Mina Okura is Ryosuke Kaga's childhood friend, their bond stretching back to early youth where he often acted as her protector. This established dynamic cultivated strong feelings for him that endure into adolescence. She exhibits persistent tolerance for Ryosuke's overtly lecherous behavior and remains untroubled upon learning Lisara Restall is a Grim Reaper, permitting their energy-sharing arrangement to continue.

Physically, Mina possesses shoulder-length brown hair and purple eyes frequently obscured by glasses. She has a notably large bust size, measured at 92 centimeters and described variably as an F-cup or G-cup, a trait that developed early in her youth. Her glasses, reserved demeanor, and figure combine to create an impression of innocent attractiveness.

Her personality is characterized by shyness, a soft-spoken nature, and social awkwardness. She is demure, patient, reserved, and naive in interactions. Despite full awareness of Ryosuke's preoccupations, she harbors no resentment and maintains unwavering support for him.

Within the story, Mina forms a contract with the Grim Reaper Quele Sellier specifically to aid Ryosuke. This contract channels Mina's emotional energy, particularly when discussing Ryosuke, to empower Quele. Quele wields a gladius named Carnun Solace, channeling ice-based elemental attacks in combat. Mina's role spans the anime, manga, and light novel adaptations. Key narrative moments include her acceptance of the supernatural circumstances involving Ryosuke and Lisara, her steadfast support during conflicts, and her indirect participation in battles by providing energy to Quele.

Mina herself possesses no unique combat abilities or powers outside the energy-sharing mechanism with Quele. Her significance lies primarily in her enduring emotional connection to Ryosuke and her supportive partnership with Quele.