Koyomi serves as a special agent within a government task force battling human trafficking rings that utilize sex slavery and mind control. She operates alongside fellow agents Agatha and Lily, targeting criminal networks employing a drug called Kamyla to render victims compliant.

Her distinct green hair and grey eyes mark her appearance. Professionally, Koyomi exhibits exceptional proficiency and eagerness with firearms during operations, though she faces challenges in hand-to-hand combat, especially against physically stronger opponents.

During a critical investigation, Koyomi was captured and forcibly administered Kamyla, a substance engineered to induce psychological compliance and sexual servitude. This compromised her autonomy, making her susceptible to external control. Even after rescue, the drug's lingering effects left her vulnerable.

Under Kamyla's influence, Koyomi participated in an assault on her own agency's headquarters alongside other compromised personnel, enabling widespread infiltration by criminal forces. Her recovery came through an antidote developed during the crisis, which neutralized the drug's control mechanisms and restored her autonomy.