The Infinity Gauntlet used by the villain Thanos to channel the Infinity Stones in Marvel Studios' Avengers: Infinity War was forged by the Dwarven blacksmith Eitri on Nidavellir, and was implicitly finished just before the events of the 2018 film. This seemed to create a continuity problem for the Marvel Cinematic Universe, as the Infinity Gauntlet had already been seen in previous films. However, Infinity War writers Christopher Markus and Stephen McFeely have an explanation for why exactly the "fake" gauntlets exist.The first glimpse of the Infinity Gauntlet was caught all the way back in 2011's Thor, with the relic residing in Odin's vault on Asgard. At the time, it seemed like little more than an easter egg for savvy comic book fans. When the MCU began building towards Infinity War in earnest, however, it raised more questions. Odin's gauntlet resurfaced in 2017's Thor: Ragnarok -- the second-to-last Marvel film before Infinity War -- with Hela sneering that it was "fake" and knocking it over. Still, fans have questioned why a fake exists at all. Furthermore, Thanos was seen putting on another Infinity Gauntlet during the post-credits scene of 2015's Avengers: Age of Ultron, declaring, "Fine, I'll do it myself."The Age of Ultron sequence specifically was brought up during Markus and McFeely's Infinity War two-year anniversary watch party on ComicBook.com's Twitter, with a fan asking if that sequence had any connection to Eitri. One (or both) of the writers replied, "I believe there is an existing myth of a gauntlet that could unify the stones. Hence, the fake one in Odin's vault, and Thanos wearing this fashionable 'practice gauntlet.' When he needed a real one, he went to Eitri. Who also provided a handy carrying case." (Attached to the tweet is a photo of the Infinity Gauntlet prop inside is case.)
In the Marvel Comics limited series The Infinity Gauntlet by Jim Starlin, George Pérez and Ron Lim, Thanos uses the eponymous device to snap his fingers and kill half of all living beings in the universe, which he does in an effort to win the favor of Death. Thanos' goal remains the same in Marvel Studios' Infinity War, though his motivation has changed, with the snap instead being an extreme method of population control to prevent the overuse of the universe's resources. The Mad Titan is ultimately successful in his mission, setting the stage for the Infinity Saga's climax in 2019's Avengers: Endgame.