Duke is a red and black striped frog and serves as Chocolat's magical familiar. As her familiar, Duke is supposed to help her collect as many hearts as possible, but he is often seen lounging on her bed or sleeping instead. Rather than offering helpful advice, he tends to make discouraging remarks. He ends all of his sentences with "-kero," similar to "ribbit" in English. Duke frequently fights with Blanca and often refers to her as a rat.
In the manga, it is revealed that Duke is actually Poivre, Cinnamon's brother. He had turned himself into a familiar to hide from the palace guards who were searching for him because he was hiding Cinnamon. However, the spell backfired, and he became a real familiar. He eventually regained his human form after obtaining a white heart.
