The legend of the accursed Jewel of Jerrimore can trace its origins to the third century Before Entharion in the northlands of Frobozz. This jewel, which is a stunningly beautiful star sapphire, is said to have been cursed by the Mage of Jerrimore as he lay upon his deathbed. As he sickened, this powerful but twisted wizard became convinced that his enemies had poisoned him to gain possession of his greatest treasure, the Jewel of Jerrimore. With his dying breath, he loosed a great and evil curse upon the Jewel and all who would possess it. After the Mage's death, each of his heirs took possesion of the jewel; each held it jealously, mistrusting any who might look upon it; each became obsessed with the greed and treachery they perceived around them; and each came to early and horrible deaths. Thus grew the legend of the cursed Jewel.

Although the legends vary, all versions say that the Jewel travelled through many lands, always leaving a wake of misery and death, was somehow brought across the Great Sea long before the invasion of Duncanthrax, and became lost for many years in an iron mine near the Flathead Fjord (Fjord Site B) which was sealed. The entrance to the iron mine is still today marked by strange and frigthening runes proclaiming a warning of inevitable death to anyone who took the Jewel, although it was since removed in 883 GUE by the daring adventurer who would become the First Dungeon Master, who used it as part of a complex plot that would eventually result in the fall of the Great Underground Empire. In the year 949, the jewel was located at the Steppinthrax Monastery museum; but it, along with many of the relics located within were afterwards dispersed (most likely stolen). The final fate of the Jewel is not known.

When the reflection of the Jewel of Jerrimore was studied in Mirror Lake, the bony skeletal hand of Death was seen clamped around it, laughing silently from within his dark cowl.