Louise’s rivalry with her twin sister is one of the central conflicts and themes of the novel. Louise, who identifies herself with the biblical Esau, another older twin who lives in his sibling’s shadow, believes that her fate is to be neglected and abandoned in favor of her sister, even as she also fights this situation. Much of this struggle is internal, meaning that the emotions it stirs up in Louise are largely repressed and come out only in violent confrontations. Moreover, Caroline seems blithely unaware of the depths of Louise’s resentment and is often surprised by her actions. Even their parents do not register Louise’s sense of rivalry.

Still, the painful consequences of this sibling rivalry are apparent when Louise explains that Caroline is the only one with the power “to slice [her] flesh clear through to the bone” (73) with a single glance or word. This highlights the reality of conflict between siblings. Though they are not close, Caroline is still the closest person in Louise’s life; whether they like it or not, their lives unfold in uncomfortably close proximity,

Louise compares herself to Caroline and finds herself lacking. Where Caroline is pretty and blonde, Louise is plain and dark.