WARNING: This article contains massive spoilers for Avengers: Infinity War, in theaters now.
The Marvel Cinematic Universe has always been pretty loose when it comes to adapting the comics, and Avengers: Infinity War is no different. As expected, in repurposing the famous Infinity Gauntlet series, the studio took liberties in reshaping key players, including Josh Brolin's Thanos.
In illustrating the Mad Titan's journey, the Russo brothers, while wandering off the path that we're accustomed to, actually left some breadcrumbs behind, hinting that his retcon might be something more than we first assumed. Rather than Thanos being just an overpowered villain, the clues indicate he may well be an Elder of the Universe.
In the comics, the Elders were introduced in 1978's Avengers #174 as a unique collective of cosmic beings. They're the last survivors of otherwise extinct races, known for their personal obsessions which include collecting artifacts (such as the Infinity Gems), gaming (which as seen in Avengers: No Surrender involved the kidnapping of Earth and childishly placing its heroes against resurrected villains), and fighting (which often happens amongst each other and ends up affecting the galaxy adversely). Simply put, to them, the fate of the universe is secondary to their personal obsessions.
While some of these characters have been introduced to the MCU, they haven't been officially labelled as Elders. The Collector (Benicio del Toro) debuted in Thor: The Dark World as someone collecting rare items of power like the Infinity Stones, while the Grandmaster (Jeff Goldblum) appeared in Thor: Ragnarok as the ruler of Sakaar, enjoying a life of gladiator fights and constant partying. As for another 'Elder,' Ego The Living Planet was introduced in Guardians of the Galaxy Vol. 2 as a Celestial who wanted to take over the galaxy.
These characters bear the same traits as their comic counterparts: they all have frivolous hobbies, ulterior motives for their actions, and most of all, they're eons old. This lines up with Thanos in Infinity War: someone who loves treasure-hunting as a pastime, someone who's sole purpose is to balance the galaxy, and, from his speeches about the regression of the universe, someone who's very old and a bedrock of the universe.
We can also tell that he's filled with knowledge, displayed with his detailing of the demise of his home-world, Titan, after it ignored his lethal strategy for population control, and his subsequent obsession for "curing" the universe. It's clear he's the villain but still, he's so very wise. This is the kind of knowledge you accumulate from experience, and as he details his crusades of bloodshed, you get a fair idea of how much he's seen when it comes to the galaxy evolving, or according to him, devolving over the ages.
Given that he also calls the Collector by his real name -- Taneleer Tivan -- when he's hunting the Reality Stone, it's safe to say they have a prior relationship, which the eccentric hoarder would likely only have with buyers, sellers or someone within his inner-circle, which we know to be pretty small. Thus, it isn't far-fetched to picture both were once a part of an ancient group of seekers -- of knowledge and artifacts -- looking to unravel the secrets of the universe.
His education as an elderly cosmic entity may well be what enables Thanos to handle the Infinity Stones, too -- something the Elders did in the comics. Sure, he needs a Gauntlet to fully harness their combined power, but throughout Infinity War, he's holding the Stones with his bare hands, even crushing the Tesseract like an egg to extract the Space Stone. As the Collector said, only powerful beings can wield them so nonchalantly, and while Ronan, Malekith and Star-Lord (Ego's half-human son) did once wield a Stone, they held a single gem, not multiple ones. Plus, it nearly killed them when they did, while Thanos appears to suffer no ill effects aside from a moment of possible discomfort.
Ultimately, Thanos' attitude and the way he looks down on everything and everyone does hint that he's an Elder that's been around the block. This would make a lot of sense, because he already existed as a godlike figure even before he filled his Gauntlet. Treating the galaxy like a broken toy and 'fixing' it the way Thanos did is something an Elder would do, especially while smiling in the face of the destruction being caused.
Directed by Joe and Anthony Russo, Avengers: Infinity War stars Robert Downey Jr., Chris Evans, Chris Hemsworth, Mark Ruffalo, Jeremy Renner, Scarlett Johansson, Anthony Mackie, Paul Rudd, Elizabeth Olsen, Tom Holland, Benedict Cumberbatch, Chadwick Boseman, Chris Pratt, Zoe Saldana, Dave Bautista, Bradley Cooper, Vin Diesel, Tom Hiddleston, and Josh Brolin. The film is in theaters now.