Yuito Aoi, a third-year student at Minamigaoka High School, stands 175cm tall with auburn hair and grey eyes. Raised by his mother in a fatherless household, his lifelong passion for drawing became increasingly private as he aged. Generally quiet and self-contained without shyness, he appears distant or irritable during initial encounters—especially when vulnerable—but reveals kindness and humor among close companions like the Photography & Art Club members. He remains loyal to these friends, engaging in their unconventional activities despite reservations.

His routine fractures when Hitomi Tsukishiro materializes in his room from the future. Discovering her blue earring, he dismisses rumors of a "white-haired girl" as a burglar. Upon their formal meeting, he scoffs at her claim of being a time-traveling mage, later regretting his demand for public proof of her magic. Their bond deepens through Hitomi’s unique perception: her trauma-induced monochrome vision transforms into vivid color solely when viewing Yuito’s art. This revelation flusters him, igniting a resolve to create ever more beautiful work for her.

Yuito battles unacknowledged emotions, particularly his burgeoning affection for Hitomi, responding defensively when vulnerable. After snapping at her accidental interruption of his drawing, he apologizes. His emotional walls gradually lower through shared time with her and the club. While working part-time at a café owned by junior member Chigusa Fukasawa’s father, a pivotal moment occurs: Hitomi magically summons a yellow fish from his childhood sketches to cure his artist’s block. The image triggers a painful memory, provoking his anger. He later pursues her to apologize, pledging a new drawing to lift her spirits.

As Hitomi’s inevitable return to her timeline looms, Yuito stays silent upon learning she must leave. During the farewell ritual, he hesitates to voice his feelings. When the magic destabilizes, he leaps into the chaos to reach her. Stranded together in a colorless void, he confesses his love and gratitude, crediting her for shattering his emotional and creative barriers—a catharsis that permanently restores Hitomi’s color vision.

After her departure, Yuito channels his experiences into a series of color picture books. These volumes reach Hitomi as a child in her timeline, becoming cherished treasures and her only source of color in a monochrome youth. Decades later, an elderly Hitomi visits his grave with gratitude. His evolution—from an emotionally guarded, stifled artist to one who openly expresses feeling through transcendent art—leaves an enduring legacy across time.