Makeru Yadano is a fiercely competitive student at Itan Private High School who declares herself the rival of Shouko Komi. Her pastel pink hair falls in low twin tails tied at the back of her shoulders, with bangs cut above her eyebrows, and she consistently wears a beaded bracelet. During her first year, she measures 155.8 cm tall and weighs 53.8 kg, though these figures fluctuate slightly. She occasionally uses glasses for her 0.7 vision acuity. Yadano's name derives from the phrase "makeru yada no" (負けるやだの), meaning "I hate losing"—a core trait driving her relentless challenges against Komi in academics, sports, and school events like fitness tests, sports festivals, and cultural festivals. She consistently falls short, such as in grip strength (18 kg vs. Komi's 24 kg), flexibility (45 cm vs. 52 cm), and the 50-meter dash. To salvage pride, she theatrically declares artificial "ties," punctuated by a comical angry expression that becomes a recurring visual motif. Her rivalry remains one-sided for most of their first year, as Komi remains oblivious to Yadano's fixation. Yadano misinterprets Komi's social anxiety—like freezing during interactions—as deliberate arrogance, intensifying her resolve. Despite simmering resentment over Komi's superiority, Yadano never cheats or vents directly at her, instead funneling frustration into rigorous self-improvement. This stubborn perseverance inadvertently attracts a fan club of masochistic male students, including Chiarai Shigeo, who admire her tenacity. A pivotal shift occurs during the third-year sports festival relay. After narrowly losing to Komi again, Yadano breaks down, revealing her exaggerated reactions were partly performative—a shield against genuine disappointment and pity. Komi finally recognizes her resilience, acknowledging Yadano as a "formidable rival," transforming their dynamic into mutual respect. Beyond school, Yadano exhibits similar competitiveness with her family, particularly her older brother Katsuki. She harbors hidden talents like facial tricks and achieves above-average grades in science and social studies despite overall mediocre academics. Yadano becomes Komi's fourth officially listed friend by signing her "friend book" early in their acquaintance. Her "Makeru-chan Fan Club" remains active throughout high school, celebrating her persistence rather than victories.