Who is Kristina Nilsson from The Last Letter Home and what is their importance?

Kristina Nilsson is one of the main characters, as well as Karl Oskar Nilsson's wife and the mother of their children. She immigrates to Minnesota with her husband, though she does not really want to leave the country of her birth. When the Civil War breaks out, Kristina objects to Karl's participation because she worries about his eternal soul. Karl's lame leg, however, causes the doctors to reject him for service. Kristina has the utmost faith in God, and she prays daily to live longer for her husband and children. When she gets sick, bleeding between her legs, Ulrika convinces her to go to the doctor, who warns her next pregnancy will kill her, but this causes Kristina to feel like a useless woman, as she can no longer be a wife to her beloved husband.