Saikyou no Youhei Shoujo no Gakuen Seikatsu: Shoujo to Shoujo, Kaikousuru

A girl named Sierra, raised by the famed mercenary Ains Worker, is sent to a royal school in the capital to learn how to live normally. Struggling to adapt after a life on the battlefield, she uses advice from Ains' notebook to navigate school life. Despite her efforts to remain unnoticed, her abilities draw attention. She befriends another girl named Aruna, who helps her avoid trouble. As their bond grows, Sierra remains unaware that Aruna is involved in a scheme related to the throne's inheritance.