Who is Louisa in the novel, His Little Women?

Louisa is Nell's older half-sister. She is described less secure, having been fatherless for most of her life. At first she appears cynical and emotionally unattached to her father, but the truth soon becomes clear — she is in deadly competition with Nell to be his favorite daughter. Much later, when preparing for the Jack Campbell trial, she reveals her true feelings to Ronald Chow: "I was an only child. Then my father left us and had another daughter . . . I knew who he was, and it turned out I could find him in the movie magazines. So now I had a father. And I had a baby sister. Half sister. The . . . little brat had my father, and I hated her!"