Maria serves as the housemaid for the Vega family in California. She presents a masculine and boisterous personality, fearlessly scolding members of the household. Beneath this stern exterior, she harbors deep affection for the children in her care, particularly Diego and Bernard, treating them fondly and acting as a maternal figure.

Her responsibilities extend to protecting the Vega family's interests. Demonstrating loyalty and courage, she physically intervened to defend Sergeant Pedro Gonzales, striking Lieutenant Gabriel with a large stick when he resisted arrest for treason. This act highlights her direct confrontation of threats.

Maria is entrusted with Diego de la Vega's secret identity as Zorro, making her one of the few aware of his dual life. Her position as a trusted confidante is vital to maintaining the secrecy required for Zorro's activities.

Her interactions with Bernard include discipline, such as ordering him to remove the troublesome bulldog Figaro. This directive arises from her duty to uphold household order, not malice.