The novel. Not the manga. The manga is (loosely) based on the novels. The manga is highly stereotypical and far less interesting unless you're completely new to the world of anime. Well, maybe they got a new producer or something since the samples I saw...
Why does it matter which one I say it's from? One follows the other anyway. (Unless perhaps you haven't read up to v8 and 9 in the manga? As it is; I haven't read the novels.)
All I'm saying it that I, personally, think the movie is well worth watching.
