“ With a huge number of sacrificial victims, another realm long ago secretly bound a Prince of the land spirits, Iorstonn by name, thus ensuring the fertility, and improving the magical defences, of their realm. But binding that Prince to one spot has disrupted the weather and magical patterns (ley lines?) over half the continent. Things have become bad enough that a coalition has been formed to rectify the situation, once divinations have established the cause.
Your party is one of the teams assembled to do the rectification: find the binding object and steal it ('so that we can destroy it here in our realm, of course'...*) or destroy it over there. Presumably the Prince will be grateful to his rescuers and angry at the binders, but with a greater spirit like Iorstonn one can never be sure: such beings are 'tricksy'.
* Of course, the rulers of our realm might want to control Iorstonn for their own ends...”
“ Suppoki-
These creatures are desert animals that are much like huge, quadripedal sloths. They have a hide made of heavy scales to keep out gritting sand, and over that, a thick coat of fur.
During sandstorms, and when they sleep, Suppoki bed down in the sand, covering themselves up until they are miniature dunes.
Suppoki derive what sustenance they can from water sinks, dew, and underground insects.
Suppoki are often ridden by desert tribesmen. They are stubborn and slow, but are often the difference between life and death out on the sands.”
“ An alloy of iron and iridescent meteoric metal, also known as shadesteel. Weapons forged of this metal cause gangreneous infections almost instantly and sometimes the victims becomes a shambling zombie after death. The material is very vulnerable to fresh water which will cause it to corrode and eventually melt in a period of hours to days.”