Will the mask smile for you or frown? Do you know who you are? Do you really?
“In the Black, dead souls creep
Seeking vengence without sleep.
Sacrificed for precious stones,
Rend they now flesh and bones.
Bloody staind and drenched in tears,
Stones cry out to one who hears,
‘Treachery has sown the seeds!
Now you’ll be the one who bleeds!
Wear us well, you who brave,
Next you’ll be in the grave!’”
- Tas-Vessina’s curse
A strange, mystical box, with many rumours attached, that does not want to reveal its secret…
“First, I nibbled on his earlobe. Then, I bit into it, letting the red, red blood roll down his neck. Then, when he screamed and started tearing at me, I ripped the flesh from his hand. Ah, it tasted so good! Yes, yes! Then, I ripped through his jugular, and bit through his spine! Yessss…..”
I am the mask that grins and lies
I'll hide your face and shield your eyes....
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...