Leonard's blind daughter who becomes the motivation for his horrific crimes. After multiple failed eye transplants, she regains sight following her father's murder of his assistant. Horrified by the basement of victims, she feigns blindness to lower her father's guard, then frees the captives and watches as one of them blinds Leonard.
Nancy is present within the household being investigated, but the plot does not show a direct conversation between them.
Detective Simon investigates the death of an eyeless woman and visits the household for a professional opinion about the body.
Katherine's professional involvement ultimately becomes the physical means of Nancy's restored vision.
Katherine assists the eye-transplant experiments, and after her death her eyes are harvested and transplanted into Nancy.
Their engagement becomes part of the doctor's scheme to restore Nancy's sight.
The plot explicitly identifies Dr. Dan Bryan as Nancy's fiancé before he is drugged and used as an eye donor.
Explore the full interactive character relationship map of Mansion of the Doomed