This series was one of the books on my unofficial "to read" list since right around when exam period began. I'd discovered Aliette de Bodard through her short fiction (her recent novella won the Nebula this year) and, even there, her ability to convey a sense of place and world in her fiction is mesmerizing. She has a sense for what the reader needs to make people-as-members-of-a-culture seem real and she gives her characters a history. One of the things I look for in fantasy is a sense that the world built by the author is one that feels real and plausible and, by grounding her fantasy in Aztec culture, de Bodard definitely succeeds (and, I've said this before, it's so nice to read something beyond badly-researched, generic European setting).
But make no mistake, Servant of the Underworld will be very familiar to fantasy readers. De Bodard's plot draws heavily on the mystery tradition as well as the magical but, in the end, she has told that timeless story of the reluctant hero on a quest to keep things from getting worse and who is asked, in the end, to save both the world and himself. She tells it well and I very much enjoyed reading it. I look forward to the next book in the series and am curious to see whether she will continue to play with old tropes or try something new. I kinda hope for the latter, but would cheerfully read the former as well.
I mean, Aztec fantasy noir? What's not to like?