X.A.N.A. (or simply XANA) is the main antagonist and the sworn enemy of the Lyoko Warriors. It is a sentient and dangerous computer program that inhabits the Supercomputer and controls the virtual world of Lyoko. X.A.N.A.'s only desire is to take over the Earth, and destroy the obstacles who stand in its way, the Lyoko Warriors.
After its supposed destruction, X.A.N.A. managed to miraculously revive through the Cortex, becoming even stronger than before in Code Lyoko Evolution.
Ultimate Story 3: Aide from the Past[]
In Ultimate Story 3, XANA was one of the main villains responsible on carrying out the Shadow Queen's Rifter as Fox McCloud, Falco Lombardi, Krystal and Misty (US) visit Lyoko to assist the heroes Jeremie Belpois , Aelita Stones, Yumi Ishiyama, Ulrich Stern, and Odd Della Robbia.