Mari Kunou is an Order User and a member of the Group of Ten, serving as the Ninth Hand within the Dazaifu Government Organization. She is a mature woman with orange hair and eyes, typically seen wearing a crimson suit and glasses. Her demeanor is strict and businesslike, reflecting her role as an acting coordinator and professional tactician. She often takes charge of planning and communication, acting as the spokesperson for the group's leader, Eiji Hoshimiya, and outlining strategic operations such as declarations of war.

Her motivation stems from a personal desire born from her own physical limitation: she wished to see light due to her poor eyesight. This wish granted her the Order known as Curve Ray, an ability that allows her to manipulate light. With this power, she can generate lasers, create optical camouflage to conceal herself or others, and view distant objects as if through a telescope, making her a versatile support and combat asset in the field.

Mari Kunou's role in the story is that of a loyal and capable subordinate within the Group of Ten. She coordinates missions, relays orders, and uses her tactical mind to advance the organization's goals. Her relationship with Eiji is one of professional deference, and she interacts with other members of the group as a senior figure. While her backstory beyond her wish is not extensively explored, her strict professionalism and dedication to her duties define her personality throughout the series. Her development remains largely consistent, with her abilities and strategic importance being the primary focus of her contribution to the narrative.