Plague / Epidemic
The Shadowed Death sweeps through the Hollow Mountains, killing thousands. The shadow elf population is decimated and with the disease's impact on their fertility, any recovery in population numbers seems unlikely.
Part disease and part curse, the Shadowed Death destroys the binding between the soul and the body. The healers of Taureluum attempt to slow the spread of the disease by heling victims with magic, however they miss an important aspect of the disease. Though they cured physical symptoms, the curse remained, eating away at the binding of the soul. Eventually the victims became empty husks, with no possibility of the soul returning to the body. Resurrection of these people proved impossible. Once they realized that the disease was part curse, containment of the disease became possible. A true cure was never found, however. The disease's progression could only be paused, and it was incredibly dangerous to contract the disease a second time, as its progression continued on from where it left off. The shadow elves seemed to be particularly susceptible and, for unknown reasons, it had a negative affect on their fertility. Full-blooded shadow elf births became increasing rare, leading to a shift in population towards half-elves.