Review: 
 Protagonist: At the end of the previous installment Mason Starling has the Odin Spear in her hand as the Fennrys Wolf lays dying at her feet. Now the fate of the world literally hangs in the balance of one choice that only Mason, a chooser of the slain, can make. Honestly, at this point Mason's a pretty well developed character at this point and this book is really about her using what she's learned and her experiences from the past two installments to find a way to end Ragnarok before it ever begins. Does she had character development, sure, but it's not really something large and easily seen, but more subtle things that change how she acts and the choices she makes. 
 Romance: So, yes a lot of this book is dedicated to the relationship between Fenn and Mason, and while that is all well and good, as well as one of the most mature romances I've read in a YA series, I don't want to focus on that so much. I want to talk about Callum and his feelings for Mason, and Heather's feelings for him. While not as big a part as the Fenn/Mason romance, the romance between Heather and Callum is actually very compelling after a few things are revealed, unfortunately these things aren't truly revealed until very close to the end, but still it puts Callum's at times obsessive love for Mason and Heather's conflicted feelings into perspective. 
 World-Building: So going into this book I had thought Ragnarok had just begun and that the majority of the book would be our heroes trying to change the outcome of the Nordic apocalypse, instead all the pieces to Ragnarok are there they just haven't been put into place, and instead it's up to our heroes to stop Ragnarok before it can ever begin. While the apocalypse style action I had expected and there was light shed onto the yet to be explained mysteries, they just happened in ways that I hadn't expected. This was by no means a bad thing, it only meant that either I didn't remember all that much that I had thought of the previous installment or that mixed with what I couldn't remember of the first book meant that I went in with different expectations. 
 Predictability: For the most part there were a whole lot of things in this book that I saw coming, even a fairly large twist at the end I had expected to happen, but there were some great moments that I could have never seen coming. There are characters that we meet that I had never thought we would, and how our heroes deal with the coming apocalypse is very ingenious, especially how Mason deals with her unbelievable tool of a brother Rory. 
 Ending: As far as ends of series go, this one was pretty amazing, while not quite everything was neatly tied up in a bow, most everything is. The final battle as I said above was absolutely spectacular, just like the myths and prophecies, not everything is as it seems and there are always more than one way to end a story. That rings true in this ending especially as Mason's story ended, I'm interested to know if the author has any plans on at least one more trilogy set in this universe, granted I haven't read the Wondrous Strange series yet, but I'm just not fully ready to let go just yet. 
 Rating: 
 This series has taught me a lot about Norse mythology and is one of the few series I've seen to incorporate more than one classic mythology into their world. I'm sad to see it go, but at least it ended with a happily ever after of sorts. A brilliant end to a brilliant series!