The Mysterious Woman was an Evolved Human who eventually wandered to Green Roof Apartments.
The Mysterious Woman wears a blank expression on her face. She is of pale complexion with long, waist-length brown hair. She does not wear any clothes.
It is entirely unknown what this person was like prior to turning into a monster or while she was a monster. As an Evolved Human, she does not seem to display any sign of emotion, nor does she react to anything.
She first appears standing on the edge of the apartment's roof as Ihyun Jo chases some monsters. However, as Ihyun is distracted by a monster, she moves away and Ihyun loses track of her entirely, making him think he was hallucinating. She later appears before Gapsu Seo, who is looking to satisfy his primal and immoral urges. The Bat Monster, however, attacks Gapsu before he could do anything. She reappears before Gapsu again, as well as Yuri Park and Hyein Son. Gapsu is visibly afraid of her, as he remembers that her appearance coincided with the Bat Monster's attack and that the monsters aren't interested in attacking her. Yuri and Hyein are very confused, and are unnerved by her lack of reaction to anything. Hyein, losing her composure, uses a crossbow to kill the Mysterious Woman by shooting her in the forehead.
Myeong-Ja Lim and Hyuk Lee discover the corpse, wondering who in their right mind would go about their business entirely naked even during an apocalypse. Her corpse is eventually discovered by the monster horde, which further infuriates them.