Naoko Seishō is a traffic police officer in the Katsushika district police force, operating as an inseparable duo with her partner Komachi Ono during traffic enforcement duties. They share a contentious yet interdependent dynamic with protagonist Kankichi Ryotsu, derisively labeling him 'Gorila' or 'Troglodita' due to his unrefined appearance and occasionally destructive superhuman strength. Despite this antagonism, they acknowledge Ryotsu’s underlying competence as a police officer and periodically seek his assistance for professional or personal challenges, though he sometimes demands reciprocal favors.

Their professional responsibilities focus on traffic patrol operations, typically conducted from police vehicles. Both exhibit strong-willed personalities yet demonstrate notable shyness regarding romantic pursuits, actively seeking relationships but encountering difficulties partly attributable to their assertive dispositions. Their partnership extends beyond professional collaboration into close personal friendship, frequently coordinating actions during operations and social interactions.