Senpuu no Rust: Gyakkyou Shoujo no Youhei Life to, Burai Eiketsu-tachi no Seihou Kokkyou Senki

Rust, a 17-year-old girl, is still a fledgling professional mercenary. She chose this path to earn money for the treatment of her sick mother. Many trials await a girl in a world where men who boast of strength clatter their arms. However, Rust will never give up, and with her special skill "Seijutsu", she will seize her new life! The story of a girl mercenary and her friends, a story of growth and warfare, begins here!

(Source: Brave Bunko, translated)

Note: Grand Prize winner of the 2nd Hifumi Shobo Web Novel Awards.