Ruby, a Japanese hare Jewelpet, sports white fur, pink inner ears, and ruby-red crystalline eyes. A pink cherry blossom adorns her left ear, complemented by a necklace of red cherry-shaped charms. Her Jewel Charm form centers on a heart-shaped ruby encircled by crystals, its white gold accents shifting to gold when activated. In human guise, she mirrors her floral motifs with cherry-red hair, matching eyes, and pastel pink-and-white attire.

Polite and tidy, with a deep affection for cherry blossoms, Ruby’s demeanor fluctuates across stories. Early portrayals highlight her scatterbrained mischief and accidental magical explosions—a result of her Acrylic Class spells, which fail 99% of time but sporadically amplify human luck or courage. Later arcs recast her as a resilient mentor and supportive confidante, balancing her impulsiveness with unwavering optimism.

Exiled to Earth for evading transformation into a Jewel Charm, she collaborates with diverse human partners to reclaim lost Jewelpets. Her missions span thwarting jewelry heists, competing in magic tournaments, and operating a café. Key bonds include a protective dynamic with a timid partner, a rivalry-turned-alliance over a mutual crush, and guiding a future Jewel Land ruler.

Despite advancing to Super Crystal Class through training, her magic remains erratic. She wields the Jewel Pocketbook and Jewel Stick to awaken dormant Jewelpets and joins collaborative spells requiring teamwork.

Storylines explore her navigating high school romance, mending rivalries amid external crises, and spearheading campaigns to reignite faith in magic. A unique arc pits her against parallel-universe counterparts, whose resolve inspires her growth.

Born July 29—a date symbolizing luck and courage—her design initially carried the name “Kohaku” before aligning with ruby motifs. Romantic subplots involve a human boy in earlier tales and a classmate later tied to her partner through family lineage.