Mai Takano is introduced as a university student and a research assistant to the enigmatic philosophy professor Ryuji Takayama. As a young woman drawn into the terrifying mystery of a cursed videotape, she is characterized by her deep affection and loyalty to Ryuji, which becomes the primary motivation for her actions following his sudden death. Her background establishes her as an ordinary individual whose life is irrevocably altered when she crosses paths with the supernatural curse, transforming her from a peripheral figure into a central protagonist who confronts the legacy of the psychic killer Sadako Yamamura.

Her personality is shaped by a combination of determination and vulnerability. Mai demonstrates remarkable bravery and a nurturing instinct, taking on the responsibility of protecting Yoichi, Ryuji's young son, after his parents are killed by the curse. She is resourceful, driven by a need to understand the inexplicable events surrounding her, and shows a strong maternal side in her relationship with the boy. However, she is not immune to fear; she often faints or shows visible distress when confronted with the supernatural horror, a trait that highlights her humanity and the immense psychological toll of her situation. Her perspective often shows her to be insightful, able to perceive details that others miss, even as she struggles with overwhelming dread.

Mai's primary motivation throughout her story is to uncover the truth behind Ryuji's demise and to prevent others from suffering the same fate. This quest for answers leads her to investigate the cursed tape, bringing her directly into conflict with Sadako's wrath. Her role in the story evolves from a grieving former student to a full-fledged heroine who actively seeks a way to break the curse. In the film Ring 2, she becomes the main protagonist, taking it upon herself to save Yoichi from Sadako's influence, demonstrating that her protective instincts have superseded her own survival. In stark contrast to the film continuity, her role in the novel Rasen (Spiral) is a tragic one, as she becomes an unwitting and crucial component in Sadako's biological resurrection, serving as a surrogate mother for the entity's rebirth.

Key relationships define her journey. Her connection with Ryuji Takayama is the most significant, encompassing a complex student-teacher dynamic tinged with romantic feelings. She is often referred to as his possible girlfriend, and her investigation is fueled by this deep personal bond. Another critical relationship forms with Yoichi Asakawa, Ryuji's son. As his parents become victims of the curse, Mai steps into a maternal role, devoted to protecting him from Sadako. This surrogate parent-child relationship becomes the emotional core of her arc in the second film. Her interactions with other investigators, such as the coroner Mitsuo Ando in the novel, are often fleeting and serve to advance the plot or provide the reader with new perspectives on the curse's mechanics.

Mai undergoes a significant, though varied, development depending on the continuity. In the film Ring 2, she develops a degree of immunity or resilience that allows her to survive her encounter with Sadako at the bottom of a well, saving herself and Yoichi while others perish. Her development also includes the acquisition of notable abilities; in some adaptations, such as the Ring manga, the exposure to the curse causes her to develop psychic powers, mirroring the supernatural abilities of Sadako and Yoichi. In the original novel continuity, however, her development is cut tragically short as her body is used to birth Sadako anew, a process that results in her death inside a ventilation shaft, a grim endpoint to her character arc.