Cubey, a magenta-haired succubus demon with piercing gold eyes, mirrors another character’s appearance so precisely that she trains to become their double. Driven by curiosity about their fame, she adopts their traits to infiltrate schemes, using her mimicry to aid escapes or create distractions. Her deceptive role thrives on exploiting the pair’s near-identical looks.

Physically affectionate interactions define her relationships: clasping hands, resting against the character mid-sleep, or embracing in bedrooms bathed in pink, glittering ambiance. These moments blend mischief and warmth, underscoring her playful rapport. Her dynamic shifts temporarily with Incyun, an older brother figure whose stern resemblance sparks self-reproach over her perceived idleness—until his relaxed demeanor dissolves her guilt.

Adaptations reshaped her name from "Succyun" (Japanese) to "Bussy" (manga), then "Cubey" (anime), sidestepping linguistic pitfalls. While her origins and long-term ambitions remain unexplored, she consistently serves as a comedic accomplice, enabling the protagonist’s chaotic endeavors through situational wit and strategic impersonation.