She's the fourth clone in the mass-produced Barshem series, that were based off of Ingram, the Originator's, data. Her codename is "Bet Barshem." She was a spy for the Aerogators that was sent by Ingram, to go to the Earth Federation in order to gather data.
During the second attack at the South Pole; Zengar, Elzam, the Hiryuu Kai and the Hagane manage to destroy the Aerogators' units that were there. Viletta launches, and destroys the Shirogane's bridge, killing all of the officials who were going to surrender to them. It was not revealed to them that she was the one who did it.
Once Ingram betrayed the SRX Team, she became the new SRX Team Commander, and is a Captain rank. She has very good PT piloting skills, and is always able to judge cooly on the battlefield.
During the final battle with Septuagint, Guilliam asks her who she really is. She tells him that her real name is Viletta Plisken, and that she was created from Ingram to act on his behalf once he became unable to act of his own free will. Ingram created her before he was fully taken over by Judecca, and then sent her away to complete his will. She says that she was a double agent, but she doesn't plan on telling the others about it. She goes on to explain to him about the Balmar Empire, and the Aerogators.
After the war with the Aerogators, she joins the Earth Federation Army. Later, along with Guilliam Yaeger and Ryuune Zoldark, she is sent to investigate the White Star.