At some point in Sept of this year, the Ao no Kiseki Special Collection Book will be released. This book will contain character info, story info, world setting data, illustrations, and much more.
Size: B5
Pages: 224, full color
Price: 2000 yen.
More on this as information comes out.
After Crossbell Archive I figured they weren’t going to do one of these. I’m glad to be wrong about that but oh, my poor wallet…