According to Variety and Latino Review, Josh Brolin has officially been cast as the cosmic villain Thanos in the upcoming Guardians of the Galaxy. Fans can also expect Brolin to reprise the role in Avengers: Age of Ultron, due out next year.
What role will this galactic despot play?
Thanos is a popular villain among Marvel fans, perhaps most famous for his role in the Infinity Saga storyline of the early 1990s. (The Infinity Gauntlet itself, which gives the wearer godlike powers, even makes a brief appearance in 2011's Thor). However, apart from being a power-mad despot of galactic proportions, it's still unclear what role Thanos will play in the Marvel Cinematic Universe. One possible connection is that the character rules a massive empire in Marvel's Ultimate comic universe (from which the MCU draws many of its characters), and fathered a son in Ronan the Accuser. Ronan will appear in Guardians later this year played by Lee Pace.
As for Josh Brolin, this is only the most recent comic book property he is attached to. Brolin is already set to play Dwight in Sin City: A Dame to Kill For, which hits theaters this August.