Becoming the Demon Lieutenant General's Stand-In Bride ~Once An Heir is Born, We Must Part~

In place of her twin sister, Lady Tsukiko ends up in a marriage with Kishi, a young man who rose in the ranks as a lieutenant general. He's also known as the "Demon General" due to his ruthlessness. Since her childhood, Tsukiko has been sickly and deemed as a failure by those around her. After meeti