Said to be the mighiest of all weapons, Grueslayer was the legendary blade of Entharion the Wise. With this sword he single-handedly slew many ravenous grues (for many years the entire devilish race was thought to have been eradicated at his hands). The Sheath, as probably with the Blade as well, retained magical powers of much virtue: he who wears it is blessed with wondrous powers of recuperation. The Sheath refuses to permit any sword to enter it but Grueslayer itself.

Although the blade was lost, a six-inch fragment of steel which was its broken end was found in the possession of the Nezgeth tribe in 398 GUE, which used it as part of their rituals to their so-called gods. Both the reforged blade and its sheath were part of the Steppinthrax Monastery's museum display in 949; but they, along with many of the relics within, were dispersed shortly thereafter (most likely stolen) and journeyed elsewhere. The Sheath of Grueslayer survived at least until 966, when it was purchased by an unknown peasant for the mere price of Zm80 from the Accardi weapons shop run by Y'Gael. Hazy accounts tell that eventually the Blade and Sheath were reunited. If Grueslayer were to resurface today, it would definitely worth at least half the wealth of the kingdom of Quendor.