rendering the group unable to fight X.A.N.A., putting the entire real world in danger. After what they thought was their defeat, Jeremy receives a coded message from Franz Hopper that allows him to recreate Lyoko and continue the fight against X.A.N.A. In Season 4, Jeremy and Aelita construct a digital submarine, the Skidbladnir, to travel across the Digital Sea to destroy X.A.N.A.'s "Replikas," which are copies of Lyoko's sectors that are linked to X.A.N.A.-controlled supercomputers on Earth, all created for its goal of world domination. X.A.N.A. uses William as its general throughout the season to defend the Replikas and target the Lyoko Warriors in any way he can. To prevent suspicion regarding William's disappearance, Jeremy manages to program a specter to take William's place at Kadic, although the clone has low-level intelligence and acts very stupidly. Near the end of the season, X.A.N.A. decides to draw energy from all of its Replikas to create the Kolossus, a gigantic monster that later destroys the Skidbladnir. Before it is destroyed, Jeremy frees William from X.A.N.A.'s control. After his return, he has a difficult time gaining the trust of the group. While Ulrich defeats the Kolossus, Franz Hopper sacrifices himself to power Jeremy's "anti-X.A.N.A. program," which destroys X.A.N.A. forever upon activation. Shortly after, the group, albeit reluctant due to their nostalgia, decides to shut down the Supercomputer. Characters Lyoko Warriors Jeremy Belpois (French: Jérémy Belpois; formerly Jeremie (French: Jérémie) in season 1) Voiced by: Raphaëlle Bruneau (French); Sharon Mann (English) A 12-year-old (later 13-year-old) top-of-the-class student who finds and starts the factory's supercomputer while looking for parts to build a robot. By turning on the Supercomputer, he reawakened Aelita, the virtual world of Lyoko, and the malevolent multi-agent system X.A.N.A.. His goals are mainly driven by his desire to protect Aelita, whom he has a crush on, and to save her from the Supercomputer and X.A.N.A. by materializing her on Earth. As part of the group, he specializes in programming new ways to defeat X.A.N.A. and monitors the group while they are on Lyoko. Because he is not very athletic and is more computer savvy, Jeremy almost never goes to Lyoko, only going there once and vowing to never do it again. His workaholic attitude occasionally puts a strain on his relationships with the other members of the group. Aelita Schaeffer Voiced by: Sophie Landresse (French); Sharon Mann (English) Mainly known by her