Jevicca sits and tells you a story of the city's history.
"In the ancient recesses of time, a powerful and benevolent cleric set upon a well-intentioned plan. In those days, evil was on the decline and the forces of darkness had been routed in almost every field of battle. The master of evil dragons had been chained, and even the fell races of orcs and goblins, once more numerous than the races of humans, dwarves, elves, halflings, or gnomes - had squirmed back into their meager, shadowy refuges.
With malevolence on the wane, the cleric Danar Rotansin sought once and for all to ride the world of the remaining evil influences. This powerful figure began to gather up all the evil artifacts, objects of dark power, trapped essences of vanquished fiends, demonic relics, and even the last vestiges of particularly horrible diseases. Danar called all of these things "banes" and imprisoned them. He believed that, if destroyed, the banes would simply release their evil into the world to wreak more havoc and bring about other darknesses. Destroying banes begat new banes.
Danar used powerful spells and magic items to accomplish his task, working tirelessly. As his collection of banes grew he began to bury them beneath his tower, Mosul Pearl, located near the sea. Danar constructed a vast catacomb, well warded and sealed, deep underground, and he called it the Banewarrens. He also found allies who believed in his cause to aid him. Chief among them were the dragon known as Saggarintys the Silver King and a celestial named Bastion, Guardian of the Morning.
But Danar's goal was folly. Concentrating so much raw hatred and despite - so much darkness and evil power - in one place was a terrible mistake. His actions drew the attention of vile intelligences of whose existence Danar had never even dreamed. These secretive forces manipulated events (and perhaps even time and space) to ensure that the Book of Inverted Darkness fell into the hands of this well-meaning cleric.
The Book of Inverted Darkness is an artifact older than the world itself. Scribed by gods and demons, its pages contain vast lore (only the Book of Eldritch Might contains greater lore, it is said). Unfortunately for Danar Rotansin - and the world - the book presented this dreadful knowledge using supernatural techniques, giving it an irresistibly seductive quality.
While he intended to seal the book away with the rest of the banes, Danar lingered over its pages for just one instant too long. Its cunningly crafted words beguiled him to keep the book by his side. Soon, he read more. And more.
And still more.
The book consumed Danar. He neglected his quest to gather the remaining banes. He withdrew from his family and comrades. The book's dark lore corrupted his spirit and twisted his mind. The lure of the dark power and forbidden knowledge was too much, even for Danar. Danar Rotansin became Eslathagos Malkith - the Dread One. With the vast resources of the banes he had gathered and the knowledge he gained from the Book of Inverted Darkness, the Dread One withdrew into his tower, also renamed: Jabel Shammar. He emerged only a few years later, launching an attack so devastating, it threatened to tear the world asunder. His might knew few bounds, and with his magical aid, the armies he created or summoned conquered the surrounding lands with ease.
The earth itself, no longer able to tolerate the concentrated evil that Eslathagos Malkith and the banes represented, thrust Jabel Shammar away from it, creating a tall, impossibly high and narrow spire atop which the tower stood, its former pearly hue turned black as night. From there, the Dread One could survey the world - a world he desired to either conquer or crush entirely.
Only the actions of all the mortal races, led by powerful and stalwart heroes (many of whom had been friends and companions of Danar) stopped the forces of Eslathagos Malkith. It is said they carried the battle into the halls of Jabel Shammar itself. When it was over, the Dread One lay defeated. The world's greatest heroes sprawled dead and dismembered around him. Most of them had lost not only their lives but their souls to their foe's magic and the banes he wielded.
Some bit of Danar - the good and true man he had once been - still remained, however. His spirit, now free of corruption, managed to seal the Banewarrens once again. Although his quest remained uncompleted, and some of the banes were released again when he became Eslathagos Malkith, the warrens still contained vault upon vault of evil artifacts, foul creatures, and vile relics that it keeps away from the world at large.
Unless the Banewarrens should ever become unsealed again."