Grand Duke was a title of nobility on Eiattu 6. Gror Pernon, a leading member of the Priamsta, held the title as of 4 ABY.
During the New Republic era, Pernon encouraged his grand-niece, Plourr Ilo to return to Eiattu 6 with the Rogue Squadron to take back the throne from the impostor Prince Harran.