Makoto Washio is a human character introduced in the 2007 anime adaptation. A senior college student studying science and engineering, he first encounters Rokuro-Kubi during her part-time work at a school store alongside Neko-Musume, initially knowing her by the human alias "Rokuko."

A pivotal moment occurs when Makoto sustains a leg injury during a confrontation with the yōkai Odoro-Odoro. In this incident, Rokuro-Kubi stretches her neck to call for help, revealing her true yōkai nature. Instead of reacting with fear or rejection, Makoto finds himself unable to think of any other woman afterward. This acceptance quickly leads to the two beginning a romantic relationship.