Karuizawa Kei stands poised in a refined yet approachable pose that showcases her calm confidence. The Seifuku ver. of the Coreful figure presents her trademark long dark hair, neatly styled, and her crisp school uniform rendered with careful sculpting to highlight the fabric folds and subtle creases. The uniform jacket sits snug at the waist, flaring at the hips, with a pleated skirt that flows slightly to suggest movement. Standout details include a precise badge, sailor collar, and a decorative ribbon. The paintwork emphasizes her cool, calculating gaze and the composed demeanor that defines her character in the series.

In Youkoso Jitsuryoku Shijou Shugi no Kyoushitsu e 2nd Season, Karuizawa Kei is introduced as a talented and enigmatic classmate whose outward charm masks a calculating mind. She navigates the high school environment of Tokyo's elite academy with a mix of social savvy and guarded motives. Kei uses her popularity to influence peers while quietly observing the complex power dynamics among students and staff. Her relationship with the protagonist evolves as the plot reveals her fears, ambitions, and a desire to secure a favorable position within the competitive system. Her character adds tension and strategic depth to the classroom's social chess game.