It could have been much better. I felt, overall, rather let down by this book. Sure, it wrapped up the story threads from the last two... But it could easily have been done in the second novel. This book felt almost entirely unnecessary. It seemed like it was stretching to fill pages, since a Trilogy of the Blood Curse needs a thirf book. But most of it was redundant interactions, quotes of prophecy, scenes of travel, and some general nonsense thrown in for good measure.
The "reveal" takes up the last third of the book. It was, to me, exceptionally anticlimatic. Those last hundred pages were more-or-less a chore to trudge through.
Added to this is the fact that its interwoven with the Grails Covenant trilogy, which I have yet to read. There are parts referenced in here that I assume take place in that trilogy, but left me generally clueless since I haven't read the other books.
If you've read the other two books and want to see the conclusion to the trilogy, you can pretty much skip to the end unless you want to read The Wacky Travels of Owain Evans.