Vivi Ornitier (ビビ・オルニティア Bibi Orunitia), is a fictional user of black magic in the Final Fantasy series, and a main protagonist of Final Fantasy IX. His appearance is directly based on the black mage characters from various other Final Fantasy games. As a result, he is garbed in blue, wears a tall yellow hat, and has no facial features beyond a set of yellow eyes. He did not have a voice until Kingdom Hearts II, where he is voiced by Ikue Otani and Melissa Disney in the Japanese and English versions respectively. The Kingdom Hearts II incarnation of Vivi was designed by Tetsuya Nomura. Vivi was created after the plot of Final Fantasy IX was complete, which was unlike previous titles such as Final Fantasy VII and VIII, which had their protagonists designed before their stories. Because he was a key character to the plot, part of the world design was centered on him.
Source: Wikipedia, "Vivi (Final Fantasy)", available under the CC-BY-SA License.