The boss is the main supporting character. He might be the foreman, site manager or factory director; he represents authority. The boss gives the orders and sets the rules, and always instructs Napo directly. He is not only concerned about the safety of his staff but also about productivity. Often, he is under pressure from his superiors or his clients. Sometimes he gives orders that are contradictory or impossible to carry out. Contrary to the saying, the boss is not always right. Like Napo, he is not limited to one specific job or work environment but his personality and physical appearance remain the same in all the films.
Miss Strudel is an intense woman who represents a level of authority higher than or parallel to that of the boss. She might be the client, the works inspector or the company nurse who puts pressure on the boss and his staff. Miss Strudel is amusing through her excesses. Napo himself may be seduced by her rather special charm.
Napette may perform the same or similar duties to Napo or a different job but in the same work environment. Occasionally she makes mistakes in her job. Napette is attracted by Napo’s charm but her attempts to help him sometimes irritate or annoy Napo.
Depending on the stories, Napo may have one or two colleagues working in the same company and doing the same or similar jobs. These characters serve as a foil to Napo's exploits. For the main part, they are sensible employees who more or less follow the rules.
A frog, a dog and other animals also enter the world of Napo. These animals are likeable characters that help to develop the stories and give a cartoon touch to the adventures of our hero.
In true cartoon style, objects come to life and react to or criticise the behaviour of Napo; for example, the safety signs that speak and wave their arms in the film ‘Best Signs Story’.