Pierre comes from a long line of trained cooking judges. He can tell when a dish has been carefully crafted and when a dish has just been made out of randomly combined ingredients. Pierre's goal is to taste as many different types of foods as possible.
The purple-clad chef in this version of Harvest Moon can't be married. The only time you'll have any interaction with Pierre is during the cooking festivals. Pierre will have white friendship flowers on his conversation dialog box but you can't give him any gifts or increase your friendship with him.
Watching Pierre during the festival will give you a general idea if your team is going to win the contest. While he is tasting each town's three entries, you will see a emotion bubble appear above his head; a scribble (for bad dishes), some dots (... for okay dishes), a music note (for good dishes), or a heart (for very tasty dishes). If the other town's team gets more hearts or music notes than your team, it is a pretty safe guess that you're not going to be the festival winner.