Midori Kasuga works as a nurse within the hospital overseen by her stepfather. Her mother, Hinoki, married the director but died young. Midori exhibits particular tenderness while caring for a comatose patient named Hinoki. This hospital setting masks a complex exchange of identities: the silent Hinoki is actually the biological daughter of the director and the true bearer of the name "Midori Kasuga." The nurse known as Midori adopted this identity for motivations undisclosed, leaving her original name unknown.

Her physical appearance features green hair, worn either in very long twin braids or short lengths, paired with amber eyes. She typically dresses in a nurse's uniform, a nurse's cap, a beret, glasses, and sometimes a capelet. Her demeanor presents as friendly and diligent, reflecting her commitment to nursing duties despite underlying tensions.

A significant element of her experience involves enduring repeated sexual abuse by her stepfather. This trauma stays concealed until another patient, Takumi, witnesses an assault during a vision triggered by his head injury. Midori refuses to acknowledge the abuse when questioned by Takumi, indicating her entrapment within the hospital's oppressive dynamics. Her narrative also intersects with themes of torture, though specific details remain unspecified in the available material.

The character's background and experiences are intrinsically tied to the hospital environment, her stepfather's control, and the unresolved mystery surrounding her assumed identity and Hinoki's condition. The documented material does not include further narrative development or resolution.