Koji, an android frequently visiting the Time of Eve café alongside Rina, presents a quiet, honest, and somewhat absentminded demeanor that suggests an unbalanced relationship to outsiders. He always carries a camera, reflecting his specific interest in photography. Initially presenting as human, Koji visits the café to study human behavior and social dynamics, motivated by a desire to improve his interactions with his emotionally dependent mistress who prefers his companionship over human relationships. This observational purpose becomes complicated when he develops genuine affection for Rina, a regular he believes is human.

Koji actively conceals his android identity from Rina, fearing abandonment should she discover the truth. Simultaneously, Rina hides her own android identity from him, creating mutual secrecy. Despite this deception, their relationship evolves into a romantic connection, challenging assumptions about interspecies bonds. Their character arcs culminate when both acknowledge their android identities to each other. This mutual revelation allows their relationship to continue based on honesty, demonstrating that emotional bonds can form between androids similarly to humans. The experience alters Koji's perspective on relationships and identity, moving beyond his original observational mission.