The Hills of Shade were almost completely ignored by the residents of Faydwer for many years after the destruction of Durathin. Bandits and criminals are likely to have taken refuge there, but such outcasts were far enough from civilization that no real effort was made to discourage this kind of self-imposed exile. Common wisdom across Faydwer held that nothing of importance would ever come of the Hills of Shade.
Of course, nature abhors a vacuum, and such a vast, unregulated wilderness could not go forever unexploited. Though unsuited to supporting living communities, the hills proved far more accommodating for groups of undead. Such creatures didn’t mind getting lost, since they had no destinations anyway and had all the time in the world; they had no love for the sun, so the shade was a boon; and they had no need for farms and ranches to produce food. Over years, the number of undead in the hills grew to stunning proportions.
The more powerful undead forced their lesser brethren to built grand tombs, turned the peaceful corpses already interred within the hills into new kinds of undead, and seeped the powers of necromancy into the ground itself. A kind of hierarchy developed, and a black necropolis was built to serve as home to the throngs of undead. Unlike earlier societies of such creatures, the undead of the hills kept to themselves. It is unknown if this time of quiet was the calm before the storm, or if the walking corpses truly had no desire other than to be left alone by the living. In any case, they did not raid outside their borders or build any defenses that might be noticed by casual travelers.
Even so, it is surprising that this dangerous development went unnoticed by the guardian races of Faydwer. No report of vast armies of undead reached the lords of Felwithe, Kaladim, Kelethin, or far off Ak’Anon. Many have since suggested that some powerful being (probably a spellcaster) may have concealed the activities of the undead in the Hills of Shade — creatures ranging from Mayong Mistmoore to the dragon Trakanon and even the gods themselves have been suggested for this role. No real evidence of such a plot has ever been produced, but the suspicion remains that some force must have protected the black dead of the Hills of Shade.