Birth Date: November 7, 1997
Blood Type: O
Height: 159 cm
Weight: 46 kg
Sizes: B 75 cm / W 57 cm / H 83 cm

A first-year high school girl unrivaled in her talent for singing and dancing. Originally the first Center Girl for the I-1 Club, various circumstances caused her to quit and leave for Sendai, where she was eventually found by Matsuda and unsuccessfully scouted for the Wake Up Girls! project. She eventually joins the idol group, realizing that she loved singing and dancing to the point where she couldn't give them up no matter what and that she wanted to try to find happiness, at least for herself.

It was revealed that her quitting the I-1 Club was due to her standing for her ideals against I-1 Club's strict environment. Standing up against I-1 Club's President for firing one of her friends despite her desire to continue working for I-1 Club, he cornered her into an ultimatum, claiming that if her single sold less copies than the other single that was being released simultaneously featuring a new Center Girl, she would be fired. With her singles selling less, she was forced out of I-1 Club, followed by a flurry of presumably baseless scandals (presumably crafted solely to permanently damage Mayu's reputation) and her parents divorcing, resulting in Mayu living with her Mother in Sendai. Scarred by her experiences in the Entertainment Industry, she idled in Sendai, unsure as to how she should move on with her life despite still loving the idea of being an Idol, singing, and dancing.