Anna Mochizuki is a 14-year-old idol from Kanagawa, born on May 31st. She stands 152 centimeters tall, weighs 41 kilograms, and has an AB blood type. Her hobbies center around online gaming, where she uses the alias vivid_rabbit, and she is also skilled at typing. She has a deep fondness for cute things and is right-handed. In daily life, she is quiet and withdrawn, often speaking in short, fragmented sentences that trail off, giving her a perpetually tired appearance. Despite her young age, she carries herself with a slightly mature air, and her primary interests outside of gaming are singing and her work as an idol. When she puts on her stage outfit, she deliberately shifts into an intensely energetic and passionate persona, using the catchphrase bibi~ to motivate herself and others. This vibrant personality is a role she researches and forces herself to perform, as she remains a shy girl at heart. She struggles with acting outside this energetic archetype. She rigorously practiced bass guitar to perform at the same level as the rock idol Julia during an outdoor music festival. She finds genuine joy in singing and in receiving fan mail. Academically, she finds subjects like English challenging and has been seen sleeping in class, but she shows immense focus when a task aligns with her passions, such as producing a one gigabyte text file detailing her ideal game design in a single night. She maintains a key friendship with fellow idol Yuriko Nanao, with whom she plays games online and in person. She is part of several units, including Otome Storm!, Capricorn, Pikopiko Planets, and Chrono-Lexica. In her animated appearances, she has been shown broadcasting herself playing FPS games. During the events of THE IDOLM@STER MOVIE: Kagayaki no Mukōgawa e!, she appears as one of seven trainee idols supporting an arena concert, joins a training camp, and relays Kana Yabuki’s difficult decision to quit idol activities to Haruka Amami, later participating in efforts to support Kana.