Appearing as a secondary character in "The Haunted Mansion" segment, Nanako exhibits a Nightmare Fetishist personality. She actively seeks horror experiences driven by her enthusiasm for scary movies and fascination with the supernatural. Her decision to investigate a sinister local mansion occurs spontaneously due to its creepy appearance, and she persuades her friend Miko to join. A contrived coincidence unfolds when two other school friends, Riko and Riko's Friend, arrive simultaneously, prompting Nanako to lead the group inside.

During exploration, Nanako displays a playful side by startling the easily frightened Miko with a flat scare. The narrative culminates in an Everybody Dies Ending where Nanako and her friends fall victim to the mansion's ghost. She experiences explicit body horror as seams appear on her joints before suffering dismemberment while conscious, confirming her death within the story.