Kanna Asou is one of the four central characters in Run=Dim. She is a fourteen-year-old Japanese pilot serving as a member of JESAS, a military organization formed by the Japanese government to help restore the nation following catastrophic flooding caused by polar ice cap melting. Within the organization, she operates as a pilot of a RUN=DIM mobile weapon, a type of robotic armament controlled by individuals possessing a quality known as Augmented Intuition. She works alongside her co-pilot and teammate, Kazuto Moriguchi.

In terms of personality, Kanna is characterized as a cheerful and smiling young girl with an unshakable and steadfast nature. Her positive disposition remains a core trait even as she finds herself at the center of a conflict that will determine the planet's future. Her cheerful outlook is notably grounded in her deep emotional connection to her partner, as she is in love with her co-pilot, Kazuto.

Kanna's role in the narrative is primarily defined by her position within JESAS. She is one of four young pilots whose actions, decisions, and relationships form the core of the story. Alongside her JESAS teammate Kazuto Moriguchi and the opposing pilots Doota Kang and Mirai Yu of the environmental protection agency known as the Green Frontier, Kanna is caught between the competing ideologies of military-controlled space nuclear disposal and environmental preservation. The story explores how the bonds of love, friendship, and a sense of duty that arise between these four individuals ultimately influence the destiny of the Earth.

Her most significant relationship is with Kazuto Moriguchi, a fellow fourteen-year-old Japanese JESAS pilot who shares her love for music and car racing. Her feelings for him are a primary motivating factor in her actions. The specifics of her personal background before joining JESAS, her detailed growth arc throughout the series, and a full accounting of her abilities beyond piloting are not elaborated on in available information.