The sword which Óðr recovers from the boulder placed over his mother’s grave has an interesting history.

It means literally Vör’s “walking-stick” or “divining rod”, from the Old High German pfal  (staff), borrowed from Latin pālus (stake), possibly through a late Proto-Germanic intermediate. Compare Old Dutch pāl (Dutch paal) and Old English pāl (English pole). 

Vör is one of the elder Jötnar who survived the deluge that drowned most of Ymir’s kin. Daughter of Bölþorn, sister to Mimir and Bestla, and aunt of Óðinn, Vili and Vé Snorri mentions her in chapter 35 of Gylfaginning as part of his catalogue of Ásynjur:

The tenth is Vör: she is wise and inquiring, so that nothing can be concealed from her. It is a saying, that a woman becomes aware (vor) of something when she finds it out.

Although she presents as a blind, decrepit crone (at least according to her modern devotees) Vör is actually a powerful seeress and her walking stick was originally a branch from Yggdrasil gifted her by Óðinn. Whenever she touched it to the Earth she could discern the flow of water, no matter how deep underground it might be. After the deluge receded Ásgarðr was left waterless and in danger of becoming a barren desert. Óðinn knew that she would not help for Vör was still wroth with him over the murder of Ymir, so he enlisted the aid of her brother Mimir who could foresee the deaths of all, himself included. He pleaded with Vör to help the Æsir to recover their rivers, lakes and streams from the greedy Earth or he would lose his head, and she grudgingly accepted.

Later she came to visit the Gods in Vanaheimr. Though impressed with her skill as a spákona, Gullveig offered to teach her the art of seiðr – in exchange for her walking stick. Vör considered it a bargain at half the price, especially since she knew that it bore a terrible curse. Coming as it did from Yggdrasil the stick perpetually thirsted for blood. Once the exchange had been made Gullveig gave the stick to her King and Njörðr brought it to the Sons of Ivaldi so that they might craft it into a deadly weapon. They encased it in metal that glowed like the hair of Sunna no matter how dark one’s surroundings and Njörðr was victorious whenever he carried it into battle. However it was no longer satisfied just with drinking blood; it refused to be sheathed until it had been used to decapitate the wielder’s foes.

And so it was that Njörðr left it plunged into the boulder after his encounter with the giant she-bear. Although ignorant at first of the curse the blade bore, Óðr was less bothered by this than his adopted father, and campaigned far and wide with it, subduing many of the neighboring realms and collecting innumerable heads in the process. He did not, however, wield it during the Æsir-Vanir War for it had already been lost by then.

A cousin of Frænir was once harassing the borderlands of Vanaheimr and so Óðr, Freyr and Wanlan rode out to slay the loathsome beast, whose name meant “voluble fruit.” During the course of the battle Wanlan was mortally wounded; as Óðr was looking after him the dragon used that momentary distraction to steal the sword and fly off with it, for like all its kind it was attracted by shiny things and scarce was there anything in the Nine Worlds shinier than this sword.

Although Óðr searched far and wide, he was never able to find the dragon or its lair, and so had to settle for using his other weapons.

Even Vör, who joined the Retinue of Frigga after the Æsir-Vanir War, could not locate it.