I really enjoyed the premise of this series but felt this was a lack luster finish. The story was good but it all felt quite rushed. Especially in the final showdown I felt that there was a lot of mental catch up to get to the same point as Morgan (or maybe I missed things, who knows) and the final standoff/battle was a bit of a let down. 

And poor Medra. She feels like she was created by her mother to fulfil a prophecy and it's true. I felt like this character was just introduced to be a tool at the end. There was no real character development. I didn't feel like I knew her and the rapid aging just felt weird and forced. Like the author go to the end of book 3 and didn't know how she was going to have Perun defeated with Morgan getting a happy ending so she just created Medra to wrap everything in a bow.

 
Overall this was a really enjoyable series.