Great Linnorm of Frostheart

Linnorms are terrifying giant snakes relative to the Dragons that have haunted the cold lands of Skutagaard for centuries. It is said that the scales of a Linnorm are resistant like Vorgul, the dark metal used by the Dwarves of the depths; thanks to them they can camouflage themselves or emit powerful flashes of light. These enormous creatures are gifted of great intellect and are capable of speech.
Ravenous predators of any living thing that crosses their territory, Linnorms love to accumulate treasures and magic trinkets, a strategy that easily attract greedy adventurers and trolls.
The bite of a linnorm possesses the mysterious ability to suck the life out of a living being, turning it into an empty husk.
According to the natives of Skutagaard, Linnorms were once benevolent spirits who guided the valiant warriors fallen in battle into the Mead Hall, but when King Skutagaard turned into the Lich Lord, his necromantic magic began to corrupt the souls of the fallen. Linnorms who met these poor souls went mad in turn, converting themselves into the hideous monsters we know today.
According to the opinion of few survivors, a Linnorm grows the more it feeds, the Skald ballads sing about Linnorms so huge to destroyed entire cities.

But no Linnorm is fierce and massive as the Great Linnorm, the scourge of the dwarven kingdom of Goldvein, on the Frostheart Island; homeland of the fallen hero Thane Ulgrof himself.
Kings among the monsters, the Great Linnorm decimated the population of Frostheart, converting it into a cursed island.
The stories tell that it was precisely the Frostheart Gem, found by the dwarves in the depths of the heart of the island, that attracted such a disaster on their people.
During the last hundred years, various expeditions tried to seal to this cursed island of Skutagaard to recover the precious Frostheart Gem, but subduing - or defeating - the greedy Great Linnorm in his lair in the ancient kingdom of Golgvdein beneath the mountain is a feat no one has yet managed to accomplish.