Reika was adopted by Kisaragi Akiba when she was around 10 years old. She had been abused by her show business mother, and blaming herself for the abuse committed by her mother. When Kisaragi found her, they were both in need of each other. Kisaragi had lost many people close to her and was in a deep depression, whereas Reika needed a mother and Kisaragi's music helped her through her hard times. Once adopted by Kisaragi, Reika started singing and in no time she was a star like her adopted mother. When Kisaragi started her S-class and started looking for the next singing sensation, Reika found herself feeling alone without Kisaragi by her side, but came to an understanding after Shirou Sugino assured her in regards to Kisaragi's feelings.

Reika is the inspiration for Akari, Yuki, and Nozomi on their path to becoming singers themselves and the three girls respect Reika and look up to her.