Sophie Sawallisch is a Great War veteran and the supreme commander of the Flame Haze Army. Sophie is a woman in nun dress and has a habit of making the sign of the cross even when she does not concern with the clergy anymore. She has a kind heart and is a mother figure to other Flame Haze, thus gaining her famous nickname "Mother Courage". In the war, she showed her elegant potential in strategy and with that, was able to become the supreme commander of the Flame Haze Army.
Sophie meets the Flame Haze of the Nietono no Shana in Eastern Europe and taught the young girl about the manner of the Flame Haze at the present time and how a girl should behave (since she saw a girl walking around in the room with no clothes).
(Source: Shakugan no Shana Wiki)