Mr. Yamaguchi is a middle-aged Japanese man who works as the president of EuroReptarLand. During Rugrats in Paris: The Movie, he was going to step down as the head of Yamaguchi Industries and had been looking for a replacement. Coco LaBouche was one of the employees under consideration, because she had made a lot of money for the company, but Yamaguchi was reluctant to name a replacement because he wanted the new president to be concerned with more than money--he wants to find a replacement who was good with children, since children are the main audience for the Reptar-franchise. When Coco lied and told him that she loved children and was engaged to a man with a child of his own, this seemed to delight him and he promised Coco that they would discuss the promotion after the wedding.