Iron Widow (YA)

Love cannot save me. I choose vengeance. The boys of Huaxia dream of pairing up with girls to pilot Chrysalises - giant transforming robots that battle aliens beyond the Great Wall.

It doesn't matter that their female co-pilots are expected to serve as concubines and often die from the mental strain. When 18-year-old Zetian offers herself up as a concubine-pilot, her plan is to assassinate the ace male pilot responsible for her sister's death. But after miraculously surviving her first battle, Zetian sets her sights on a mightier goal.

The time has come to stop more girls from being sacrificed.