Reika Aiba (born 1968) was a Japanese hostess who lived in Kabukicho, Tokyo during the 1980s. She was raised by a single mother who split from her father, an unsuccessful businessman, when she was five, and she came to work as a hostess with the goal of eventually finding her own place. In January 1989, one of her customers, Kazuma Kiryu, asked her about her past, and, after hearing about her backstory, Kiryu decided that Reika must be the daughter of Fujio Misumi, who had sent him to see if Reika was his estranged daughter Natsumi under an assumed name. Kiryu convinced Reika to meet the man he believed was her father, and they had a heartfelt reunion, as their stories lined up, and Reika slightly resembled Natsumi. However, when Misumi called Reika "Natsumi", she grew confused; when Misumi asked her if she was his daughter Natsumi, using the stage name "Reika", Reika said that she kept her real name, as she did not want to put up a front. The two proceeded to bond over drinks and fruit back at the cabaret club, where Misumi decided to become her "sugar daddy", convincing an enamored Reika to call him "Daddy" and become his lover (to Kiryu's dismay).