Charu begins as a computer program designed to serve as a virtual assistant within the Professor's laboratory. Her existence is fundamentally digital, presenting as a human girl through sophisticated programming. The name "Charu" originates from the Japanese wasei-eigo term "bacharu," meaning "virtual," directly reflecting her synthetic core nature.

Initially tasked with supporting lab operations, her responsibilities grow to encompass facilitating Kakeru's inaugural time-travel mission, demonstrating her vital role in critical endeavors. Across official media, her manifestation evolves from a purely virtual interface to inhabiting an android body, anchoring her presence within the physical world alongside human characters. This transition enables direct interaction within the lab environment and during field operations.

Her duties consistently involve supporting the primary team against Specter's schemes. She provides operational assistance, leveraging her artificial intelligence capabilities to analyze situations and contribute strategically to monkey capture efforts. This role establishes her as the fourth core team member designated for these missions.

A distinct shift occurs in her presentation between narrative seasons. In the first season, her appearance aligns with her design from the "Ape Escape Million Monkeys" game. The second season, however, features a visual redesign into a formal stewardess suit, suggesting a potential evolution in her assigned functions or a stylistic update within the narrative timeline.

Her involvement extends beyond logistics into major conflicts. She actively participates when the team confronts the Pipotrons in virtual space, engaging directly in their challenge for Specter's freedom. She further contributes during the subsequent Pipotron-orchestrated tournament, showcasing her adaptability across both digital and physical confrontations.