Over at the official website for Marvel Studios' Avengers, each character has a bio as part of the site's slick new design. There's isn't any new information there except for when you read Loki's bio. This isn't a huge revelation by any stretch of the imagination but I believe it does merit some attention.
BIO: "After his bid to overthrow the throne of Asgard was thwarted by his brother Thor (Chris Hemsworth), the evil Loki (Tom Hiddleston) retreated to lands unknown to plot his revenge. Not just against his brother, but against Earth, whose inhabitants Thor now protects. Loki, now returns with a nefarious plot to conquer Earth and will stop at nothing to see his vision realized. When his misuse of power threatens the entire planet, it may take more than The Avengers to stop him."
What could this cryptic line possibly be referring to? My initial thought was that they're teasing that Odin would be a factor in finally putting Loki down but then I remembered that Tom Hiddleston has previously stated that Odin will not be appearing in the movie. My next thought was that some other character would be turning up to assist the team but then I remembered that Kevin Feige has stated that no new heroes will be introduced in the film. Finally, I remembered that Tom Hiddleston has been stating in numerous interviews that Loki is a very "complex character and a shape-shifter" and it's possible that Loki could change sides to become good. Based on that info from Hiddleston [you should really go back and read that interview] I think it's possible that we may get a reversal of Loki's development in Thor. When we first met Loki he fought alongside Thor and The Warriors 3 and was only a tad bit mischievous and scheming. It wasn't until he discovered the truth about his parentage that he went all-out villain. Taking Hiddleston's quote at face value, it seems that we may get a reversal of that development in The Avengers and Loki could start out as a villain but waver and ultimately falter by the end of the movie. Perhaps, elder brother Thor is able to appeal to what little goodness remains within Loki? It would certainly be in keeping with his comic book counterpart and would account for that "it may take more than The Avengers to stop him" bit at the end of Loki's bio.
Still, this is only speculation on my part. That line could very easily refer to The Avengers acquiring a device from Odin's vault or maybe someone from one of the worlds Loki visited in-between Thor and Avengers [Feige stated no heroes will cameo, he said nothing about villains] will be that extra-something that tilts the victory scale in The Avengers favor at the end of the day.
The Avengers is an upcoming American superhero film produced by Marvel Studios and distributed by Walt Disney Studios Motion Pictures1, based on the Marvel Comics superhero team of the same name. It is part of the Marvel Cinematic Universe, which crosses over several Marvel superhero films including Iron Man (2008), The Incredible Hulk (2008), Iron Man 2 (2010), Thor (2011) and Captain America: The First Avenger (2011). The film is written and directed by Joss Whedon and features an ensemble cast, which includes Robert Downey, Jr., Chris Evans, Mark Ruffalo, Chris Hemsworth, Scarlett Johansson, Jeremy Renner and Samuel L. Jackson. In The Avengers, Nick Fury, director of the peacekeeping organization S.H.I.E.L.D., recruits Iron Man, Hulk, Thor, and Captain America to save the world from destruction.
Development of The Avengers began when Marvel Studios received a grant from Merrill Lynch in April 2005. After the success of the film Iron Man, Marvel announced that The Avengers would be released in July 2011. With the signing of Scarlett Johansson in March 2009, the film was pushed back for a 2012 release. Whedon was brought on board in April 2010 and rewrote the screenplay that was originally written by Zak Penn. Production began in April 2011 in Albuquerque, New Mexico, before moving to Cleveland, Ohio, in August and New York City in September.
The Avengers is scheduled for release on May 4, 2012 in the United States.