Ignazia is Dominick's grandmother. When Domenico first sees her, she is wearing a "woolen coat as red as blood" (37.45), the red coat being traditional literary shorthand for OMG DROOL—a.k.a. Domenico has the hots for her. He pays her guardians to get her hand in marriage because he's so in lust with her, and he ends up with her alleged cousin Prosperine in the bargain.
Both Ignazia and Prosperine hate Domenico, but Ignazia is more passive aggressive about it. Prosperine is aggressive-aggressive, and she and Domenico constantly argue. He always calls Prosperine an old monkey because she reminds him of the old monkey his brother used to own. And you know what? If we were always called old monkeys, we might just be aggressive-aggressive, too.
When Ignazia gives birth to one dark-haired boy and a red-haired girl, Domenico thinks she has two different babies from two different fathers (call Weekly World News). Actually, this is possible, especially when you consider Domenico's belief that Ignazia slept with her red-haired boyfriend before marrying Domenico, despite insisting she was a virgin.
This red-headed child pushes Domenico and his wife apart, not that they were that close to begin with, and the relationship between Domenico and these two women gets stranger when Prosperine tells her story.
According to her, she and Ignazia, who may have been named Violetta, grew up in a rural Italian village. They were friends until Violetta married an artist named Gallante Selvi. When Prosperine, who is working for a witch named Ciccolina, finds out that Selvi sexually abuses Violetta, the two women team up and kill the artist, change their names, and flee the country.
Yikes. Needless to say, Domenico is afraid they'll poison him, too, until the priest convinces him to forgive them. He tries, but then he catches Prosperine and Ignazia in bed together. He gets Prosperine committed to a mental health clinic, and Ignazia kills herself.
Many years later, present-day Dominick finds Prosperine in the retirement home where Ray lives. Because of a story Prosperine told, in which Ciccolina the witch split a live rabbit into two live rabbits, Dominick goes to Prosperine and pretends to stick two rabbits back together and asks her to forgive him, although he's probably really asking for his grandfather (Dominick looks just like him). We're not sure if this is supposed to bring peace to Dominick, his dead grandfather, the old woman, or what, and since she's too old to answer, we'll never know.