Mother Mairest aka Marilyn Fairest is the mother of Benjamin Fairest and the wife of Father Fairest. 

Mother Mairest seems to be a kind parent who is worried over her child's safety, while also being somewhat dramatic, possible because of her occupation as an actress. This is false, as she is an abusive authority figure who does not take the word no for an answer. While her husband is able to keep some form of composure when he's upset, Mother Mairest completely lashes out and resorts to screaming whenever she is angered. She is a hypocrite, as she tells Boyfriend that Pico was a bad influence to him and that he wanted to hurt him for his own gain, which is the other way around as she and her husband have been doing that to him. Like her husband Frank Fairest, Mother Mairest is homophobic as she dehumanizes Pico by calling him a "Pest" and a "vermin".