Akane serves as a guardian angel to Gorō Mutsumi, reincarnated from his deceased childhood pet fox. Her past life began when young Gorō and a female friend discovered an injured fox in the countryside. Gorō named the fox "Akane" after the autumn moon. Unable to keep pets himself due to parental restrictions, he entrusted her to his friend's care. During Gorō's absence, Akane escaped her enclosure when her biological parents arrived, hungry. Farm dogs attacked Akane's family during the ensuing chaos. While her parents tried to protect her, Akane was cornered and killed by a hunter's gunshot.

As a guardian angel, Akane retains physical traits echoing her fox origins, notably a hairstyle resembling fox ears and a tail. She is quiet and reserved, often perceived as aloof, though she possesses underlying warmth and forms a particularly close bond with the angel Midori. Her demeanor reflects maturity beyond her apparent age. A defining trait is her intense, visceral fear of dogs, extending even to the angel Nana, rooted in the trauma of her violent death during the hunting attack.

Her assigned color motif is orange, aligning with her name's association with the madder plant or dusk. While possessing standard guardian angel abilities to protect Gorō, no unique supernatural powers tied to her fox heritage are detailed. Her character development centers on navigating relationships within the guardian angel group and confronting the lingering psychological effects of her past life trauma.