It actually is more like who ... but let's not get ahead of ourselves. Not that the pacing of the movie would have you in that mood. So if you like fast paced told stories, you might want to look somewhere else. But if you are into stories told slowly and soaking in the mood and the ambient and everything else, this is exactly for you.
Now the fantasy (or fairy?) element of it all is there, but it is quite dark. And while not every question will be answered (remember that and don't blame the movie for it), you will have a lot of tension and a kid that has to physically cross to the other side (analogies and all) - what will he find and will we be able to make sense of it? Well that is for you to discover and to draw your own conclusions ...
Now the fantasy (or fairy?) element of it all is there, but it is quite dark. And while not every question will be answered (remember that and don't blame the movie for it), you will have a lot of tension and a kid that has to physically cross to the other side (analogies and all) - what will he find and will we be able to make sense of it? Well that is for you to discover and to draw your own conclusions ...