**WARNING MAJOR SPOILERS AHEAD**
I could not have asked for a better conclusion to this great trilogy. I was beyond emotional reading this book. I loved how this book really instilled the idea from the first two books that no one is just good or bad, and good people can do terrible things in the name of what they believe is a good cause. I really liked the way that Nahri and Ali's relationship developed in this book. In the first two books, I wasn't really rooting for them to end up together, in the first Ali was more morally gray so I didn't want to root for him at all, in the second I liked him as a character, but couldn't get behind a romantic relationship for him and Nahri. This book really got me behind them. The way they built their relationship on a solid foundation of friendship and the fact they were both more concerned with saving their people and doing what's right rather than getting it on was really admirable. I also think that showed how much they really cared for each other, they didn't expect to survive and didn't want to start a relationship only to die. Their fierce loyalty to each other, which is built on mutual respect and common goals is an admirable way to build a relationship and a good example. 
The way Dara's character was handled in this book was also fantastic. Dara had to work through a lot to figure out what he really wanted and who he wanted to support. He had complete loyalty to Manizheh which stemmed not only from his familial ties with her but also from an obligatory loyalty due to her saving him from slavery and from death. He also believed in her cause, he believed she was the best person to save their people from a tyrant king. One of the most heartbreaking moments of this book is when Dara begins to stray and Manizheh does the most abhorrent thing she could, enslaving Dara. Reading that chapter was so difficult because not only did Dara lose his free will, not only was he forced to murder countless people he knew were innocent including children, he had been brought back to the worst time in his life. Most of his character trauma draws from his experience as a slave. From the beginning of the trilogy, we see how his enslavement caused him so much pain, and the one person he served loyally, who he trusted, betrayed him and took away the most important part of him. It was truly heartbreaking to read. This only got worse when Manizheh betrayed her daughter by giving up the name she herself didn't even know, so she would be enslaved as well. Nahri was abandoned by her family, an outcast forced to bring herself up on her own. She was given a glimpse of who she was and her people only to be taken advantage of by a terrible man who manipulated her and controlled her life for six years. She finally is free of him and her mother sells her out for a small bit of power. Nahri claiming her name for herself and freeing herself was one of my favorite parts of this book because it really shows how much she has been through. She no longer needs to be told who she is, she chose her name and is the only one who can say what she can do. I actually suspected Manizheh wasn't really Nahri's mother for a while. For me, it didn't make sense why Manizheh would treat Nahri so poorly when she would've been the one to abandon her to the humans. Which even more doesn't make sense, especially since Nahri still had her powers. Why would Manizheh have taken Jamshid's power but not Nahri's. Not to mention, Manizheh was so in love with Kaveh, it didn't make sense for her to have a child from someone else. I really liked learning Nahri's history, and while it was kind of just an info dump, it really tied the story together. 
Finally, I absolutely loved the end of this book. I am a sucker for a happy ending and this book really did a perfect job ending the series. First of all, this ending felt well deserved. With what we went through in this book, if the ending had been sad I don't think I would've survived it. Not only that, but the ending made sense and was built up well throughout the series. Each character had an appropriate conclusion. I loved how Dara wasn't just killed off as a villain after everything. He wasn't forgiven by the masses, which is good, but he is able to do some good and feel like he is atoning while still finding some happiness for himself. I especially loved how he and Nahri got to have a final goodbye. It was clear Nahri always held Dara in her heart and allowing them to part amicably felt right. I especially loved Nahri's ending. So many stories make their female lead have to choose between her power and her dream, and I love that Nahri was able to have both. She is a powerful leader who didn't have to sacrifice her strength to be happy, plus she gets to fulfill the dream that she's had from the very beginning. Not to mention she has a cute little undefined relationship with Ali and even gets a family in the end. With all that Nahri (and the readers) have been through, seeing her get a joyful end is all I could've wanted and it makes this book spectacular.