The former leader of the Resistance, later one of the members of the Order of the Black Knights, he asks Zero to become their leader. He was friends with Kallen's older brother, Naoto.
He later on leads a betrayal against Zero once finding out about Zero's Geass power, and makes a deal with Brittania in which they will hand over Zero if Brittania returns Japan back to an independent country.
When Lelouch leaves to attack the Geass Order, Villetta goes to the Chinese Federation to confront Ougi, intending to kill him to eliminate her links to the Elevens. She hesitates when Ougi admits his love for her. She is captured after an altercation with Sayoko, but is eventually released and leads Ougi to believe Zero cannot be trusted. She remains with the Black Knights following this. It is revealed that she is pregnant with Ougi's child and she remains on Horai Island when the Black Knights depart to battle Lelouch. At the end of the series Villetta and Ougi are married and Ougi becomes Prime Minister of Japan.