The Sandstorm and the Undead Curse

Nearly all magic can be traced back to the Great Fairy. However, the sandstorm that roils at the edge of the valley, which traps the valley's inhabitants in a thousand-mile wall of impenetrable desert, was ordained by forces outside even the Great Fairy's comprehension. The beginning of the eternal sandstorm also coincided with another metaphysical phenomenon: the rise of the undead. The reanimation of the dead's skeletal remains, commonly called the Undead Curse, seems to share a strange connection with the sandstorm. This connection can be illustrated when one engages in the necromantic arts.

Manifestation

The sandstorm encircles the valley, just beyond the mountains. It extends tens of thousands of feet into the sky and seems endless. Even the avians, blessed with the power of flight, find themselves incapable of rising above the storm before running out of stamina, oxygen, or both. Boring beneath the surface is futile, as the underground is the domain of dragons, so the valley's inhabitants are effectively trapped. It does appear possible to instantly transpose matter inside and outside the valley via the Elvish magics, so in theory it may be possible to teleport to and from the valley to supersede the sandstorm. However, all those who have attempted such a feat have never returned. It is unclear if they succeeded and did not wish to return or if they died trying.
Death in the valley means very little. When deceased remains come into contact with any form of magic, the deceased individual is brought back to life. The caveat is that only their skeletons remain, although they can still walk, talk, and act as though they have all the necessary muscles. The undead are immortal and unkillable, rendering a true death in the valley impossible.
The undead have a strange and inexplicable connection to the sandstorm. They are all drawn into it at one point or another, like moths to a flame; it is seen as a great honor in undead society to take the pilgrimage into the sandstorm with the hopes of seeing the other side. In truth, all undead succumb to madness amidst the dunes.
There is also the strange matter of necromancers, who seek to undo the Undead Curse and restore the entire bodily form of the deceased. As the activity of necromancers has steadily increased over the years, so too has the encroachment of the sandstorm inland steadily increased. Almudic researchers first noticed a correlation when hundreds of "curse-broken" elves imprisoned at Baran-gal suddenly reverted to their undead forms, consequently rolling the sandstorm back across the valley. Two schools of thought emerge from this research:
1. The sandstorm and the Undead Curse were brought on simultaneously by the same entity and are intrinsically linked.
2. The two phenomena were brought on by two entities: one wishing to smite all life in the valley with a sandstorm and one that successfully shielded all life in the valley from harm with the Undead Curse.
In either case, the truth is clear: should the Undead Curse ever be reverted entirely, all life would succumb to death and madness in the storm.

Type

Metaphysical, Divine