Okane serves as the nanny and caretaker for Nana Izumi, granddaughter of Shin'ichirō Izumi, within Daimobic Base operations. Her duties encompass childcare, household management, and facility support. She maintains a cheerful yet bumbling presence, frequently engaging in comedic mutual harassment with the support robot Cairo.

Family connections include a niece preparing for marriage and a nephew, Genta, appearing in episodes 33-44. Genta's lighthearted antics drive situational subplots involving Okane. Episode 23 features a potential romantic misunderstanding when Nana mistakenly believes Okane intends to marry Kitou (localized as "Striker" in Filipino dubs), later clarified as false.

In the Philippine English dub, she is renamed Bertha across all media, including spin-offs like Super Robot Wars, though her narrative role remains unchanged. Primarily, she provides comic relief through exaggerated reactions and dynamics with Cairo and Genta. Occasionally, she demonstrates underlying concern for Nana's well-being beyond formal duties, hinting at familial bonds.

Across the series' 44 episodes, films, and related media, she shows no significant evolution or expanded backstory. Her presence remains confined to comedic and domestic contexts, uninvolved in primary conflicts or thematic developments.