This won't be much of a review, but I just have to gush a bit. :-)
I loved this!
The world, the characters, everything. Especially Augus and Gwyn. *sigh*
True, it is a bit confusing at the beginning, since there is a prequel that explains some of the background (the prequel is Legend of the Guardians fanfic, but this is mostly original characters; in fact the author is working on making this completely original). But, things get cleared up soon. And then it becomes amazing!!!! :-)
Highly recommended! But, before going into this, do read the warnings on AO3. The author is pretty good in listing all of the possible triggers.