After the Black Rebellion, she returned to Britannia and continued her research under Schneizel. She completed the F.L.E.I.J.A. weapon, motivated by her hatred toward Zero, but she deeply regretted the weapon she created when she saw the effects of it. She then turned against Schneizel, who planned to control the world using F.L.E.I.J.A., and cooperates with her enemy Zero.