You've just come from seeing The Avengers. Your audience was rapturous throughout, and at the end everybody applauded. The credits rolled, ran a bit and then... space! The Chitauri leader is standing on a floating rock in space, talking to some guy. The guy turns around, smiles at the camera and... that's it. The whole audience (except for many two or three hardcore nerds) goes 'What the fuck?'
I must admit that the way The Avengers ends, with this mystery guy just looking into the camera, is ballsy. Most viewers will have absolutely no idea who this guy is. He doesn't say anything or do anything that really gives you much of a clue. And yet it seems like he's pretty important.
He is, and the good news is that I am such a huge Marvel Zombie I can tell you all about this dude. With this explanatory (and spoiler buffering) text out of the way, let me tell you about:
Thanos, The Mad Titan!
Already you can tell this is going to get nerdy. I'll start simple and get more complex.
Thanos is a member of the Eternals, a godlike race, some of whom live on Saturn's moon Titan. The rest of the Eternals are pretty (Thanos' brother is Eros, which should tell you something about what he's like. Eros is sometimes an Avenger under the name Starfox), but Thanos looks like a statue took a shit into a blue jumpsuit. In addition to being ugly, he's also an immense asshole and on top of that he's hung up on a girl. It's not just any girl. He's in love with Death. And I don't mean that in some vague, "He likes killing" way. I mean he is in love with the anthropomorphic personification of Death, which in the Marvel Universe is a woman. At one point he obtains absolute omnipotence and uses it to wipe out half the life in the universe as an offering to Death.
That's why his appearance in the movie is even nerdier. He turns and smiles when the Chitauri leader says "To attack Earth would be to court death." Because Thanos would like to LITERALLY COURT DEATH, as in take her out for a drink and a movie and back to his place to look at his etchings (in his face).
Some more on Thanos: The first thing he did of note is to wipe out millions of his own people on Titan. Then he came to Earth looking to get the Cosmic Cube (which you know from the Marvel Movieverse as The Tesseract), hoping to use its power to impress Death. He was stopped by Captain Mar-vell, an alien soldier (who later died of cancer).
Thanos gets defeated when Mar-vell destroys the Cosmic Cube (don't worry, they make more). Later, Thanos teams up with a Space Christ named Adam Warlock (a guy whose history is so weird and complicated that we'll leave it at the fact that he's all gold and hangs out with a cigar-smoking midget troll) to defeat the Magus, who is an evil AFRO'ED version of Adam Warlock*. While they're fighting, sneaky Thanos siphons the power of Adam Warlock's Soul Gem. Warlock wears the Soul Gem on his forehead, and it gives him the power to steal or control souls, as well as opens the door to a pocket dimension (I told you it would get more complex). Thanos uses the Soul Gem's power to build a weapon that can blow up stars.
This story is pretty big. It takes all of The Avengers, Spider-Man and The Thing, as well as ole Captain Mar-vell to stop Thanos. He turns into a statue, which seems like not much of a difference, really.
But Thanos isn't done yet! He has his biggest plans yet to come.
Years later Death herself resurrects Thanos. She's upset because there are now more beings alive in the universe than there are dead, and she wants the imbalance fixed. She wants half the universe killed. Thanos decides the only way to do this is to collect the Inifinity Gems - of which the Soul Gem was but one. There are six Infinity Gems in total, and Thanos travels the cosmos collecting them. He forges them into a gauntlet that he wears - aka the Infinity Gauntlet. I'm not sure how this already showed up in the Marvel movies, but it did.
With the Infinity Gauntlet Thanos is omnipotent and omniscient. Thanos is now God. In a blink of an eye he wipes out half the living beings in the universe. When the superheroes of Earth (the ones who didn't die in the initial wipe. The immediate dead include Daredevil, the Fantastic Four and most of the X-Men) hear about this, they assemble to battle Thanos on the space rock where he's hanging out.
Thanos kills every single superhero. He plays with them a little bit, giving them a chance to actually hit him, but in the end he kills every single one. He encases Cyclops' head in an unbreakable, airtight box. He turns Thor to glass and shatters him. He turns Wolverine's bones to jelly. Iron Man is decapitated. Spider-Man has his head crished. The last Earth hero to stand before Thanos is Captain America, who is defiant in the face of imminent death. With a smack Thanos shatter's Cap's unbreakable shield and breaks the super soldier's neck with a pimp slap.
That's Infinity Gauntlet #4, and I think it's the best single issue of one of these types of crossover stories. A huge part of that comes from the mix of writer Jim Starlin and artists George Perez and Ron Lim. The storytelling is incredible - just scanning through the pages the fight is intense and incredible.
Anyway, he kills all the superheroes AND he's God. And there are still two issues left of the miniseries. How do the good guys win? Read the comic! It's linked below. I highly recommend it. I will say that, in the best Marvel tradition, Thanos' biggest weakness is his own self-doubt.
Thanos ends up roundly defeated once again. The Infinity Gauntlet is the pinnacle of Thanos' story, and it's been done in a couple of different formats in the years since. Thanos pops up still, but he's never quite matched up to his antics in The Infinity Gauntlet, and I doubt he will.
At least not until The Avengers 2.