Keiko Furukawa works as a beach patrol police officer, characterized by long black hair typically in a ponytail, purple eyes, and occasional swimsuit use during operations. Her background includes serving as high school Student Council President, where she encountered Ruka Shirosugi and Mari—later recognizing them in their roles as a beach nurse and kindergarten assistant respectively.

She displays marked clumsiness inconsistent with law enforcement duties. Key incidents include accidentally handcuffing herself during a burglary apprehension—resulting in being taken hostage—and attempting an arrest while wearing only a bikini without official identification. These shortcomings led to reassignment to lighter responsibilities like traffic safety education.

Initial interactions with Ika Musume involved suspicion over Ika's appearance and ink-related incidents, nearly leading to arrest. Joint experiences addressing serious matters such as the "Three Stooges" incidents fostered mutual respect. This evolved into a cooperative dynamic where Ika views her as a legitimate authority figure participating in children's recreational activities.

Eiko Aizawa expresses concern over Keiko's professional conduct, acknowledging her role in resolving Lemon Beach House issues but criticizing amateurish methods and inappropriate hot-weather patrol attire. A recurring trait is susceptibility to distractions, exemplified by forgetting map directions when interrupted by children reciting video game cheat codes.

Her debut occurs in OVA 3 and manga Chapter 275. Physical characteristics include a birthmark or mole noted in character registries.