From what we know of this Chatacter (implyed by the name also) he is the "bad-guy," and "main target" of the film. Even though Cillian Murphy said that he wouldn't be playing another villian after Batman and Red Eye, he seems to have choosen this role. In a recent interview, he says that Nolan (The Director) let him decide which character he wanted to portray. Inception is still pretty much under wraps (like most of Nolans films) But if you join the link which is always up-to-date, you and I will soon learn more about this highly-anticipated film!