Uru is a metal forged in the furnaces of Nidavellir. It is purportedly so powerful that the only way to melt it down for forging is with the power and heat of a dying star.
Creation of Mjølnir
Forging the Infinity Gauntlet
In order to harness the power of the Infinity Stones, Thanos traveled to Nidavellir to commission the device. When the Dwarf king Eitri refused, Thanos threatened his subjects, with the Dwarf relenting, crafting a Gauntlet using an uru mold. With the gauntlet completed, Thanos killed all 299 of Eitri's subjects. To further prevent anyone else from receiving such powerful equipment of Eitri's design, he then proceeded to encase the Dwarf's hands in molten metal, leaving him to become crippled and to suffer all alone.
Thor, Rocket Raccoon, and Groot traveled to Nidavellir to claim a new weapon in order to kill Thanos before he could complete the Infinity Gauntlet. Upon arrival, the trio discovered a somber Eitri, who agreed to help the trio kill Thanos for taking his hands and killing his people. Selecting the most powerful Uru mold, the group created the Stormbreaker, with Groot using his own arm as the handle for the weapon, as Eitri misplaced the original.
- In the non-canon game Thor: The Dark World - The Official Game, The Dwarves used Uru to create several powerful weapons including Mjølnir, the Bloodaxe and the Sword of Torunn. The Dark Elves attacked Nidavellir, stealing the Bloodaxe and the Sword of Torunn. Thor and his allies tracked them down and recovered them.