Eitri is one of the secondary tritagonists of Avengers: Inifinity War. He was played by Peter Dinklage, who also portrayed Tyrion Lannister
Biography
Attacked by Rock Trolls
Eitri and his people were close allies of the Asgardians, to the point of even creating the mighty weapon Mjolnir after being asked by Odin to forge it.
When the Bifrost Bridge was destroyed, the Rock Trolls, having coveted the Dwarven Forges for many millenia, attacked Nidavellir knowing that Asgard could not come to defend King Eitri and his people. Using the power of the Tesseract, Heimdall was able to rebuild the bridge and aid Nidavellir; as a result, the Rock Trolls were defeated by Thor and the Asgardian army.
Infinity War
During Thanos' reign of terror on the universe, Thor travels to Nidavellir with Rocket Racoon and Groot, intending to forge a weapon that can kill Thanos, only to find Eitri the last surviving creature in the area, a giant, metallic ring surrounding a dying star. Eitri accuses Thor and Asgard of not protecting the dwarves during the attack of the Rock Trolls, until Thor reveals that Asgard has been destroyed. Eitri reveals that Thanos forced him to create the Infinity Gauntlet, a device capable of harnessing the powers of all the Infinity Stones, by threatening all his fellow dwarfs. When the gauntlet was completed, Thanos reneged and killed all the dwarfs except Eitri, as well as mutilating his hands in an attempt to prevent him from forging anything else, and absconded with the gauntlet. Thor nonetheless convinces him to build the weapon.
Eitri decides to forge a battle-axe known as Stormbreaker that, as well as having the powers of Mjolnir (except its worthiness enchantment), can also summon the Bifrost. The ring serves as a mechanism that can harness the energy of a dying star to melt a cosmic metal known as Uru, allowing Eitri to make his weapons.
With Thor and Rocket's help, the ring is locked into place to begin harnessing the energy, but the mechanism is crippled, forcing Thor to hold it open and let the energy flow through him, critically injuring himself, in order to allow Eitri to heat the metal. Eitri continues forging the axe, knowing it will save Thor's life, but realizes the handle is missing. Groot uses his tree-extensions as a new handle, thus finishing the axe and allowing Thor to summon it to himself.
Although the axe allows Thor to join his fellow Avengers in Wakanda, the battle, and the entire Infinity War, results in Thanos using the Infinity Stones to disintegrating half of all life in the universe, only for the Hulk to reverse the disintegrations five years later; it is unknown whether Eitri was among the victims.
