So far, there have been 4 volumes already released, each with about 4 or 5 chaps.
There are an additional 3 chapters release for Issues of G-Fantasy. Those are raw, so I have no clue what's going on, except there's quite a bit of blood...
Here's an image of one of the releases...
EDIT:
I've gotta say though, Oz is slowly becoming one of my ideal male lead characters