Natsuko Masaki appears exclusively within the original "Doukyuusei" visual narrative. A 21-year-old design school student, she balances her studies with part-time work at a clothing boutique. Her personality is characterized by a chill and friendly disposition. Her storyline involves a complicated relationship dynamic connecting her to the protagonist's friend Kazuya and Kazuya's girlfriend Kurumi. Concrete details regarding her background, character development, or appearances in the anime "Dōkyūsei: Climax," related OVAs, movies, or spin-offs are absent from the documented sources. Focus in descriptions of "Dōkyūsei: Climax" centers on characters such as Miho, Misa, Kurumi, and Satomi, without reference to Natsuko Masaki.