Kengo’s sister. She is 15, two years younger than Kengo. She is half Russian, as her mother Veronica was an exchange student from Russia. Her brother’s features take after their Japanese father much more than hers do, and because of this Olga has developed something of an inferiority complex. This manifests itself as an obsession with classical Japanese fashions, and Olga's blonde hair is usually adorned with traditional Japanese hair beads.

She is concerned about Kengo’s suspicious activities of late.