The Poppy War (R. F. Kuang)

The author of this book is a finalist for for the "not-a-Hugo" Campbell Award, give to "the best new writer whose first professional work of science fiction or fantasy was published within the two previous calendar years."

Fang Runin ("Rin") is an orphan, adopted mainly to do housework for a family with no daughter. Faced with a marriage to a suitor whose main qualification is the wealth he'll bring to her foster family, Rin takes one of the few avenues available: she studies herself nearly blind and demented and manages to snag a position at her nation's elite military academy, Sinegard.

Unfortunately, rather than being impressed with her determination and hard work, most of the faculty and students at Sinegard despise Rin for being a peasant. Some actively want her to fail out. Her situation becomes better in some ways and rather worse in others when she pledges herself to the eccentric Lore Master Jiang rather than one of the more respected masters. Jiang detects and encourages Rin's hidden potential for shamanic magic—"lore." She begins to think she may have found a place.

Meanwhile, the Empire is threatened by a powerful invader, the Federation of Mugen. When the Federation makes its move, Rin and the other Sinegard cadets have an all-too-real practical example of the benefits and limits of their military education. As many have noted, this is where the story takes a very dark turn. Kuang uses the accounts of real-world atrocities such as the Nanking Massacre as the basis for a series of horrifying scenes in which Rin and her new comrades, a band of intriguing misfits with unusual powers, do their best to stem the tide. One of the effects of all this is that Rin is finally able to tap the core of her powers.

The result is not pleasant. Raised with little if any sense of compassion or ethics, accustomed to having to push herself to the utmost for results, and lacking any superiors whom she respects, Rin starts to become a monster.

I will probably want to continue this series if only tp find out whether Rin ever comes back across the moral event horizon. But this is not a light-hearted read.