Roko-chan is the affectionate name Hamtaro and the Ham-Hams use for Laura Haruna, Hamtaro's primary owner. A ten-year-old schoolgirl, Laura provides care and shelter for Hamtaro. Her Japanese given name is Hiroko Haruna, with "Roko-chan" forming a diminutive of "Laura" within the hamster community. She serves as Hamtaro's central human connection, her departures for school or activities often sparking his daily adventures. The hamsters perceive her as a gentle and responsible figure. Her relationship with Hamtaro motivates his timely returns home and his concern for her well-being. This drives narrative elements like when Hamtaro and the Ham-Hams worry during her illness and aid her recovery. Her schedule frames Hamtaro's explorations, dictating his departures and returns. She embodies the human world from the hamsters' perspective, her actions and needs occasionally influencing their activities. Her family, including her parents, provides the domestic backdrop for Hamtaro's life. Though her personal history beyond owning Hamtaro remains unexplored, her consistent presence offers stability for the hamster-centric stories. The name "Roko-chan" reflects the hamsters' linguistic custom for their human caregivers.