Shirley is Kiritsugu's childhood friend and the assistant of Noritaka (Kiritsugu's father).
Shirley is created by Gen Urobuchi and designed by Takashi Takeuchi as one of the minor characters for the Fate Zero anime series. She originally appears in the visual novel Fate Zero, and makes her first anime debut in Fate Zero episode 18, Distant Memories.
Her Japanese voice actor is Ayahi Takagaki. She has no information regarding any inspiration used to create her.