Few things shine as bright as the jewels of Hell
A rare and diseased jewel, a canker fallen from the heavens
“Gold. GOLD. GOLD! Beautiful, wonderous, Gold! I am Rich I tell you. I am the luckiest man alive!”
“Ever in my hand, lies the Blade of the Mad. It’s straight, simple craft is so alluring to me… It drives me to evil, but I love what it does. For the first blood the blade tasted was that of a human.”
A plague has hit the local area.
In humans it affects only the most vulnerable, the children and the very old, and even than it's little more than a summer cold. 24 hours of sniffles and then it's gone, barely noticeable really.
To sheep however it is fatal and the whole economy of the area is in serious trouble. If this keeps up the area could well be facing famine.
Somebody (enter the PCs) must find the rare herbs needed to make a cure.