Wyrmfallen

Wyrmfallen is a disease of madness that wiped out the dwarvish nations of the Iron Teeth Mountains. Amongst dwarves it is referred to as a curse, the dragon's rapture. It comes from a form of false Mythrall also known as wyrmfallen.    Continued exposure to the metal creates rising mental instability and obsession, particularly with reflective surfaces. This obsession draws the ill to mirrors, gold, silver, platinum, mythrall, polished metal works, jewelry, even the surface of waters. Hoarding and collecting become vital and the obsession draws the victim into seclusion with whatever they believe they see in those reflections. Cure Disease and Greater Restoration do not cure it. It is said that the dwarven smiths, kings, and queens fell ill to this before their alchemists and smiths determined that the metal must be processed further.    Greater magics might reverse the illness, but the dwarvish kingdoms were lost to it.  Those not driven to their deaths remained in the Iron teeth, a massive mausoleum to the dead. Some even embraced the madness and went deeper becoming the duergar of the underdark.