Gloria, whose full name is Gloria Knopp, is the wealthiest woman in the city of Catalina and serves as a secondary antagonist within the narrative. She is the owner of the building where Gina, her family, and Topo Gigio reside, making her their landlady. Her character is defined by her greed, cynicism, and generally surly demeanor. She never misses an opportunity to tease and provoke her tenants, frequently threatening to evict them if they fail to pay the rent on time. At the beginning of the story, she had plans to demolish the apartment building, but she was forced to abandon this intention due to the intervention of Topo Gigio.

Her harsh and misanthropic behavior is largely rooted in a past unhappy love affair. In her youth, she was in love with the pastor of the local church, who ultimately decided to break off their relationship in order to take his religious vows. This painful romantic rejection is the key to understanding her bitter personality and her generally antagonistic treatment of others.

Within the story, Gloria is not only the landlady but also the mistress of a cat named Megalo. She frequently punishes Megalo for his various defaults and the troubles he causes, though these issues are often managed by her subordinates or by Topo Gigio. Her interactions with Megalo form a notable relationship, though it is characterized by her continual frustration with the cat's behavior. Her role in the story is primarily that of an obstacle for the main characters, a source of tension and conflict regarding their living situation, and a figure whose past sorrows reveal a hidden dimension to her villainy. Her notable abilities are not centered on physical power or special skills, but rather on her social and economic influence as the richest woman in Catalina, which she wields to exert control and pressure over those around her.