Joblo brings us the following:
According to our source the main villain will in fact be Ronan the Accuser, the ruler of the alien race known as the Kree. Ronan has fought the likes of the Fantastic Four, The Inhumans, and Guardians of the Galaxy in the comics and is a mainstay of the Marvel cosmic universe, so it's well in line for him to be featured as the main villain, especially with Marvel looking to expand it's cinematic adventures to the far reaches of space. Could this be a lead-up to the Kree-Skrull war in THE AVENGERS 2? It's anyone's guess, but Ronan is certainly a formidable threat and a solid lead villain for GUARDIANS OF THE GALAXY.For those not familiar with who Ronan is, Wikipedia says:
Ronan the Accuser is a fictional character that has appeared in numerous comic book series published by Marvel Comics. A member of the alien race the Kree, he exists in Marvel's main shared universe, known as the Marvel Universe. Ronan first appeared in Fantastic Four (vol. 1) #65 (1967), and was created by Stan Lee and Jack Kirby. While the character spent most of his published existence as a villainous figure, over time Ronan has slowly become more noble and heroic.