Spoilers ahead for all Marvel movies through Black Panther.
Thanos (Josh Brolin) is supposed to be the biggest bad in the history of the Marvel Cinematic Universe. His goal is nothing less than reshaping reality, and yet so far he’s done more to illicit mockery than fear. While we got an enticing glance of the Mad Titan in the end credits of The Avengers, his appearances since then have been less than inspiring. In Guardians of the Galaxy, he seemed like a gigantic rube as he entrusted finding an Infinity Stone to Ronan (Lee Pace) only to have Ronan use the stone for himself, making Thanos come off as weak and easily conned. Then in Avengers: Age of Ultron we learned that the Mind Stone was inside of Loki’s scepter, which means that Thanos gave away one of the Infinity Stones he already had. At the end of Age of Ultron we get a, “Fine. I’ll do it myself,” but it doesn’t really mean anything other than showing that he has the Infinity Gauntlet. He also hasn’t showed up in any Marvel movie since, so we have no idea what he’s doing.
That’s a lot of pomp and circumstance that hasn’t amounted to much. Compare that to Black Panther’s Killmonger (Michael B. Jordan), and you can see why Thanos is in trouble from a narrative perspective. Killmonger is easily one of the best Marvel villains, and he leaves a mark despite never being introduced in a previous movie and dying at the end of Black Panther. Although Killmonger comes from the typical Marvel villain mold of being the unintentional side effect of a good person’s action (in this case T’Chaka, putting Wakandan isolationism above all, left a young Erik on the streets of Oakland with a dead father), his ideals are far more universal. He has a legitimate viewpoint that Wakanda owes it to black people all over the world to use their superior technology to overthrow governments and put their leadership on top. His methods—murder and warfare—are what’s controversial, but even that becomes a bit seductive through Jordan’s confident, brash performance.
Compare that to Thanos, who so far just seems like a dude who wants to destroy the fabric of reality by collecting Infinity Stones. It’s important for a villain to be relatable in some way, perhaps more so than the hero, so that we’re not completely divorced from his actions. It creates a conflict within the audience, so that even while we’re clearly against someone like Killmonger murdering innocent people, we can sympathize with his ideals and background. Thanos isn’t even human; in the comics, he’s the child of Eternals. While not being human isn’t prohibitive to being interesting (Loki isn’t human either), there are a lot of hurdles that Thanos has to clear.
Even if you set aside the fact that he’s a big purple alien, you still have to give him compelling motives, and that’s certainly possible. In the comics, Thanos is driven by the physical embodiment of Death. The story from Thanos’ perspective (again, in the comics), is a love story, and the tale of a guy who’s willing to do anything for the woman he loves. However, we’ve seen none of that over the course of eighteen movies. We’ve just seen a guy who wants Infinity Stones, and since his goals lack context, the goals themselves are currently uninteresting. If Thanos ends up being a dud, then his past appearances in Marvel movies will be diminished, and this culmination will seem like a misfire even though the MCU is now strong enough to whether any single flop.
I don’t want to jump the gun on Infinity War and tell the movie what it should and should not be about because directors Joe and Anthony Russo deserve to tell their story. But by the same token, since all Marvel movies are connected, that means they can’t help but be compared to each other, and Thanos is going to have to follow Killmonger. You have to follow one of the most charismatic and sympathetic villains the MCU has ever seen with…a purple man who wants magic stones.
This leads to what I fear might be a great irony about Avengers: Infinity War—that the Avengers will end up being supporting characters in their biggest movie to date. In order for the film as a whole to make an impact, and indeed for this culmination to make an impact, Thanos has to work as a character, which means he needs significant screen time. Black Panther is really two stories—one about T’Challa and one about Killmonger, and those stories inform each other and ultimately lead to T’Challa’s decision about the future of Wakanda. I’m not sure how you tell Thanos’ story in Infinity War, but hopefully it’s more than just a desire to destroy everything and collect colorful gems.