I'm a librarian who loves anime, manga, and reading a wide variety of genres.
This is not a trilogy you can read out of order – if you haven't read the first two books, I highly recommend you do so before reading Ancillary Mercy. And if you're not a fan of the pacing in those books, you probably won't be a fan of it in this one. Also, a note: I've found that I need to reread these books in order to catch everything going on. I haven't reread Ancillary Mercy yet, although I definitely plan to. I'm just so far behind on my review writing right now that I decided I wasn't going to wait to write this one too.
Ancillary Mercy begins not long after the events in Ancillary Sword. For some perspective: Queter hasn't been interrogated yet. The part of Anaander Mianaai that is angry at Breq has taken Tstur Palace and has almost certainly sent a portion of herself after Breq. Meanwhile, someone who may be an agent of that part of Anaander Mianaai is interfering with the efforts to repair the Undergarden and allow the Ychana who lived there to go back to their homes.
It's tough to know what to say that wouldn't count as a spoiler. However, I feel I should also mention that readers finally get to meet the ship from beyond the Ghost Gate, a Presger Translator makes an appearance, and there is “AI stuff” and “messy relationship stuff” (“romance” isn't really the right word) galore.
When I first started this trilogy, I was a little disappointed that there wasn't as much AI stuff as I would have liked. Yes, Breq was an AI, but she spent a good chunk of Ancillary Justice pretending to be a human. The bits with her as a ship were nice, but also incredibly painful to read because it was clear that everything was going to go horribly wrong, would have to go horribly wrong for Breq to be single-bodied and alone 20 years later. Ancillary Sword did a better job of scratching my AI itch, giving me Mercy of Kalr, Athoek Station, Breq, and Sword of Atagaris. The variety of AI characters was very nice, even though I didn't necessarily like them all (Sword of Atagaris, I'm looking at you).
Ancillary Mercy was even better in that regard, and not just because it added a new AI character. The previous books has made it clear that the AIs were essentially slaves of the Radch. In order to secure her position, Anaander Mianaai kept control over the AIs by learning who they each loved the most, so that she could use that information against them if necessary. She also had access codes that could allow her to force any AI to do as she ordered, even if those orders threatened the lives of the AI's crew/residents and the particular people it loved the most. In this book, Breq did something about that.
I won't go into much detail about how she accomplished it, because even this much feels more spoilery that I'd like, but the results made me hope that Leckie plans to write lots of other books and stories set in this world. Considering the nature of Anaander Mianaai's existence, I was skeptical that Leckie could satisfactorily deal with that aspect in only three books. Impressively, she managed it, for the most part.
The Lord of the Radch wasn't completely defeated by the end of the book. There were still lots of things that needed to happen, and things that could go wrong (the Presger could throw an enormous wrench in the whole thing, if they wanted), but I could easily imagine Anaander being powerless in a few years or decades, however long it took for the events in Athoek System to trickle through to the rest of the Radch. If there was one thing that disappointed me about this book, it was that this aspect of the trilogy ended much more...quietly...than I had expected. The closest things Ancillary Mercy had to big space battles were Anaander's disastrous arrival at Athoek Station (not so much a battle as a horrified “oops”) and Breq's efforts to destroy as much of Anaander's incoming fleet as possible. I'm not really that disappointed, though, because an enormous and dramatic battle would probably have felt out-of-character for this trilogy.
I've saved the best for last: the relationship stuff. This was so tremendously perfect that I could write pages and pages about it. However, that would involve great gobs of spoilers. So I'll just say this. I shipped Breq and Seivarden in Books 1 and 2 but was also afraid of what might happen if Leckie turned it into a sexual relationship. I read fan theories that seemed plausible but that would probably have depressed me if they had become canon. I desperately wanted the relationship aspects of this trilogy to be resolved in a satisfactory way, but I was also very nervous that everything would go horribly wrong. It didn't. It was wonderful in ways I hadn't expected and hadn't realized I wanted. Unfortunately, now I want more, and I have no idea where I'm supposed to get it. I hope Leckie revisits these characters at some point, although I think I'd also enjoy seeing how Breq's matchmaking efforts with Sphene and [redacted] turn out.
I really wish I had read Books 1 and 2 closer to Ancillary Mercy's release date, because the wait was excruciating. However, it was worth it. I loved this book and the trilogy as a whole, and I hope that Leckie has lots more planned for this world.
I was tempted to give this 4.5 stars rather than 5, because of my mixed feelings about the Anaander Mianaai aspect, but there were so many other things that I absolutely loved that it didn't seem right. So, 5 stars it is.
(Original review posted on A Library Girl's Familiar Diversions.)