Older sister of Ermes Costello. She is a woman of average height with blonde hair and blue eyes. After their mother died, Gloria acted as a mother figure toward Ermes. She also took over the family restaurant from their father, a Mexican immigrant, when she was 20 years old. Gloria Costello was described as a lively and strong-willed individual. She also had a serious side, and was more of a mother figure than a sister to Ermes. Gloria constantly nagged Ermes to have her help at the restaurant. Confronted with a brutal murder on her steps, she initially chose to let the crime happen and never mention it, as she was attached to the restaurant, but Sports Maxx witnessing Ermes going away forced her to call the police to protect her sister.