Who is Madame de Verquin from The 120 Days of Sodom and Other Writings and what is their importance? 120_Days_of_Sodom English & Literature Madame de Verquin | The 120 Days of Sodom and Other Writings

This is the sister of Florville's adoptive father, Saint-Prat. Florville goes to live with Madame Verquin after the death of Saint-Prat's wife and is encouraged by her into an affair with Senneval. Madame de Verquin lives an indulgent life and dies happily.