"The Hundred Thousand Kingdoms" is told from a first-person point of view, with voice of Yeine. Yeine is a granddaughter of Dekarta Arameri, a supreme ruler of the world. Now it is important to introduce the setting a bit. Several hundred years ago, a war started between Nahadoth, god of chaos and dark, and Itempas, god of order and light. Itempas was and punished Nahadoth, with some of his offspring, to server as slaves to his highest servant, priestess Arameri, and her successors. The Arameri, using gods as formidable weapons, managed to conquer the whole world set a government with them at the top - and becoming decadent and eccentric (as in polite word for crazy) in the process. Now let's get back to Yeine. Some twenty years ago her mother Kinneth, a designated heir and very proper Arameri (cruel and manipulative), abdicated and left court to live with her lover from backyard and barbaric land of Darre. After her sudden death, Yeine is called to court by her grandfather where she is suddenly pronounced as one of three potential heirs, together with two her cousins. To become a real heir, one of them must defeat and force another of them to accept them as heir - which usually includes the death of third one. So Yeine is left to learn fast about gods, history, her family and manipulation, because the last hour of her grandfather Dekarta is coming fast.
I must admit that Jemisin came up with some really great concept and setting. The gods-part is based partially on Hinduism (light-dark-shadow; order-chaos-balance), but also on old Greek myths, where gods have human personalities, are petty and vengeful, mingle with humans and so on. But on the other hand, she finely succeeds in making Nahadoth and others strange, inhuman and magnetic. This is also true for the Arameri and the whole court - they are not someone you would want as a family, but they are intriguing. I did have a filling that she maybe should have made them even stranger - being a member of family whose word is absolute law on whole world should result in some strange personalities. Also, is this Arameri having access to ultimate weapons some pun/metaphor with Americans and nuclear bombs?
Plot is an interesting mix of power struggle, detective story and exploration about Yeine's family and history. Much appeal of it comes from the narrator-type storytelling. Yeine is not exactly an unreliable narrator, but she is prone to wandering and skipping. The pace is fast and intense - Yeine is not really a passive person. Expect some big turn-overs at the end - not something you will expect when you start reading.
Other characters are also interesting, although I could appreciate more development, but since this is a first-person POV, it can be expected that all focus will be but on Yeine and her interests. Sieh's character seems quite familiar, but I can't remember from where. I am intentionally skimming on descriptions because this would result in spoilers.
Jemisin's writing was fast and good. There are some violent and some sexual scenes, but nothing over the board. I liked the Nahadoth/Naha thing. There was some humor, streaming from Yeine's observations, but this is in general a dark book, I think.
Although I had some great time with this book, there are some small surprises. When I bought the book, I expected a first part of epic-fantasy trilogy. But this is not really a trilogy. "Hundred Thousand Kingdoms" is a self-contained book with definite ending. Two sequels, "The Broken Kingdoms" and "The Kingdom of Gods", are taking place in the same setting and after these events, but there is nothing in this book that asks for sequel. And second thing, the book was really short: I finished it in two afternoons and one evening.
But these are not serious objections, just misplaced expectations. "The Hundred Thousand Kingdoms" is a very good and unique book. I would recommend it to everybody - it has unique setting, clever and interesting narrator/main character and some fast and surprising plot.