Washio functions as Reimi Jahana's personal secretary within the Jahana Group, the organization administering the Variable Geo tournaments. His professional duties encompass managing corporate affairs and assisting Reimi with her executive responsibilities.

Beyond their formal association, Washio and Reimi maintain a private romantic relationship. An intimate encounter between them is disrupted by Chiho Masuda's infiltration of the Jahana headquarters, an intrusion that ignites a confrontation between Reimi and Chiho due to Reimi's traumatic recollections of her mother's severe training.

Washio engages in corporate strategy sessions and internal probes, specifically targeting the covert operations of the "independent division" previously commanded by Reimi's mother, Miranda Jahana. He supports Reimi's investigations into the division's unethical experiments and hidden agendas.

Amid the climactic destruction of the Jahana Group's research facility, Washio extracts Reimi from confinement, guaranteeing her safety as the complex collapses.