Toriaezu, Yarimashou

"Please, don't stay in my heart..." Ilya is a military prostitute known for not sleeping with customers, as she can calm her magical powers by singing. Though she grieves for the loss of her homeland, she is determined to remain cheerful and live a strong life. One day, she receives a secret request from Cian Asberg, a ruthless magician known as the "Silver Ice Knight." The higher the attack power, the more likely the magical power will go out of control. While soldiers usually sleep with prostitutes to calm it, Cian is famous for not sleeping with prostitutes. Wondering why she, a prostitute, would be there, she visits Cian, only to find him breathing in pain. This is a pure and heartbreaking love story of two sides: a lonely prostitute who cannot be honest with herself, and a knight who hides his purity behind a cold mask.

(Source: Kadokawa, translated)