Nina Einstein is introduced as a bookish member of the student council at Ashford Academy. Nina demonstrates an acute xenophobic reaction to Elevens and is initially intimidated by Suzaku when he arrives in the school. She develops an obsessive crush on the Third Princess Euphemia after the latter helps her during a traumatizing hostage incident at the Lake Kawaguchi Convention Center Hotel. She subsequently comes to rely on Euphemia for emotional support.
Lloyd Asplund is interested in Nina’s personal research regarding the possibility of using Uranium-235 as a fuel, even providing her with some sakuradite to further her research. Following Euphemia’s death, Nina becomes emotionally and mentally unstable. In a misguided attempt to kill Zero and avenge the princess, she arms the Ashford’s Ganymede Knightmare Frame with a prototype nuclear reactor, intending to detonate it and take out all of Tokyo.
It fails to explode, however.
Nina is eventually recruited by Second Prince Schneizel as chief of his “In Vogue” research team headquartered in Dallas, Texas. Schneizel seems to keep her stable by reminding her of how Euphemia would act, though her bitterness towards Zero is not forgotten. Under him, she eventually creates a working bomb. The bomb, codenamed F.L.E.I.J.A. (Field Limitary Effective Implosion Armament, pronounced “Freya”), vaporizes everything within a specific radius. The one used on Tokyo obliterates everything within eight kilometers, while another used on the Britannian capital of Pendragon destroys everything within 100 kilometers. Nina is devastated by the destruction caused by her weapon, which causes more than 35 million casualties when fired on Tokyo Settlement. Lloyd tells her that she’ll have to become detached if she intends to continue being a scientist. She is forced to go into hiding shortly thereafter, as several countries, Britannia included, are searching for her because of her involvement with the creation of F.L.E.I.J.A. Both she and Rivalz are later captured by Lloyd and a number of armed civilians under Lelouch’s Geass control.