This is a series.
Rin, a war orphan raised by opium smugglers in the Empire's poorest province, tests into Sinegard, the elite military academy, and finds a place where every other student has been trained for it since birth and despises her for her accent and her colour. She discovers she can reach a vengeful god through shamanism, and when a third war with the Federation of Mugen arrives she has to decide how much of herself she will hand over to win it. Kuang builds the war directly on the Second Sino-Japanese War, the Rape of Nanjing included, and does not soften any of it.