Quick-take: A typical, though decent, mid-series filler book.
I almost dropped this one to a 3. This is the filler book I saw coming. I was surprised it happened in book 3 instead of book 2.
Warning, some subtle Book 2 spoilers here, though nothing remarkable...
A significant amount of time was spent resolving the major plot change that occurred in book 2. That consumed 80% of the book. There were lots of political maneuvering and failed assassination attempts. That's all entertaining, but knowing the main protagonist is not going to be killed (still have more books in the series) takes a bit away from it.
We learned a lot more about Cheslea, the great shade of Bethesda. Surprise, she really isn't just a ruthless killer -- though that was already established in previous books. However, we didn't learn quite enough for it to really matter in this book.
Marci got more powerful, though we saw that coming in the previous book. How much more powerful is hard to guess. 2 more characters were introduced that are only mildly interesting.
Really, overall, nothing truly remarkable happens in this book. Julius doubles-down on his extreme earnestness and pacifism. Many times in the book I want to smack him and tell him that sometimes murdering people/dragons really should deserve an appropriate punishment. He is going to be treated like a doormat. However, the pacifism keeps working out in his favor... to the point it is really hard to be believe.
This was a filler book, but all the content was well-written and entertaining, thus I score it a 4. At the very end, an important major plot point was finally closed but the fallout is left open for the next book. Annoying, but I was already planning on picking up Book 4.