Mejiro Dober, a horse girl of the esteemed Mejiro lineage, maintains a cool, reserved exterior often marked by visible tension in social settings, especially around men. This demeanor traces back to her sheltered upbringing within the Mejiro household, where even frequent visitors couldn't ease her discomfort with unfamiliar interactions and attention. Beneath this initial coldness, she reveals a less rigid personality to those who consistently engage with her, demonstrating a noted desire for personal change. Physically, she possesses jet black or dark purple hair cascading neatly past her back, usually secured by a teal hair clip on her left side. Her pink or light lilac eyes complement her features, while distinctive teal ribbons adorn her left ear, signifying her mare lineage. She stands 157 cm tall with measurements of 83-57-81 and a shoe size of 22 cm. Her standard racing attire includes a white frilled blouse, a teal ribbon collar, layered teal skirts with gold accents and white frills, white teal-striped socks, and short-heeled boots. Beyond racing, she exhibits proficiency in piano and childcare, skills comparable to a kindergarten teacher. She holds extensive knowledge of tea brands and prefers hair care products suited to her hair type over brand names. A personal secret involves a self-drawn shoujo manga notebook hidden in her drawer. She prioritizes making direct eye contact when speaking with young children and reviews race strategies by locking eyes with her trainer before competitions. Thunderstorms notably unsettle her. Her background mirrors her namesake racehorse's career. Debuting on July 13, 1996, she won her maiden race at Niigata Racecourse. After a fifth-place finish in the Niigata Sansai Stakes, she achieved a three-race winning streak, capturing the Hanshin 3-Year-Old Fillies Stakes. Her most triumphant year came in 1997, securing five mare-limited Grade 1 titles under jockey Yutaka Yoshida. These victories included the Japanese Oaks and two consecutive Queen Elizabeth II Commemorative Cups, completing the "Double Tiara". This success fulfilled the unrealized Classic race aspirations of her sire, Mejiro Ryan. Her competitive record showed dominance in female-only races, correlating to her character's difficulty with men and performance variations based on trainer gender in adaptations. Her name originates from the Doberman breed, following Mejiro Farm's 1994 foal naming convention using dog breeds. After racing, she transitioned to breeding at Lake Villa Farm following Mejiro Farm's 2011 dissolution, continuing there until 2016. She now serves as a lead horse for foals alongside her son, Ho O Dream, in northern Japan. Her offspring include notable runners such as Ho O Ixelles (2021 Flower Cup winner) and Break Boy (purchased by CyberAgent CEO Susumu Fujita). Her daughter, Mejiro Audley, is recognized within the franchise for having four ancestors depicted as horse girls. She shares living quarters with Taiki Shuttle. She interacts with Mejiro Bright without using honorifics, reflecting their shared lineage through Mejiro Ryan, though they are not considered siblings in equine terminology due to different dams. Her father expresses regret over no longer using her childhood nickname, "Ber-chan".