My opinion of this book is a weird one, because up until the very end, I was largely disappointed by this finale. I blame this largely on the pacing of everything, and had this been fixed, this book could have very easily been a 5-star finale (which is very tough to do!)
Another big issue going into this one is that due to the second book, I went in only really invested in Anton and Jude. I'd grown disinterested in the other POVs, so a lot needed to happen in this book to make me fully invested in every aspect again. And I had high hopes, since the second book ended with so much chaos happening, but with all the characters in the same place again. Unfortunately, the first 25% of this book is them once again being split up and trying to team back up (sort of, it's more that certain individuals want to save other certain individuals, and it turns out they all happen to be in the same place that they need to be saved from). It picked up once again after, when they're teamed up and have a solid plan, but when that plan unravels... the team splits up again. This constant splitting up means that over the course of this series, the group doesn't actually spend all that much time together, which makes some of their intense positive feelings about each other ring false, except for the few pairings or trios that did spend the majority of the books together (Illya and Ephrya, Anton and Jude, Ephyra and Beru, Beru and Hector, Hassan and Khepri). It was only those relationships that ever felt like they had any strength to it, especially since when the groups got larger, they couldn't stop fighting. We didn't see any true camaraderie until the final few chapters, which is where I started to really love this book.
The ending itself is what brought this book to 4 stars, rather than 3. I really enjoyed how it all went down, and it gave me back the same intense emotions as the ending of book 1 did. While the resolution to the overarching problems could've been better woven into the rest of the book, instead of one side character just spouting the solution on their deathbed, the solution itself did a good job of tying the story together, and further tying the characters themselves together as well. There was also enough sacrifice and change that it didn't feel just, miraculous that they ended up winning. It was a solid ending to the story overall, and I especially loved the extended epilogue. While it was an overall happy ending, it wasn't too perfect of a happy ending, and it showed how much work the world and characters still had to do, while still giving them some peace and respite after the hard events of the book.
Overall, there was a lot of potential in this series, and while I did enjoy it a lot overall, issues with pacing and character relationships (more so in the overall group rather than on an individual level) made the series not as great as I'd hoped. Anton and Jude were excellent, though, and their ending (and the lead up to it) made me cry so many times. I'll definitely be trying whatever this author writes next, and hope the issues I had with this series are resolved a bit more!