She is somewhat optimistic compared to other nobles from her kingdom as she did not complain about her hotel room in Loguetown. However, Oda stated that she is likely as bad as her husband. She did show concern for Sterry as she was appalled at Vice Admiral Garp's derision of her husband during the reception of the various royals prior to the Levely.
Nantokanette and her husband later arrived at the Red Port, where she was shocked by Garp's rudeness towards Sterry. They then took the bondola to go up to Mary Geoise. After reaching the top of the Red Line, they made their way to the Mary Geoise castle.
Her name is a reference to Marie Antoinette (マリー・アントワネット,Marī Antowanetto?). The name Nantokanette, ナントカネット, translates to "Something-nette". Oda stated that he was lazy when coming up with it because he believed she would be as bad of a person as Sterry.