Iron Widow - Xiran Jay Zhao

The boys of Huaxia dream of pairing up with girls to pilot Chrysalises, giant transforming robots that can battle the aliens that lurk beyond the Great Wall of China. It doesn't matter that the girls die from the mental strain.

When 18-year-old Zetian offers herself up as a concubine-pilot, it's to assassinate the ace male pilot responsible for her sister's death. But when she gets her vengeance, it becomes clear that she is an Iron Widow, a rare kind of female pilot who can sacrifice males to power up Chrysalises instead.

To tame her frightening yet valuable mental strength, she is paired up with Li Shimin, the strongest male pilot in Huaxia, yet feared and ostracized for killing his father and brothers. But now that Zetian has had a taste of power, she will not cower so easily. She will take over instead, then leverage their combined strength to force her society to stop failing its women and girls. Or die trying.