Iron Widow()

In the world of Huaxia, humanity's last defense against invading aliens lies in the Chrysalises, giant transforming robots piloted by a boy-girl pair in which girls disproportionately die, their life forces drained by their male pilots. When eighteen-year-old Zetian volunteers to be a pilot in order to get revenge on the ace male pilot responsible for her sister's death, her unexpected revenge makes her a state target at the same time she may be its only hope.