Miyu Mifune is a 26-year-old woman from Iwate Prefecture, standing 165 cm tall with auburn hair and eyes. Her physical measurements are 85-60-85 cm, and she has AB blood type. Born on February 25 under the Pisces sign, her hobbies include aromatherapy. Before her idol career, Miyu worked as an office lady. She exhibits a shy, nervous personality with difficulty in social interactions, frequently expressing self-doubt about her suitability as an idol and questioning her ability to stand before others. This stems from a history of yielding to pressure and making life decisions by "going with the flow" rather than asserting her own choices. Her background carries emotional trauma, including the death of her childhood Golden Retriever, which contributed to her melancholic demeanor. Frequent relocations in her past hindered lasting friendships. Fan interpretations speculate about possible widowhood or negative experiences with men, though these remain unconfirmed. Miyu's idol journey began on Christmas Eve when she encountered the Producer after breaking her shoe heel en route home from work. Initially hesitant due to low confidence, she accepted the opportunity after the Producer emphasized this choice was hers—marking her first significant departure from passivity. Throughout her idol career, Miyu forms meaningful bonds, acting as a motherly figure to younger idols like Nina Ichihara and Kaoru Ryuzaki by providing care and emotional support. She socializes regularly with same-age peers Kaede Takagaki, Mizuki Kawashima, and Sanae Katagiri through drinking outings. She shares a close friendship with Shin Satō and stands among the few non-child idols who genuinely believes in Nana Abe's "Usamin" persona. Miyu finds personal growth through acting and idol performances, viewing them as avenues to embody new personas. She enjoys urban night views from elevated clubs and possesses a hidden talent for golf. Her unit involvements include Yoi Otome (with Kaede Takagaki, Shin Satō, Sanae Katagiri, and Nana Abe) and Flamme martini (with Tsukasa Kiryu, Syoko Hoshi, and Hajime Fujiwara). In tie-in media like Cinderella Girls Theater skits, her nurturing personality surfaces through interactions where she assists younger idols, reinforcing her supportive role in group dynamics.