From the Super Mario Wiki
Mayor Dour is the mayor of Twilight Town in Paper Mario: The Thousand-Year Door. It's easy to tell him apart from other Twilight Towners because of his large mustache and eyebrows. The word "dour" is a synonym for "gloomy", which is an appropriate description of Mayor Dour and his town. In keeping with the ragdoll-esque appearance of the Twilight Towners, patches of fluff and loose threads can be seen on his head, hinting at old age.
He helps Mario during his visit to Twilight Town by explaining the pig problem. Mario needs his permission to pass the gate into the Twilight Trail to Creepy Steeple. Ironically, Mayor Dour turns into a pig right before Mario can visit him to ask him about it, but fortunately for Mario, the guard blocking the Twilight Trail turns into a pig as well, and the hero can thus continue on his way.
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