Alright, I'm using this idea in my campaign (titled Innocence Lost) and in it there is a location quite distant from even the most remote parts of the fringes of civilization, tucked away in a nation forever frozen. Castle Iycewinde...
Alright, Let's get into the background. Castle Iycewinde was where a Princess once ruled, and her tyranny knew no end. Her nation was immensely powerful in the ways of magic, indeed her nation in its time was the leading superpower in terms of magic, artillery, and commerce. Magic in this world has since somewhat weakened, or at least many aspects and lore of it disappeared with Lossouls when it became eternally covered in a cozy blanket of ice a little over five centuries ago, with the beheading of the cruel princess. All records of this nation have been lost to time, what few remain are within the vaults of ancient liches and kingdoms long buried by sand. All that remains of this nation is a frozen and nightmarish wonderland, from which people bring back stories of shifting snow dunes and a land frozen seemingly in the midst of spring. Far, far to the north of its southern border on the sea, lies the heart of this forgotten nation, the still standing and foreboding Castle Iycewinde. There is a legend amid the Silver dragons that call this place home, and that is a description of this palace protected by the fiercest winds, blinding snows, and bitterly cold air, seemingly eminating from the castle itself. All who venture inside this monolithic structure never emerge from it again.
Alright, I need some help creating the horrors of the castle. I want to make it similar to Steven King's Rose Red, but I'm not sure how to go about doing so. And I want to keep it tied to the back story of the place. Can anyone give me some ideas as to what can be lurking behind its massive doors?
As a bit of a side note, the princess herself is still alive (albeit DM fiated eternal youth) and wishes to along with her recently resurrected twin brother (who took her place upon the guillotine in the first place) to restore their nation, as it was their fault that the nation's population dramatically fell, and then in its weakened state was eternally frozen. They'll be venturing to their castle with the party, in order to raid their own treasure vaults for a ring of wishes (known it is there by only them) and then they will be out of the picture forever.