He is the mayor of the town of Quiquendone. The Van Tricasse family has governed the town for generations with the same mechanical and excessively stagnant system; he himself initially adopted the principle and virtue of deciding nothing. However, when exposed to Doctor Ox's gas, that calm, dull man turns into someone else: an angry, shouting, quick-decision-making warlord. After the disaster at the gas factory, he returns to his former self.
He comes from the esteemed 'Jeannot' (Van Tricasse) family, whose ancestry dates back to the 1340s. It is a tradition to marry young wives from within the family when widowed. Like his father, he was raised learning the philosophy of letting life flow without making decisions.
Fifty years old; neither fat nor thin, neither short nor tall, neither old nor young. His complexion is neither colorful nor pale. He has a straight, sullen forehead like a yellow copper plate; broad shoes with silver buckles and a forty-year-old Dutch hat.
Doktor Ox
Initially sees him as a polite neighbor whom he finds respectable, later as an arrogant stranger who disrupts the course of things.
Niklausse
His closest advisor, yet he attacks him violently under the influence of the gas.
Brigitte van Tricasse
While they are a wife and husband who stood silently side-by-side for sixty years, they constantly bicker with each other in the final stages.