Midori, born April 17, 1990, originates from the reincarnated spirit of a raccoon who perished after consuming toxic mushrooms, leaving her with lingering toxicophobia. Discovered injured in a snare by young Gorō Mutsumi and his cousin during a countryside visit, she was nursed to health, named Midori, and reluctantly returned to the wild. Her death soon after solidified her protective bond with Gorō, whom she now serves as a guardian angel, regarding him with sibling-like devotion rather than romance.

Her innocent demeanor and steadfast loyalty drive her to shield Gorō at all costs. Initial friction with Akane, a fox-derived guardian angel, arises during shared duties and clashes at a soba restaurant, but rivalry softens into camaraderie through collaborative efforts and mutual respect. Later, Midori forges a partnership with Tamami at the same restaurant, balancing work with newfound trust. Subtle shifts in physical measurements across seasons mirror her gradual growth, though her essence—naivety, unwavering loyalty, and wariness of unfamiliar foods—persists. She enthusiastically devours soba noodles, a culinary passion unchanged by time, while navigating interpersonal challenges and evolving responsibilities.