Many know of St. Theresa Benedicta of the Cross (Edith Stein), but there are many other female saints who were martyrs during WWII.
Blessed Santia Szymkowiak was a member of the Congregation of the Daughters of Our Lady of Sorrows, also known as the Seraphic Sisters. The Nazis overran her convent in Poznan in Poland in 1939 and Santia was conscripted as translator for the Germans. She had a chance to escape, but chose instead to stay with her community, where she made her solemn vows on July 6, 1942. She would die the following month, having contracted tuberculosis in the prison camp. She wrote in her diary, "Jesus wants me to be a holy religious and He will not be happy with me until I use all my strength for Him and become a saint...I have to become a saint at all costs. This is my constant preoccupation." Santia was beatified in 2002.