Karashina possesses an androgynous appearance marked by long purple hair and dark blue eyes. His attire features a skintight black suit with red lining, a yellow scarf displaying a red floral pattern, and a purple skirt paired with red-lined black Samurai tassets. Completing his ensemble are purple leggings, black shoes with yellow lining, and a red forehead band inscribed with "Jyou" — a symbol of fealty to his master.

He leads and speaks for the Shadow Sanjushi, a trio of ninja brawlers, specializing in Darkus attribute battles with his primary Bakugan partner, Borg Mahisas. In combat, Karashina deploys two signature techniques:
- **Poisonous Insult (Dokubari no Jutsu)**: Disrupts foes by exposing embarrassing secrets via a minuscule autocue on his index finger, targeting Tatsuma (incontinence), Hono Moetaro (romantic failures), and Harubaru (short-term memory), though Harubaru resists its effect.
- **Soothing Waterfall (Takitsubo no Jutsu)**: Demoralizes adversaries by recounting Master Jyou’s tragic backstory, supplemented by crudely drawn sketches in the anime, yet Harubaru remains immune.

Driven by vengeance against Master Shimo for Master Jyou, he debuted alongside comrades Tohga and Jinza in silhouette. He later intervened to halt Tohga’s futile battle against Harubaru. Official records document his tag-team defeat alongside the Shadow Sanjushi against Raichi, Harubaru, and Tatsuma across episodes 10–14. The name "Karashina" translates to "mustard" in Japanese.