Seiya Uzaki, a fourth-grade student at White Dove Academy and doctor’s son, aspires to inherit his father’s medical career while living as the protagonist’s neighbor, childhood friend, and classmate. Balancing mischief with loyalty, he delights in video games, sports, and teasing the protagonist yet remains fiercely protective. Academically average yet strategically gifted, he thrives in conflicts, crafting countermeasures through sharp tactical thinking.

Initially oblivious to the protagonist’s secret identity as a magical guardian, he later uncovers her role and inherits psychic powers from an ally, becoming integral to combating adversaries. The manga depicts him wielding an otherworldly boomerang in specialized attire once, whereas the anime accelerates his psychic development, enabling energy projections without costume changes. His powers surge during emotional extremes like anger or desperation, though overexertion leaves him weakened.

His dynamic with the protagonist shifts from playful rivalry to quiet, unreciprocated devotion. Often dismissed despite his cautious skepticism, he accurately distrusts eventual traitors within their circle. A mentor’s death spurs his transition into a steadier, more solemn role, though he retains levity via deadpan quips.

His growth diverges across media: the manga delays his combat involvement until later arcs, while the anime accelerates his integration as both a strategic advisor and emotional pillar. Evolving from impulsive backup to decisive frontline ally, he repeatedly risks himself in battles. Key contributions include aiding in major antagonist defeats and supporting the protagonist’s sacrificial choice, though his final destiny remains unresolved.