Mejiro Dober is a racehorse girl from the prestigious Mejiro household in Umamusume: Pretty Derby. Raised under a chief trainer who recently passed away, she struggles with self-doubt, feeling weak and unable to perform in crowded races due to anxiety that makes her heart race and body weaken. Despite her cool and reticent demeanor, she remains tense around others, particularly men. Determined to become a strong Uma Musume, she pushes herself to train alone but finds support from her new trainer, who assures her she is not alone. Specializing as a Late Surger with A-rank aptitude, she excels in medium-distance races, activating her unique skill from midpack positions. Her story involves overcoming personal hardships to win G1 races and achieve victory.