“ 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...”
“ A military organization, the Stalkers are a hunting/mining militia that are known for wearing full body shrouds that easily hide them in snow and other slushy terrain. The lightly armored warriors are known for the speed, stealth, and the vicious wounds inflicted by their hunting hatchets. Many of the Stalkers keep crop-eared warhounds with them, both for hunting, companionship, and in war.”
“ When creating nations or cultures that reside in your desert regions, consider pulling inspiration from the Berbers or Bedouins, rather than the easily-mishandled Iranian/Persian/Arab convention”