This is book five of The Realm of False Gods series. I do love this series. And I give this book four stars. The concept is fascinating, the sense of place is well defined, and the characters are varied and engaging. But (you could see the "but" coming, couldn't you), there does seem to be a continuity issue with these books. For example, some characters seem to be unaware of abilities they were able to wield in previous books. It may be that the timeline has overlapped, but that is unclear in the storyline.
The author acknowledges in the author notes that he did not write these books in order. This novel is the one he wrote first, so the previous novels had to be fitted in, and that, I believe, is where the problem begins. (Five prequels?) For example, in this novel the mortal and immortal realms are well defined and known by the characters. In the previous novels, they're only hinted at, which would be fine, except that there is no transition or explanation as to how or why the characters came to their knowledge. Just as Mr. Higgs has needed proofreaders to check spelling and grammar, in this series he needs a continuity person to check that the story flows without fits and starts.
All of that being said, I still recommend this series. It's a great story, even if the presentation is uneven. (Maybe it will be better in the film version?)