I have so many feelings.
3.5 rounded to 4 stars.
Though Empire of Gold, is too weighed down by its extensive mythology like earlier volumes and only resolves with several deus ex machina, it weaves enough elements from the prior books (along with a number of big reveals) to be a reasonably satisfying conclusion to the trilogy.
The book picks up immediately where Kingdom of Copper leaves off, so I recommend rereading KoC if it's been awhile or at least leafing through the glossary in the back (which I only found after finishing the book).
Daevabad is in chaos following the attack from Manizheh's forces. Nahri and Ali find themselves stranded in Egypt. This results in a bifurcation of the plot with POVs from Dara in Daevabad and Nahri and Ali, who are traveling together. The non-Western setting is what initially drew me to the book (and in my opinion is the star of the show), and it's still present here, especially with the sumptuous descriptions of buildings, clothing, and food.
To me, the main struggle in this book is about identity-- primarily Ali coming to terms with his mysterious connection to the marid (and more subtly, learning how to work with and understand others, continued from the last book) and Dara's internal war with his conscience and the words of his Banu Nahida. After finishing the last novel, without spoilers, I think it's clear that Dara and Ali are set up to be counterpoints to each other. They're both confused men with troubled pasts (albeit VERY different scales of trouble) who grew up in extremely hierarchical settings where they were expected to obey. They both struggle with who they want to be and the roles others put them in. They both take long journeys with Nahri, and they both fall in love with her.
Some other themes from the earlier books also are emphasized:
Violence begets violence
Two wrongs don't make a right
No plan survives contact with the enemy, and your enemy is likely to be just as motivated and clever as you are
Despite personal risk and futility, we must stand up for what we believe is right
I really struggled to keep up with various groups and political entities in the first novel, and it gets even worse in #3-- there aren't more players, but there's no refresher exposition and the glossary in the back is of limited use since it doesn't focus on just the key important characters. I really wanted a short summary at the beginning!
I found myself rereading City of Brass and Kingdom of Copper as soon as I finished Empire of Gold because I felt like I wasn't doing justice to the book as a reader with so little remembered context. The refresher certainly helped-- I was able to let the unimportant names flow past me like the world-building asides they really were. Rereading the books also made me absolutely fall in love with the setting again.
The experience of rereading also gave me fresh insight on Dara as a character. Most of the fan fiction on AO3 is devoted to him and Nahri, which baffled me. When I originally read CoB, Dara seemed like a deconstruction of your typical alpha male romance hero. Not only is he bad at communicating, he's REAL bad at it. He's beautiful, but also a jerk who's rather racist. He doesn't just have a past, he's responsible for slaughtering thousands of innocents. In short, ideal male lead on the surface, but highly troubling at every level.
As I reread the trilogy, I realized how much we see Dara struggling to do the right thing but always making a critical mistake somewhere-- believing what his masters tell him, not turning his counsel into action, not taking critical players into confidence, trusting a suspicious ally, and so on. Most of these issues and most of the positive things he does are based on the same thing: loyalty before all. It means he obeys his masters even when he vehemently disagrees, but it also means he'll rush into danger to save one of his soldiers. He truly wants to fix the world but keeps doing the same thing. The definition for insanity is of course doing the same thing over and over and expecting different results. It makes it painful to watch, and I don't think we get the satisfaction of seeing Dara learn from his mistakes until very late. It makes him a tragic, frustrating figure-- we get to see him struggle internally, but his attempts to prevent further wrongdoing are never enough.
To contrast, our very first interactions with Ali in book 1 show he's already willing to compromise his loyalty to do what's right. While he refines this and mellows a bit during the books to be less of an ass, I don't think we see nearly as much internal character growth. The text really works hard to endear him to readers, and some elements were frankly charming (like in Kingdom of Copper where he includes a beautiful Egyptian-themed office for Nahri in the hospital). I'm not opposed to a main character having a flat character arc, but it's unsatisfying when compared to Dara.
So, in conclusion, I don't know. I love the setting. I really enjoyed a lot of the characters. I'm still frustrated, in large measure because there's so much good stuff here. Perhaps too much good stuff. But I have immense gratitude to the author for introducing us to this world, giving us an ending, and setting me off on an honestly rather pleasurable analysis paralysis.