The Grand Duke is one of the people of Auradon. He appeared in the book Return to the Isle of the Lost: A Descendants Novel and in the Royal Cotillion scene of Descendants 2. He works for Cinderella and King Charming.
Return to the Isle of the Lost
At the end of Descendants 2, he is seen talking to Fairy Godmother and looking at Jane and Carlos De Vil entering. He is the only one (besides Prince Charming and Cinderella) to wear a Cinderellasburg costume.