Review: 
 Protagonists: Join demigods, Jason, Piper, Leo, Percy, Frank, Hazel, and Annabeth as they set out on one final quest to stop Gaea from rising and destroying the world. Helping them in their quest, yet heading in the opposite direction are Reyna and Nico, who are trying to mend the rift between the Roman and Greek demigod camps to help deliver proper back-up to out seven heroes in Greece. I loved every minute that I got to spend with these characters and while I know that this book is the last, at least for a while, their growth not only in this book, but in the series as a whole has been both astonishing and wonderful to read. I loved how each and every character in this world is unique and while their are some characters that fade into the background, most stand out so well and really just bring a great amount to the story. 
 Romance: While romance wasn't anywhere near a focal point of this book, it does drive certain characters, such as Leo Valdez, to give it their all to stop Gaea once and for all. It seems like in the end almost everyone had someone there for them, it was weird how that worked out, but it was nice to see these characters that I've loved since I was like fourteen end their stories happily and have that sort of happily ever after moment. 
 World-Building: So the world-building in this book comes from more then just how much of the world we get to see but from how the mythology is grown and twisted from the original myths that many of us may already know. While there wasn't too much deviation from classical myths, at least not that I noticed, but the things that were a bit twisted or different made for some amazing plot elements. One thing that I really liked seeing was Orion, the Greek hunter, who eventually found himself as a constellation in the night's sky, actually being a Giant of Gaea meant to oppose Artemis and Apollo. In addition to twists on Greek and Roman myths, we also learn more about certain characters such as Reyna, who we find out much more of her backstory and learn what sent her to Circe's island in the Sea of Monsters. 
 Predictability: Going into this final book, I had many, many expectations and while most of the were met, there was one, just one that I was kind of disappointed by. I had prepared myself for something catastrophically terrible to happen, just in the event that it did, I found that this book ends much happier than I had anticipated, and while that's all well and good, I felt that I was sort of robbed something terrible happening. Many things in this series were unpredictable, but that was weirdly the most unpredictable of them all. Am I an utter masochist for wanting a sadder ending? 
 Ending: Speaking of the ending, while I was (weirdly) a bit disappointed that it didn't end worse than it did, it did actually tie up most if not all of the loose ends of the series. While Percy Jackson and the Olympians left things off fairly tied up there were seeds sown to lead into this series, however at the end of this book everything was nicely tied up. We got to hear about how our heroes futures might go and it gives a great sense of closure for the series as a whole. However there is just ONE thing I have a problem with and it was that the last chapter should have either been longer or there should have been just one more chapter. Not that I wasn't ready for the series to end, but that there was just one more thing that needed to be resolved and it wasn't something big enough to lead into another series, at least I don't think it was. 
 Rating: 
 Overall, I found this to be a very well executed end to this series. While I saw a few people point out that certain heroes such as Annabeth and Percy don't get their own chapters in this final book, I actually didn't even notice until someone pointed it out to me. I felt there was enough of these characters, even seen through other's eyes that them not having their own chapters, while preferable to many, wasn't really needed. I can't wait to see what Rick Riordan has up his sleeve next, *cough* Norse Mythology *cough*