To protect her friends who are risking their lives for a seaside sojourn, Mary provides them with medical assistance with her makeshift clinic. A Nikke who works as a doctor in the medical squad Seraphim alongside Pepper. Mary is known as the "White Angel" for her gentle demeanor, but for those patients who misbehave, she's feared as the "Black Devil", brandishing a shiny metallic syringe full of sedative.