, beast, wind and wave. At least it used to. Long ago, but not so long that it's been lost from memory, a mad witch king took this fair isle as his own, and performed twisted and depraved experiments on his subjects, aiming to find the key to immortality, and then after, to achieve ultimate power. The gods watched his experiments and were intrigued. Those gods of good sent Angels down to stop the monster before he could achieve his goal. Those gods of evil sent demons from the pits of the earth to gain the power of his creations, so he captured them all, he took bodies from the graves, captured treants and fey, hunted down mindflayers and dragons, killed angels and demons alike and mixed them with the flesh of Human, Elf, Lizardfolk, and the like. And then, the men of the sanctuary fled, and banded with the barbarian tribes from around the still isle. This unlikely alliance, forged from necessity, the bonding of angels and demons, and even his own creations as one waged war against the Mad King and his few, but powerful allies. The war was unrelenting for several months. There was no room for weariness or rest, as the enemy didn't rest or let up. Raining death upon the legions of angels, demons, dragons, experiments, common people, and everyone else pushing back against him, the Mad King and his allies brought Hell to the material plain. However, as few as his numbers were, he was bound to fall. After months of seemingly endless casualties, the last of his allies still in the fight was at last slain. In the face of his own defeat, rather than face death which he feared so much, he fled to the bowels of his castle, locking himself in the dungeons and both physically and magically fortifying his defenses. There he stayed, where he is believed to have eventually rotted away. With the threat gone, the ruined citadel of the still isle had nothing left to do but rebuild, and the barbarian tribes sunk back into their hovel camps, and the angels and demons went back from whence they came.
That was 200 years ago. Now, something irksome is stirring in the bowels of the castle, fires burning from the tallest tower, men and women vanishing, some turning up dead, others, not turning up at all. Strange sightings from wolves to strange men in cloaks begin to crop up. Earthquakes shake the land as the sanctuary isle awakens. The mad king isn't gone at all, at least, not his legacy.