While the post-credits teaser of Thanos at the end of Age of Ultron did a decent enough job of reminding viewers that the real big bad of the series was still to come (albeit, not for another three years), the scene does throw a bit of a wrench in the works continuity-wise, raising the question of why the Mad Titan journeyed to Nidavellir to get his Infinity Gauntlet if he seemingly already possessed one. Granted, Avengers: Infinity War co-writer Christopher Markus has already offered his own quick interpretation of the chronology of the events, but this new Reddit theory suggests something slightly more elaborate.
User AhhBisto starts off with the claim that the gauntlet seen at the end of Age of Ultron turned out to be insufficient for harnessing the full power of the Infinity Stones, explaining:
“At the end of Age Of Ultron we see Thanos retrieve his Gauntlet and says he’ll do it himself but then he goes to Nidavellir to have a Gauntlet created by Eitri. People see this as a plot hole but it’s really not………they’re not the same fucking Gauntlet. When Thor, Rocket and Groot get to Nidavellir they notice a mould of the Gauntlet and Eitri explains that Thanos wanted “a device capable of harnessing the power of the Stones”.
So why go Eitri and the dwarves if he had one already? Because the one he had couldn’t hold the Stones and they could make him one, and the dwarves specialise in rare metals like Uru.”
The Redditor then goes on to argue that there’s precedent for this issue in the comic books.
“Here’s the thing about the Infinity Gauntlet itself, it started out as a piece of Thanos’ armour in the comics that Thanos re-designed to hold the power of the Infinity Stones, but over the years as the Stones have been used in stories more, their lore has expanded. One such story saw a villain called The Hood assemble 3 of the Stones by himself but without the Gauntlet, and doing so caused him physical harm each time he used them (this is in the 2010 Avengers series by Brian Bendis and John Romita Jr.) and he is warned by Doctor Strange (disguised as Thanos) that he will end up killing himself if he carried on because of the sheer power he was using.
So this was Thanos’ issue, he could physically hold one or two of the Stones without a Gauntlet to hold them as could most cosmic beings (and part of the reason why Peter Quill didn’t evaporate by touching the Power Stone in GOTG V1) but to literally wield INFINITY he would need something stronger. The only metals capable of “harnessing” the power of the Stones are the rare metals of the Marvel Universe, Uru would be one and i would bet Vibranium could possibly do it too.”
AhhBisto’s post goes on to cite a few more pieces of evidence to suggest that Thanos’ first gauntlet was inadequate without that Uru mold, and it’s clear that the user has put a fair amount of thought into this idea – too much perhaps, seeing how many fans have settled for the simpler explanation that the Age of Ultron post-credits teaser was taken from further down the timeline, slightly before the events of Avengers: Infinity War. But if this longer version of events seems more intriguing to you, by all means take it as truth until further notice.