The following is written for use in whatever game system, or edition there of, you prefer.
THE COLD BRIDE
Also Known As: Burial Maiden, Mound Maiden, Ice Wife
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Arteman walked to the stone sarcophagus carefully, watching for the slightest signs of a trap or trigger spell. The Jarls of old were known to jealously protect their burial hoards with both physical and magical wards.
Jorda Singh chuckled. "You approach the dead as timidly as a virgin, their master." The dark skinned Turanian's bearded face split wide with a feral smile.
The younger elf just smiled and shook his head. "You wish I approached you as cautiously, my Lion." His face grew serious. "These northern chieftains were as jealous as dragons with their gold. Even hundreds of years after their deaths, they can be just as deadly too."
"Old wives'tales and superstitions," spat Voramir. The tiefling warlock sneered, "These filthy barbarians, and their weakling gods, pose no threat to a true son of the Nether Realms.
Both the human fighter and elf thief just glared at the arrogant half-blood and shook their heads. They knew better than to dismiss the northern born so out of hand. They might be savages, but there was nothing weak about these people.
The young elf inspected the stone encasement carefully, making note of the occasional hole drilled here and there, and of the futhark runes carved along the top. His understanding of the language was limited, but it seemed to pertain to both a burial and a marriage contract. He just shook his head, not making any sense of the context of what he was seeing. Careful investigation of the holes showed no signs of traps. After a nod of his head, Jorda slipped up beside him, and together they prepared to slide the heavy stone lid aside.
Almost instantly, a light bluish fog began to pour out of the holes, swirling and coalescing into the ghostly face and torso of a northern woman. He eyes blazed as she cupped Arteman's face and drew him irresistibly to her lips and kissed him. Jorda, watched in horror as his lover began to turn blue and frosted with ice.
"You witch! I shall send you to the Hell of Burning Sands!" The human drew his heavy tulwar from its scabbard as quick as thought, and slashed the blade harmlessly through the ghostly image.
The tiefling warlock stepped back in surprise, but rallied himself. "Spirit of death and ice, you shall not survive the setting of the sun this day!" His hands began an intricate arcane dance as ancient words of power spilled from his lips...
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The ancient North Men were a people of traditions and magics long before the coming of the foreigners. Their's is the legacy of legendary heroic battles and great treasures won from the clutches of ferocious beasts and malignant spellcasters.
The treasures of old were often jealously guarded by protective spells, curses, and terrifying monsters.This article is about one such guardian, the Cold Bride. Some men are consumed with greed and jealousy in life, and so some are in death as well. The Cold Bride is the result of a terrible curse, a ritual marriage performed upon the burial of a powerful chieftain. A young woman is taken, her throat slit, and her body buried with the corpse of her "husband". Her restless spirit is then condemned for eternity to guard his burial site and treasures.
Most games have mechanics for the undead, specifically vampires. The Cold Bride is a variation of vampire in my home campaign, with only a few differences. She may change herself into the form of mist, a small woodland creature, or a bird no larger than a raven. She is not effected by a crucifix, or sunlight, but does stay back from open flames and can be destroyed by fire. Depending on the campaign and rules system used, there can be lesser and greater versions of the Cold Bride, with the greater versions being able to turn hapless victims into lesser undead guardians.
Cold Brides do not roam the countryside and feed like regular vampires, they do not need to feed at all to remain strong. They will remain close to the burial site, only venturing out, even in full daylight, to scout for approaching intruders. As Game Master, you can have them do as you like, but in my campaign they usually don't do anything outside of the burial site to draw attention, giving no warning or sign that anything is amiss.