Anya is the Knight of Six, a girl who does not trust her memory. Quiet and always taking pictures of everything, some think that she is harmless, but she is very deadly. Piloting a heavy assault Kinghtmare Frame, Mordred, she can turn situations that aren't deadly into something very deadly.
When the fight for Nunnally occurs she joins the battle to protect her. Since she does not trust her memory she takes pictures of everything and puts them in her blog. Because of her blog she once suspects that Lelouch is a former Britannian prince, but he and his double were seen at the same place so that was dropped. During the battle in the Chinese Federation and the second battle of Tokyo, she has slight memory flashes showing Lelouch and Nunnally playing as children. This was caused by Marianne, who was inside of Anya's heart. Anya was the only true witness of Marianne's
death. When Marianne takes over her body to go meet up with Charles, Anya wakes in a confused state in the middle of the activation of the Ragnarok.
The reason why Anya doesn't trust her memory is because, she has a nine year old diary which she does not remember writing, along with other diary and blog entries that don't match up with her memory. The reason is that the Emperor used his geass on her to make her forget every what she saw happen to Marianne. As she child she spent her days at Aries Palace as an apprentice for proper etiquette.