Basically, The League of Shadows is an ancient organization that tears down cities when corruption starts to run rampant. They justify it as helping the betterment of the world. Rhas Al Ghoul (I know I messed that up) is the apparition that appears to Bruce while he is in the prison. I'm a comic book nerd, so my one complaint about the movie is that it completely left all of that out (or if it was mentioned, I didn't think it made a big enough emphasis on it). So I felt like the people with me probably didn't get that either. In Batman Begins, they talk about how the League of Shadows destroyed Rome and some other places and now it is Gotham's turn.