The Eiyuu Senki Billy the Kid Swimsuit ver. figure captures a playful yet fierce charm in a dynamic swimsuit outfit. She stands in a relaxed, confident pose, one hand on her hip and the other casually brushing her wind-swept hair, with long twin tails flowing behind her. The swimsuit is a stylized two-piece in navy and white with gold trim, featuring crisp lines like a sailor-inspired design and small emblem badges at the hips. The sculpt highlights the character's athletic build and leg lines, with subtle shading on the skin to replicate sunlit tones. Her hair is sculpted with individual strands and soft curls that catch the light, and tiny water droplets on the suit give a splashy, beach-ready feel. The base is a beach-themed platform with wave motifs and tiny seashell props. The figure uses PVC for the main body with ABS joints, and the paintwork employs vivid yet balanced colors to evoke a warm, seaside atmosphere while maintaining the character's iconic confident expression. Overall, the pose conveys speed, agility, and readiness, matching Billy's clever, daring persona within the Eiyuu Senki universe.

In the Eiyuu Senki universe, Billy the Kid is reimagined as a bold, roguish heroine who joins a grand alliance of famous figures from history and legend. She is depicted as a quick-witted tactician with a fearless streak, relying on cunning and timing rather than sheer power. In the storyline, Billy navigates shifting alliances, outsmarts stronger foes, and embodies a sense of independence and freedom. Against a backdrop of cosmic wars and godly machinations, she brings a Western swagger to the battlefield while remaining loyal to her comrades and to the cause they fight for. The swimsuit variant emphasizes a carefree, sunlit side of her personality, yet her signature confidence and readiness to act remain evident. Through her arc, themes of daring, resilience, and camaraderie emerge as she faces rival gangs, uncovers hidden loyalties, and travels across fantastical lands. This character history adds depth to the figure, turning a pose on a platform into the story of a daring heroine who embraces danger with a smile.