A neat beer and pretzels and necromancers and lesbians and spaceships story that is great fun but doesn't quite rise to the level of greatness. The story is FanFiction++; it can be tropey and fan-servicey but does so with a quality that puts it above what you might find on some random fan fiction site. So, some more details. The protagonist (Gideon) is a Korra type character; jockish, kind of a doof, enjoys fighting. She's the unhappy ward of the Ninth House, one of the nine houses of Necromancers in the Empire. Her companion/antagonist is Harrowhark, the scion of the decaying Ninth House, an ultra-goth and ultra-skilled necromancer, sort of a female Raistlin character. Together they've been summoned by the !Necrolord Supreme! to a special conclave, where the scions of all nine Houses and their cavaliers will be meeting. The meeting turns into an ambiguous escape room/murder mystery, where the different groups need to figure out why they have really been brought to this island complex, what lessons or secrets they are supposed to learn, whether they should be competing or cooperating on these mysteries, and how the place they have been brought to plays into the history and metaphysics of their empire. It's a great dynamic; each of the House's has its own outlook and specialized skills, and you end up with a cast of ~20 characters who are all distinct and memorable and interacting and problem solving in different ways.
So, overall the book was great fun. It did have a few issues though, which keeps me from putting this at the level of something like _Nine Fox Gambit_. One is that due to the number of characters, the primary characters didn't receive quite the level of development that I would have liked. E.g. I would have loved to see more of the interactions between Gideon and the Thirds, or Gideon and the Seventh. Instead these things are given a paragraph or three, but you don't get the fully developed and elongated and realized relationships like you would in something like _Persuasion_, where the majority of the book is focused on just one pairing. Similarly, Harrowhark's character gets short shrift. At the start of the book Harrowhark is a force of nature, and it is only near the end of the book where she starts talking more and we start peeking into her PoV. However, once you start learning more about her, she doesn't seem to have the sort of personality which would produce the actions from the first half of the book. I feel like Harrowhark should have been something like the protagonist of _The Wasp Factory_, but her actual personality once you get to know her isn't nearly fucked up enough. Finally and most nigglingly, it wasn't entirely clear how some of the magic/necromancy aspects of the story functioned. E.g. 90% of the way through the story, someone gets a Hold Person spell cast on them, but it was not clear like on what basis the spell is working. And I feel like I should have understood that, as well as some of the larger metaphysical aspects of the story, better. I'm not sure if that's a failure to comprehend on my part or a failure to explain/design things on the author's part.