Jim Butcher’s First Lord’s Fury is the sixth and final volume of his Codex Alera epic fantasy series. The series started off a bit slow in the first book, but (like Butcher’s Dresden books) got better as it went on, to the point where it was compellingly unputdownable by the third.
So if you’ve been reading these books, you don’t need me to tell you anything about the last book, because you read it immediately when it came out. If you haven’t been reading them, because you wanted to see if it’d end satisfactorily (not a bad policy at all, when it comes to epic fantasy), well, it did. This isn’t a perfect ending — in particular, there’s a bit of that Tolkienesque “let’s have a giant bighuge battle as a meaningless diversion while two dudes do the important stuff” feel to it — but it’s satisfactory.
I still think Butcher might be better off sticking to the Dresden books (which are better relative to their genre than this is relative to its genre, if you follow), but at this point, I’ll buy anything he wants to write.