Carmen

Carmen is a cook rival of Zeff (Sanji's mentor), and, eventually, of Sanji as well. She challenged Sanji to participate against her in a cooking contest. Sanji, at first, wasn't interested. But a humongous fish called a Blue Fin Elephant Tuna was offered as the first prize, and Sanji was convinced to enter. It came down to him and Carmen in the end and, before the victor was announced, Carmen conceded defeat, knowing she had lost, but bore no grudge against Sanji. She is followed around by her two short assistants, Leo and Jose.