Villetta Nu 26 years old (27 at R2), is a dark skinned elite Knightmare Frame pilot and subordinate of Jeremiah Gottwald. She becomes a baroness in the second season and she is initially blackmailed into joining the Black Knights.
Villetta makes her first appearance in the first episode of the series when she along with Jeremiah Gottwald enter Knightmare Frames after Prince Clovis la Britannia commands all Knightmare pilots to recover the capsule that was stolen by the terrorists.
Shortly after Lelouch Lamperouge gains the power of Geass, he is confronted by Villetta. Lelouch tricks her into leaving her Knightmare, then uses his Geass to have her turn it over to him, leaving Villetta standing in an empty warehouse confused as to why her Knightmare is gone.
Villetta and the other purebloods within the Britannian Army frame Suzaku for Clovis' death, planning to use him as an excuse to rid the army of Honorary Britannians. Zero reveals himself publicly, and declares it was he who killed Clovis. As a result of Zero using his Geass on Jeremiah Gottwald to force him to assist in Suzaku's rescue, she along with the other purebloods are prevented by Jeremiah to stop their escape.
After Jeremiah is disgraced for helping Zero escape with Suzaku Kururugi, having likewise been compelled by Lelouch's Geass to do so, Villetta remains loyal to him, since she too has experienced similar memory loss after apparent strange behaviour. After Jeremiah's apparent death, she resolves not to die in disgrace as he did. She begins investigating Zero's connection to Lelouch, basing her search on the blurry image of Lelouch she saw in her Knightmare shortly before exiting it. She narrows her search down to Lelouch, and enlists the aid of Shirley Fenette to discover the truth. While Villetta follows her, Shirley discovers Lelouch's secret identity. Villetta nearly succeeds in arresting him, but Shirley shoots her in order to protect Lelouch.
Villetta is saved by Kaname Ohgi, who doesn't realize who she is. Having developed amnesia from the trauma of being shot, Ohgi names her Chigusa and decides to take care of her, since he is unwilling to kill her in cold blood and turning her into the police would draw unwanted attention towards the Black Knights. She seems to fall in love with him as a result, even going as far as telling him that she didn't mind him being an Eleven.
Later On, Villetta regains her memories when she is attacked by a group of rioting Elevens. She is disgusted at the fact that she was romantically involved with an Eleven. She makes her way to Ashford Academy, where the Black Knights have made their headquarters. Ohgi takes her to speak privately, only to be surprised when she shoots him in the stomach. She escapes the compound in a Knightmare Frame.
In the intermediate year, Villetta has been granted the title of Baroness for discovering Zero's identity and is working with the Office of Secret Intelligence. She is employed at Ashford Academy as the gym teacher, placed there to monitor Lelouch for any signs of contact with C.C. She is quite popular within the school, and is also the head of the swimming club, of which Shirley Fenette is a member. She doesn't seem to harbor any ill-will towards Shirley, actually using the fact that Shirley shot her as an example of how much she likes Lelouch. Along with Rolo Lamperouge, she is the only one aware of Lelouch's suppressed Geass ability. After regaining his memories, Lelouch uses Villetta's previous relationship with Ohgi to blackmail her into keeping quiet.
Despite her actions in the finale of the first season, Villetta still seems to care for Ohgi, suggesting that her teaching position is motivated by Ohgi's comment about having been a teacher before the war. When Ohgi is freed by Lelouch in the fourth episode, she breathes a sigh of relief before quickly regaining her normal composure. In the eighth episode, Viletta is constantly looking for Ohgi at the opening ceremony for the Special Administrative Zone of Japan, Lelouch having told her he would attend. When one of the Zero-dressed participants attempts to shoot her, Ohgi, also disguised as Zero, prevents him from doing so. She immediately suspects his identity, but he denies it and bids her farewell.
Despite being blackmailed, she passes up a chance to get rid of Lelouch by knowingly maneuvering Jeremiah into his trap. When Zero leaves to attack the Geass Directorate, Villetta sneaks away to the Chinese Federation to confront Ohgi, intending to kill him to eliminate her links to the Elevens. She hesitates when Ohgi admits his love for her. However, before she can reconcile with him, they are interrupted by Sayoko under the orders of Diethard to monitor Ohgi after which, she engages in combat with Sayoko. When Ohgi is stabbed by Sayoko's kunai and falls off a cliff in an attempt to protect her, she leaps down after him. She is recovered and held hostage by Diethard to ensure Ohgi's loyalty. She is set free during Cornelia's escape and apparently leads Ohgi to believe Zero cannot be trusted. She remains with the Black Knights following a suggestion by Cornelia that nobility is not all that matters.
It is revealed that she is pregnant with Ohgi's child and she remains on Penglai Island when the Black Knights depart to battle Lelouch. At the end of the series, she is married to Ohgi.