|"A super dangerous program, like a virus, which can control electricity. And it activates towers on Lyoko to gain access to your world."|
–Aelita about the malevolent artificial intelligence in X.A.N.A. Awakens, Part 2
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 of great power that inhabits the Factory 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.
As a specialized government program, X.A.N.A. has a stealthy form which has become more mysterious and unnatural. When it does reveal its presence, the program uses pulsating energies to spread its connection from the Lyoko Wires to the real world and its Eye will appear on any chosen device screen. However, its spectres seem to be its only physical form as it has incredible processing power and they have the same look:Grey Silouettes with a more swirly eye at the chest. When the spectres show themselves in the real world, X.A.N.A. is able to manipulate solid matter and towards the final episode Fight to the Finish, the program had a more maleable look which demonstrates its shape-shifting appearance.
In Ghost Channel, X.A.N.A. required a perfect physical yet digital form to decieve its enemies and thus it chose Jeremie's form. However, when it was exposed and denied the truth, it changed with its standard shape-shifting features to a demonized version of the teenager, which it had claws, blanked eyes with energy constantly flowing outwards as well as an aura.
When it had possessed William on Lyoko and even additional power from the Core of Sector 5, it used the vast energies to permantly bind itself to his avatar and used its power to transform it into a darker version which the program could now see and act more like the Lyoko Warrior.
When the government was dealing with enemy threats from Project Carthage, X.A.N.A. was created to counteract these outside issues and thus, understand what species to protect. However, due to it learning what humanity was becoming and possible other warfare-related acts, the program separated its side with humans and created an agenda to either cleanse life or dominate it with their technology.
While X.A.N.A. is a unique threat to all life and programmed to be more clever than its enemies, it can make mistakes, was mentioned by Jeremy by being theoretical in order to re-create reality, and even fails at social conversations. Nonetheless, it never gives up and uses a new plan anytime it fails.
With its knowledge from the military and government, it creates several models of Monsters as its form of an army and eventually creates many other war-related machinery for its battles.
In the first season, its attacks are shown in secluded places in order to induce paranoia and make its presence seen once it manages to take over technological property, even going as far to literally completely disrupt motor functions of surrounding humans in Killer Music with our beloved music. Once it learned from its mistakes, it had grown in its intelligence and programming, making new monsters like the Tarantula during Season 2 and would develop a more human-like personality through human bodies with its possession. When X.A.N.A. shows its true personality while acting as a human, it is malicious, deceiving, secretive, lustful, and would act exactly as its host in order to blend in and get what it wants.
During the seasons further, X.A.N.A. appeared to despise the digital world and Supercomputer entirely, using William Dunbar as its most used physical form, infect the Towers with its signature access code to go as far to erase or control it, prevent the Lyoko Warriors from getting close to completing their goal in save the world, and much more. Also, due to the fact X.A.N.A. constantly being exposed to the entire military and hardly ever exposed around the civilians, it had displayed a cruel demeanor, never shown love, always uses weapons and methods of attacking as its answer to everything, and only has a minor form of empathy to life.
Since the rest of humanity is unaware that X.A.N.A. exists, it has determined the Lyoko Warriors as Enemy #1. However, it has made seperated opinions to describe each of their positions as a threat to its plan's.
- Jeremie Belpois: As he found the Supercomputer and Aelita first, X.A.N.A. sees Jeremie as its largest threat and it knows that he would eventually become as smart and devoted to its creator's work. As a fact that Jeremie has potential to win without an avatar, X.A.N.A. sometimes knows that he is a problem and intelligent enough to outsmart it. Also, the program has the most respect for him such as when it copied his appearance as a spectre saying it was "almost proud to resemble him".
- Aelita Schaeffer: Since she is her creator's daughter and it was told to protect her, X.A.N.A. had a different goal in mind and that was to dominate over her position and when it realized that she was becoming too big of a risk to its plans, it implanted a virus to make sure that if it goes out for good once the supercomputer is shut down, she will too. It mainly has a major interest in her abilities so it hunts her down.
- Yumi Ishiyama: X.A.N.A. has the most intention to attack her the most of the team, which it knows her abilities can easily destroy its monsters and is just as smart as Jeremie or Aelita. As William, X.A.N.A. has shown this desire to take her out the most unlike its host whom has an obvious crush on Yumi. She even managed to be clever enough to temporarily "break" it from her friend's mind and understand who of the two was the real source behind the attacks William was supposedly causing.
- Odd Della Robbia: X.A.N.A. sees Odd as the most childish and any attack that he did on his monsters, it wants him taken out before Odd can do anymore harm. The program knows his weaknesses and will use them against him if it has the chance.
- Ulrich Stern: X.A.N.A. knows Ulrich is the best fighter and what speed he possesses. As William, it has shown to understand how to take out Ulrich's arsenal and cope with his actions.
- William Dunbar: As William fell into the grip of X.A.N.A., he was turning more like it and the program would demonstrate its actions through the real William's body and through a long-term bond, it would desire the Lyoko Warrior's superior abilities in going against the group and fulfilling its mission during Evolution.
- Laura Gauthier: Evolution only. X.A.N.A. was less focused on Laura because the rest of the Lyoko Warriors never trust her. However, X.A.N.A. was surprised that Laura figured out its strategy in Rendezvous.
- Eva Skinner: In the Chronicles novel series, Eva joined their group of friends, but was really X.A.N.A.'s possessed pawn in order to destroy the group from within.
As X.A.N.A. knows that Franz understands how to defeat it, the program developed a huge interest in taking out its creator. They both became part of the digital world and the creation intends to keep everything "he" knows for itself and take over the world, since its own abilities are restricted with its knowledge over technology and the real world.
X.A.N.A. and Lyoko were both created by a computer genius named Franz Hopper, formerly Waldo Franz Schaeffer. He created it to destroy Project Carthage, a military project designed to disrupt enemy communications. Along with X.A.N.A., Franz also created the "Temporal Reversion" program, which he used to give himself all the time he needed to perfect the virtual world. Throughout the reversions, X.A.N.A.'s intelligence grew exponentially, showing signs of self-awareness and curiosity which it directed to Franz, who was eventually driven into paranoia because of his abuse of the time reversions. He'd spent almost 7 years worth of reversions concerning the date of June 6th, 1994, but by his 1,265th use, X.A.N.A.'s presence had already started to set in.
X.A.N.A. eventually betrayed Franz after the 2,546th return in time. It alerted the men in black to Hopper's location, forcing him and his daughter to retreat to Lyoko. X.A.N.A. then seized control the Supercomputer, and made Franz and his daughter prisoners on Lyoko. Hopper tried to reason with X.A.N.A. that they could live in peace, but X.A.N.A. ignores his pleas and tries to kill him and Aelita. To prevent X.A.N.A. from using Lyoko to wreak havoc on the Earth, Franz Hopper was forced to shut down the Supercomputer to stop X.A.N.A., forcing him, Aelita, and the hostile program into dormancy.
X.A.N.A. was reawakened in the prequel episode by Jeremie, who reactivated the Supercomputer, and discovers Aelita, Lyoko, and deadly monsters. As soon as it became active along with the Supercomputer, X.A.N.A. activated a Tower in the Ice Sector. Through the Tower, X.A.N.A. affects the real world by projecting electric shocks through the network and possessing machines and wires to attack the teenagers who know about the Supercomputer. After that, X.A.N.A. creates a living electricity monster to eliminate them. Jeremie virtualizes Odd, Ulrich, and Yumi onto Lyoko to fight the monsters, ensure Aelita gets to the red Tower, and she deactivates it through the interface. They discover that the attacks and monsters were the work of X.A.N.A., which they learned has the ability to activate Towers to gain access to the real world.
Season OneX.A.N.A. uses simple-minded methods in the first season. It activates Towers to launch random attacks against the city and the group, and uses monsters and programs in the virtual world to fight the Lyoko Warriors and eliminate Aelita, the only person who can deactivate its Towers, and stop her materialization so they won't unplug the Supercomputer.
Its next attack is in Teddygozilla, which involves possessing Milly's teddy bear and turning into a giant monster to attack random humans. On Lyoko, Aelita and Odd get past the monsters, deactivate the Tower, and a return to the past erases the damage caused.
X.A.N.A. attempts nuclear sabotage in Seeing Is Believing. It creates power failures all over the city to steal electricity from the city's substations, then unleash all of it's concetrated power on a nuclear power plant, creating a short-circuit that would cause a nuclear meltdown and wipe out the whole region. On Lyoko, X.A.N.A. hides the Tower's path under the illusion of an oasis in the Desert Sector.
In Holiday in the Fog, X.A.N.A. knocks over containers filled with toxic substances, making living clouds of poison gas to spread all over the city.
X.A.N.A. possesses the bus that Ulrich and Odd ride in Log Book. It tries to crash the bus towards a petrochemical plant, threatening to blow up a part of the city. On Lyoko, X.A.N.A. programs a virtual sandstorm to cloud the group's vision, and causes the ground to split apart to try to make them fall into the Digital Sea.
It interferes with the country's digital infrastructure in Big Bug. This causes minor problems with electronic systems, but it's real goal is to get an automated freight train carrying deadly toxins placed on the same track with another automated train. If they crash, the toxins will be released and spread out into the air, creating an ecological disaster on the city.
In Cruel Dilemma, X.A.N.A. goes for a more direct approach, by possessing two bulldozers and using them to try and demolish the Factory. Its aim is to wreck the computer interface and the Scanners, meaning no more communication with Aelita or transfers to Lyoko, preventing any more resistance against it.
X.A.N.A. tries an infiltration tactic in Image Problem. It captures Yumi with a Guardian, and fools them into thinking she was devirtualized. With the Tower, X.A.N.A. has really materialized a clone of her into the real world. The evil clone causes trouble with them and convinces them to go to Lyoko. Inside the Scanner room, the fake Yumi tries to unplug the Scanners to leave them with no way to return. The others free the real Yumi and she fights her clone, while the others deactivate the Tower.
The next attack in End of Take involves taking over an animatronic alien meant for a movie, and send it to hunt down the group. On Lyoko, X.A.N.A. creates a fake Tower next to the real one to confuse Aelita.
X.A.N.A. captures Aelita with a Guardian in The Girl of the Dreams. At the same time, it possesses Yumi's samurai armor to attack the group. The group searches for Aelita on Lyoko and free her, while Yumi keeps the living armor at bay until she deactivates the Tower.
In Plagued, X.A.N.A. possesses rats and unleashes an army on the school to eat the students alive. On Lyoko, it tilts the slope of the plateau on Lyoko to make it difficult to fight monsters. Then, it later tries a similar attack using swarms of hornets in Swarming Attack.
In Just in Time, X.A.N.A. generates waves of ultrasound out of electrical sockets all over the city, which can shatter objects, cause small earthquakes and structural damage to buildings.
In The Trap, X.A.N.A. tries to trap the group inside the Factory using it's mechanical systems, specifically the elevator and the assembly line. Jeremie and Odd are lured into the assembly line, and are attacked by it's machines, while it holds the rest prisoner in the elevator. It overloads the boiler to make it explode for Odd and Jeremie, and makes the elevator fill with water to try and drown Ulrich.
X.A.N.A. possesses containers of laughing gas to send clouds of them after the group in Laughing Fit. A small amount gets into Odd's Scanner as he is virtualized, severely weakening him on Lyoko, and chases Jeremie away from the lab interface.
Instead of attacking the city, X.A.N.A. sets a trap for the group in Claustrophobia, where it electrifies the cafeteria's walls and ceiling, preventing Ulrich, Odd, and other students from escaping. Jeremie and Yumi finished lunch earlier and left before they were trapped along with them, and stopped the building from collapsing.
In Amnesia, X.A.N.A. possesses a machine that generates microscopic robots to make its own nano-viruses that cause memory loss when one is infected. It planned to let this virus spread out into the world, pacifying the human race for X.A.N.A. Ulrich was the first victim along with several others, who goes to help his friends despite his amnesia.
X.A.N.A. attacks humans directly in Killer Music. It creates a music file, which is made to transmit a biological signal that puts anyone who listens to it into a coma, and will die within several hours. It also uses the media for maximum coverage, and eventually gets to the lab too. Aelita deactivates the Tower before everyone in the city is wiped out.
In The Robots, X.A.N.A. builds deadly robots using the machines in the Factory. It has one download the identities of the group from the lab interface, then wreck it to prevent them from using it. X.A.N.A. sends the robots after the group at the school. But, the interface was easy to fix thanks to Jeremie.
Its next attack in Zero Gravity Zone involves controlling gravity through the use of the electrical networks. Using street lights, X.A.N.A. creates electromagnetic fields to upset the magnetic attraction of the Earth, which alters the gravity fields around targeted areas, making objects and people float endlessly in the sky. It hacks many power stations to gather enough energy, so it can concentrate an enormous field around the soccer game, where it planned to use on the group and several others.
X.A.N.A. tries to eliminate the group on Lyoko in Routine. It activates a Tower to infect the Supercomputer itself this time, stopping devirtualization and making it so they will disappear forever if they lose all their life points. When Jeremie tries to work on the hardware, X.A.N.A. locks him out of the elevator and gives him a shock when he starts messing with the Supercomputer's circuits. Aelita deactivates the Tower.
In Rock Bottom?, X.A.N.A. melts the ground around buildings in the city, causing them to sink into the earth, including the school buildings.
In Ghost Channel, X.A.N.A. traps the three warriors inside a Simulation Bubble as they were stopping a different attack. It fools them into thinking they are living on Earth, but they are really stuck inside a virtual simulation. X.A.N.A. poses as a fake Jeremie to try to get them in the fake Scanners to delete them once and for all. The real Jeremie virtualizes himself inside of the simulation, and convinces the others that he is the real one, because X.A.N.A. is a mere program and could never fully understand the nature of their friendship. It tries to kill them inside the simulation, but Aelita dispels the bubble with her Creativity in time.
X.A.N.A. tries to stop Aelita's materialization when it is finally complete in Code: Earth. It sends monsters to attack the group, and Megatanks for the Tower that they are using for the process. This has failed, but X.A.N.A. managed to secretly take a piece of her very being to keep her linked to the Supercomputer.
In False Start, after Aelita was made flesh and blood, the group discovered the alteration that X.A.N.A. made to herself, mistaking it to be a virus implanted in her. When they tried to shut the Supercomputer down, Aelita gets put into a lethal coma, but comes back to life when it's turned on. X.A.N.A. launches its biggest attack as this happens, using a Scanner to send Kankrelats to Earth and attack the school. Jeremie shuts down the infected Scanner, and Aelita deactivates the Tower.
Season TwoX.A.N.A. is growing smarter and more powerful. It will be able to create new monsters, possess human beings, and pursue more complex and larger schemes. Moving beyond random attacks, X.A.N.A. now seeks to steal Aelita's digital memory at any cost, using its new Scyphozoa monster. It now launches attacks as simply a means to get her virtualized, and make sure it can steal her memory without interference. Also, when the group discover Franz Hopper's diary, X.A.N.A. tries to stop them from gaining any new knowledge from his notes.
In the starting episode, New Order, X.A.N.A. shows its growing strength by creating a new monster called a Tarantula, and it successfully takes out all three of the Lyoko Warriors in its introduction. When X.A.N.A. sees Aelita wander into a mysterious house called "the Hermitage", it sends a spectre to knock her out and use as bait for her friends, and then possess the house when the others come for her. X.A.N.A. makes the house throw inanimate objects at them, then tries to lead them into a sauna and boil them, but only catches Ulrich and Yumi. The attack is thwarted before they are boiled alive.
In Uncharted Territory, X.A.N.A. sends Aelita to a mysterious new sector to try and have her memory drained. When X.A.N.A. sees her alone on Lyoko, it sends monsters to lead her to the edge of the Forest Sector. It then sends a strange orb to transport her to a hidden sector called Carthage, then uses Creeper monsters to hold her down, and the Scyphozoa monster to grab her with its tentacles and steal her digital memory. The others save her life and escape successfully.
X.A.N.A. attacks the Lyoko Warriors as they explore the new sector in Exploration. Its Creepers devirtualize Odd and Ulrich, but they can't materialize into the real world because they are not registered for the Carthage Sector. It also traps Aelita within its walls and sends the Scyphozoa after her. It programs a laser trap for Yumi, but she gets past it and saves Aelita. They discover that Carthage is where X.A.N.A. lives, and where all of virtual world's data can be accessed. It hatches the flying Mantas to deal with them, but Aelita escapes and the rest of the group is materialized successfully.
In A Great Day, X.A.N.A. takes over the return in time program. When the group recovers data from Carthage, X.A.N.A. plants a trap inside of the information, a virus that lets it take control of going back in time. X.A.N.A. starts launching repeat return trips, and activates a Tower on Lyoko. The last trip leaves Aelita alone on Lyoko, then X.A.N.A. unleashes a spectre to possess Sissi. It has her take Jeremie to an isolated place, while the Scyphozoa attacks Aelita. When they stop the return trips and shut down the Tower, Sissi returns to normal with no memory of what she was doing. This reveals to the group that temporal reversions will increase X.A.N.A.'s power, which is how it became strong enough to possess and control human beings.
In Mister Pück, X.A.N.A. possesses Jeremie. Aelita's mysterious visions lead the group to a briefcase of compact discs that contain Franz Hopper's notes. X.A.N.A. spies on Jeremie and sees him with the case through his computer. Taking action, it tries to possess one of the group. It fails with Odd and Ulrich, but succeeds with Jeremie. X.A.N.A. has him destroy the discs, then kidnap Aelita and bring her to the Factory. The others rescue Aelita, and Jeremie fights Odd with new pixelated powers. Once Jeremie returns to normal, they learn that people who have been virtualized to Lyoko a few times cannot be controlled by X.A.N.A. Jeremie is then virtualized as a warrior to protect himself, with the experience having been most displeasing for him.X.A.N.A. makes a special necklace to control Aelita in Saint Valentine's Day. A possessed delivery boy leaves the necklace in front of her room. She wears it, thinking it to be a gift from Jeremie. X.A.N.A. activates a Tower, in which Aelita's necklace projects a special virus to control her mind. She convinces Jeremie to send her to Lyoko. She then heads straight for the Scyphozoa. This plan fails when Jeremie tells Odd to shoot her, gambling that X.A.N.A. wouldn't risk her life until it gets her memory. X.A.N.A. falls for their bluff and the Scyphozoa lets her go. Aelita turns back to normal, and she deactivates the Tower. They smash the necklace, and find a chip which is the source of the necklace's power.
In Final Mix, X.A.N.A. kidnaps Aelita to try to get her memory. It possesses Jim Morales and and makes him bring Aelita to the lab to virtualize her where it wants her. X.A.N.A. uses Jim and sends monsters to provide interference as the Scyphozoa drains her memory. She was saved by Ulrich in time.
X.A.N.A. attempts to trick Aelita into exposing her memory in Missing Link. During a mission to Lyoko, the Scyphozoa appears and attacks Yumi instead. It takes her DNA sequence, leaving her unable to be rematerialized into the real world. Without thinking, Aelita recklessly uses a process to transfer her sequence to Yumi's own, but she doesn't know this alteration will expose her memory for X.A.N.A. to steal at will. She is stopped by the other warriors and they find Yumi's missing sequence in Carthage's data.
In The Chips Are Down, X.A.N.A. tries to eliminate the team on Lyoko this time. It creates a massive army of Krabs on Lyoko, then possesses Nicholas to make him use the lab interface to changes the rules of battle, making it so the warriors get wounded for real until they succumb to the pain. Jeremie undoes the change, but the Krab army tries to block access to the tower. Ulrich clears a path to get Aelita through.
X.A.N.A. acts out of mutual interests with the Lyoko Warriors on two occasions next. The first was in Marabounta, when Jeremie creates his own monster program to keep X.A.N.A. at bay. It works well at first, but his monster eventually starts targeting Aelita because she is still not fully human yet. To their surprise, X.A.N.A. sends monsters to protect her, because it still needs her memory and can't let her die yet. It also helps the Lyoko Warriors destroy the Marabounta. Once the threat has ended, the monsters leave them without a fight this time.
It once again needs their help in Common Interest. The Supercomputer's nuclear battery power has nearly depleted, threatening to shut down forever, and putting X.A.N.A. and Aelita at risk of dying. X.A.N.A. acts by possessing a criminal and have him steal a uranium battery, then kidnaps Jeremie to force him to change the battery, certain Jeremie will do it to save Aelita, because X.A.N.A.'s vessel depends on the Supercomputer being online to stay conscious. Once Jeremie replaces the battery, he is no longer of use, and the possessed human now tries to kill him. They deactivate the Tower in time.
X.A.N.A. launches an attack that is directed at Jeremie in Temptation. He tries out a device that he thinks will increase his own intelligence using temporal reversions, but he worsens his health in the process. X.A.N.A. keeps launching attacks to get him to launch more return trips. When Jeremie needs to go to the hospital, it possesses the ambulance and makes it speed towards the river. Aelita, Ulrich, and Odd deactivate the tower, and a return to the past saves Jeremie and Yumi.
In A Bad Turn, X.A.N.A. sends real Krab monsters onto Earth. Each one materialized sacrifices a Scanner in the Factory. It deliberately leaves one Scanner intact, so the group could virtualize Aelita first before anyone else. In that instant, it creates another Krab and wrecks the last Scanner, thus leaving her with no one to protect her from the Scyphozoa. The three Krabs are sent to Yumi's house, the school, and in the above portion of the Factory to deal with rest of the teenagers. X.A.N.A. thinks Aelita is vulnerable without her friends, but it underestimates her skill and fails again.
X.A.N.A. launches a zombie attack in Attack of the Zombies. X.A.N.A. possesses Odd's dog, Kiwi, and modifies him, so that when he bites someone, that person gets turned into a zombie. It tries to zombify the entire school and to get Aelita to Lyoko with the fewest bodyguards possible by biting Odd, but not Jeremie or her. The dog then goes after Jeremie after he completes their virtualization. Also, later into the battle, it makes the entire plateau invisible to confuse the group. Aelita can sense the path, and takes advantage of the fact that monsters still won't dare try to fire on her to get to the Tower.
In Ultimatum, X.A.N.A. uses hostages to coerce Aelita into giving up her memory. It takes control of Principal Delmas, so he can kidnap Yumi and Odd and take them to an abandoned refrigerator warehouse. X.A.N.A. then gives Jeremie its ultimatum through his mobile. Ulrich saves them by using Jeremie's new EMP bomb, which temporarily knocks out the possessed Delmas. He regains consciousness, and now chases and attacks the escapees at the Factory even as Sissi helps them. Aelita deactivates the Tower in time.
X.A.N.A. attempts to divide and conquer in X.A.N.A.'s Kiss. It creates a polymorphic spectre, a ghost that can change forms at will. The spectre turns into different members of the gang and kisses people to sow jealousy between them, and then tricks Aelita into going to Lyoko while they are distracted. They discover its true nature, and the polymorph fights them. During the fighting on Lyoko, X.A.N.A. deletes the bridge to the Tower after Aelita crosses to isolate her with the Scyphozoa. She is saved by Ulrich, and she deactivates the Tower.
In Vertigo, X.A.N.A. attacks with a possessed pack of wolves in the woods when a failed anti-virus that Aelita is injected with makes her invisible in the real world and unable to enter Towers. This gives the Scyphozoa a chance, but she is saved. Jeremie restores her own signature in time to shut down the Tower.
X.A.N.A. manipulates the weather for another scheme in Cold War. It triggers Towers on Lyoko one after another to fake an malfunction, so Jeremie and Aelita would stay in the lab to try and fix the problem, while the rest go to lunch. X.A.N.A. then has a spectre possess clouds in the sky to create a deadly blizzard on the city that goes below freezing level, trying to trap the heroes at school and get Aelita to go to Lyoko alone. When Odd manages to get to the Factory and virtualized, Flying Mantas suddenly appear on Lyoko and create minefields to block escape from the Scyphozoa and access to the tower. Odd uses a Manta to start a chain of mine explosions that open a path to the tower.
In Déjà Vu, X.A.N.A. messes with Aelita's mind. It activates a Tower to show Aelita mental visions of her former life using her link to the Supercomputer. This compels Aelita to go to Carthage to find answers. She willingly takes the bait and lets the Transport Orb take her when it's called by X.A.N.A., despite Jeremie's protests. The Scyphozoa attacks her twice during this trip, and is stopped both times.
In Tip-Top Shape, X.A.N.A. possesses the nurse Yolanda. Jeremie decides to test out an experiment which will give a person the powers of a pixelized human. Odd volunteers, and is enhanced by a spectre of Jeremie's design using an active Tower in the Mountain Sector. At first, he fights well against Yolanda, but X.A.N.A. takes control of Jeremie's Tower, using it to overcharge his energy until it kills him. While Aelita and Yumi help Odd first, X.A.N.A. cloaks the Mountain Sector in impenetrable fog. They save Odd in time and deactivate the original tower in the end.
In Is Anybody Out There?, it creates a ghost monster, and has it go after the heroes. It has also corrupted the Superscan, so they can't detect the activated tower. Ulrich decides to stay on Earth to protect Jeremie from the ghost, and Yumi, Odd, and Aelita are sent to Lyoko. Yumi and Aelita go to Carthage to try to fix the Superscan while Odd searches for the tower in the other four sectors. The girls fail to push the key, and Aelita is left alone with the Scyphozoa. Odd is devirtualized, but gets up to the lab to send the Transport Orb for her before she is caught. She deactivates the tower in the Ice Sector, and a return to the past fixes the Superscan.
X.A.N.A. poses as Franz Hopper to manipulate them in Franz Hopper. It uses the one, undetectable Tower in Carthage to generate a spectre as Franz Hopper, the mysterious creator of Lyoko. The spectre turns the entire group against Jeremie, saying the Scanners were too dangerous. He sends the three to Carthage to get the presumed anti-virus data. The trap is sprung when he virtualizes Aelita in the Desert Sector. He devirtualizes the group's weapons, shuts off the Scanners, and leaves Aelita with the Scyphozoa. Jeremie has seen through its nature, and had a decoy be drained instead. The clone reverts to a ghost and retreats for now. Jeremie restores the Scanners and their weapons, and sends Aelita to Carthage. However, the spectre returns and tries to suffocate Jeremie to death, only to fail when Aelita deactivates the Tower.
It tries to prevent contact between the group and Franz Hopper in Contact. Hopper activates a Tower to possess Sissi, using a white Tower on Lyoko, but she speaks in a unknown language. X.A.N.A. sends Megatanks to attack his Tower, and possesses a doctor to try and eliminate the spellbound Sissi. The latter makes Aelita go off on her own to deactivate X.A.N.A.'s Tower, which leads to her being targeted by the Scyphozoa. Odd wards them off before they get to her, and she deactivates the Tower.
X.A.N.A. plans to take over the group's operation to decrypt all of Franz Hopper's notes in Revelation. It has a polymorph ambush Odd, and lock him in a pit at the Hermitage that slowly fills up with water. The spectre then takes Odd's place on Lyoko. As they activate a Tower to launch the decryption, X.A.N.A. springs its trap as the spectre attacks the warriors, while X.A.N.A. tries to take control of their Tower. If successful, X.A.N.A. will gain access to the restricted part of the Supercomputer, which holds both Franz Hopper's data and all of the Lyoko Warriors' combat gear and essential programs. It has three Tarantulas guard the Tower's wires from Ulrich. X.A.N.A. has taken out all the obstacles, but Franz Hopper interferes, uses his influence to take control of the Tower away from X.A.N.A., and runs the decryption at full speed. It withdraws its monsters away, defeated.In The Key, the group discovers that Aelita holds the keys to Lyoko inside of her, which is the piece of Aelita's memory that X.A.N.A. seeks. With the keys, it can escape the Supercomputer and access the world network. Jeremie also finds the true cause of her link to X.A.N.A., which is not a virus, but a stolen fragment of herself. He discovers the piece in Carthage, and they go to get it back. They succeed in finding it, however; the fragment was revealed to be a false object made to lure them here. The entire room falls apart around Aelita to devirtualize the warriors. The Scyphozoa appears, only with nothing left to stop it this time. With her entire memory siphoned, she drops to the floor, completely drained of life. With the keys in hand, X.A.N.A. activates Towers in all four sectors which render Lyoko nonfunctional, and finally undoes its containment. It then escapes into the world network with all of its accumulated power. Even though Franz Hopper managed to restore Aelita and Lyoko, X.A.N.A. is now free from the Supercomputer, and shutting it down won't stop it from doing what it wants anymore.
X.A.N.A. is now free to explore the world network as part of its own agenda. To keep the Lyoko Warriors from tracking its movements, X.A.N.A. launches more ruthless attacks to destroy Lyoko itself, now that it's no longer bound to the Supercomputer. It attacks the Core of Lyoko in Carthage, while distracting them with its Earth attacks. X.A.N.A. also destroys the sectors one by one to block their access to Carthage by controlling Aelita's mind with the Scyphozoa, and tries attacking the Supercomputer itself in the real world.
In the starting episode, Straight to Heart, X.A.N.A. sends monsters to an unexplored room in the Carthage Sector. The group find the monsters firing on a floating blue orb covered with shields, which they identify as the Core of Lyoko. They stop the assault and save the Core.In Lyoko Minus One, X.A.N.A. possesses a bus full of students, teachers, and the driver and pits them against Yumi. When Aelita goes to the Forest Sector to deactivate the Tower, the Scyphozoa attacks Aelita, and possesses her mind. She enters the sector's Way Tower, and inputs a special code in the Tower's interface, making the Forest Sector disappear and the Tower with it, which turns the class back to normal. X.A.N.A. intends to cut off their access to Carthage, by destroying all the sectors.
It launches another attempt on the Core of Lyoko in Tidal Wave. It creates a monster made from piles of possessed food supplies in the real world, and modifies the Digital Sea on Lyoko and makes it rise and submerge the Mountain Sector, trying to block access to the Tower and the Transport Orb, and ensure no interference as its monsters attack the Core of Lyoko. They return the sector to normal, protect the core, and shut down the tower.
X.A.N.A. tries to destroy the Supercomputer in False Lead. It hacks into a weapons manufacturing computer network and leaves a trail pointing to him, attracting two government agents. When the agents track Jeremie to the Factory and capture him, X.A.N.A. possesses both of them for its true plan. It uses one to keep him occupied, while the other agent successfully unplugs the Scanners and tries to destroy the Supercomputer, to get rid of Lyoko and the group at once. The attack was stopped, and Supercomputer was damaged, but was still functional enough to trigger a return trip to the past.
In Aelita, X.A.N.A. planned to distract the group using an activated Tower, while its monsters attack the Core of Lyoko undetected. But, unbeknownst to it at the time, Aelita and Odd secretly go on a trip to Carthage to access data about her father. Lucky for them, their unauthorized trip has allowed them to discover its plan.
In The Pretender, X.A.N.A. controls a flock of pixelized crows to attack the group. The birds critically injure Yumi. While Aelita deactivates the Tower, the birds attack Jeremie to stop any return trips as the Scyphozoa possesses Aelita. The group fails to stop the brainwashed Aelita from wiping out the Desert Sector, leaving Lyoko with two sectors left, the Mountain and Ice Sectors.
X.A.N.A. tries to destroy the Factory by using explosives in The Secret. It possesses a demolitions worker equipped with a bag full of charges and a detonator, planting them all across the inside for maximum effect. The Tower was deactivated, but the Scyphozoa possesses Aelita after that, which is stops them from launching a return trip to get rid of the explosives, because it won't undo her possession. Yumi stops Aelita in time before she erases another sector, and the unexpected William Dunbar, disarms the detonator.
X.A.N.A. uses a hallucinating virus within the combined beams of two Mantas in Temporary Insanity, and sets it onto Ulrich and Odd. They suddenly act like they're fighting on Lyoko back on Earth, seeing and believing that they are on the virtual world with their friends, and that any other people are monsters. The virus also works the other way around on Lyoko. This is another scheme designed to keep the group busy while X.A.N.A. attacks the Core of Lyoko. Their affliction has been dispelled by Jeremie, and the Core was protected.
In Sabotage, X.A.N.A. tries to crash the Supercomputer's systems through sabotage. It possesses the gardener, has him sneak into the lab, and slightly scorch the memory cards in the Supercomputer with electricity. This act will cause the entire system to crash given time. X.A.N.A. also possesses the tree roots in the forest in the park to try and hold them up from fixing it. The activated tower being used for the attack is also taking up computing resources, which is stopping Jeremie from rebooting the system. Left with no choice, Aelita deliberately uses the Way Tower to sacrifice the Ice Sector and the activated Tower with it, so she can give the Supercomputer enough power to reboot. This leaves only the Mountain Sector left.
X.A.N.A. uses Ulrich's virtual body to attack the Core of Lyoko in Nobody in Particular. Jeremie tries to virtualize him directly into Carthage. The attempt fails and separates Ulrich's mind from his body. Since his own body is now left without a mind, X.A.N.A. is free to take control of it. It upgrades the body's weapons and makes it attack the Core, guarded by Mantas. Ulrich's body is devirtualized and reconnects with his spirit.
In Triple Trouble, X.A.N.A. attacks when it discovers Odd's three unstable clones. It creates ground-based clouds of smoke that turn humans to stone who are currently on the ground floor. Its goal is to immobilize all three of them, so they can't get to the Scanners to be fused back together and he will disappear forever. The three successfully get to the lab and they deactivate the Tower.
X.A.N.A. uses a spectre of Jeremie to destroy the last surface sector in Double Trouble. The clone assaults the real Jeremie, and tricks Aelita, Yumi, and Odd into getting virtualizing them. The clone then uses the lab interface to bug up their virtual forms, making them powerless to stop the Scyphozoa from possessing Aelita. The real Jeremie fixes the bugging, but they are too late. She enters the Way Tower, and destroys the Mountain Sector, completely cutting off access to the Transport Orb. With this, X.A.N.A. is now free to attack the Core of Lyoko. However, Jeremie completes his program to send the group to Carthage directly.In Final Round, X.A.N.A. wastes no time in attacking the Core of Lyoko. After the group initiates William, only he and Aelita are the only ones available to defend the Core of Lyoko at the time. During William's first mission, he gets cocky as he is fighting monsters. X.A.N.A. sees his power, and uses the Scyphozoa to successfully possess him, and makes him go to the Core chamber. He stands at the head of a Creeper attack force that is focused on the Core of Lyoko. With their combined firepower, the monsters take out the core's shield layers one by one. Despite their efforts, they fail to stop X.A.N.A. from destroying the Core of Lyoko, which occurs by William's own hand, and seemingly puts an end to their interference once and for all. In the Digital Sea, William's virtual spirit floats in an empty limbo and is transformed into a darker version of himself.
X.A.N.A. has built virtual worlds inside hundreds of supercomputers in the world network to expand its power, having a plan for world domination. It has also brought back William and turned him into its pawn with modified abilities, programs, and equipment. With its plans now reaching fruition, X.A.N.A. now focuses on eliminating the group using any methods possible, and targets Franz Hopper, the greatest danger. It deals with him by trying to throw Aelita into the Digital Sea, knowing that Franz would willingly expose himself to be targeted in order to rescue his daughter.
In William Returns, the starting episode, X.A.N.A. materializes William through the scanners, which is possible without a tower. He comes back through a Scanner on his own when the group succeeds in recreating the Carthage Sector. William acts normal, then reveals that he is possessed by X.A.N.A. when he kidnaps Aelita. William virtualizes himself and Aelita into Carthage, and takes her to an empty Desert Sector to throw her into the Digital Sea. When Odd saves her, William dives in to run back to his new master.
In Double Take, X.A.N.A. uses William to seize control of an activated Tower. Jeremie uses a protected Tower this time to create a clone of himself for his own uses. But, X.A.N.A. has given William his own Tower control abilities, which he uses to turn the Tower's functions over to his master. They both fight for control, but William eventually overpowers Jeremie's defenses. X.A.N.A. makes the Jeremie clone attack the group, and William guards the Tower with monsters until they deactivate it.
X.A.N.A. creates a polymorphic spectre to kidnap Aelita in Opening Act. It takes the appearance of Chris, the Subdigitals' drummer, and sends her to William on Lyoko. Jim and Chris end up fighting the spectre while the rest of the group deactivate the Tower.
X.A.N.A. takes control of the group's William clone in Wreck Room. They try to use a program to free the real William, but it malfunctions and bugs up files in the Tower which generates the clone. This weakens the Tower's security, prevents deactivation, and makes it vulnerable to X.A.N.A.'s influence. It takes control and has the clone attack the group. They deactivate the Tower in time.
While Jeremie constructs a new virtual ship, X.A.N.A. attacks with monsters and William in Skidbladnir. It sends them to the new, reprogrammed Carthage on a mission to destroy the ship before its construction is completed. The assault was only narrowly thwarted in the end.In Maiden Voyage, the group give their ship its first test run going into the Digital Sea. Their navigation is disabled during the trip, and they stumble upon a new virtual world in the network. X.A.N.A. introduces its new sea monsters in the Digital Sea to attack them, called Kongres.
X.A.N.A. attacks with a spectre as Jeremie teaches Ulrich, Odd, and Yumi to operate the Supercomputer in Crash Course. During their lesson, it knocks Jeremie out cold, leaving the three of them unable to rely on him this time, and attempts to capture Aelita again and send her to William and his group of monsters. They warn Aelita, defeat all of the enemies, and deactivate the Tower on their own without Jeremie's help.
X.A.N.A. counterattacks as the group investigate the Replika they discovered in the episode Replika. It contains a small virtual world that consists entirely of the Forest Sector. Megatanks arrive to try and destroy their ship, which is their only connection to the Supercomputer. William also appears for a chance at capturing Aelita. They finish their mission in the end.
In I'd Rather Not Talk About It, X.A.N.A. once again targets the Core of Lyoko. It possesses a wild pig to attack the group in the forest, and sends monsters and William to destroy the Core. X.A.N.A. also renders the activated Tower invisible to confuse their sense of direction.
In Hot Shower, X.A.N.A. launches a scheme to attack with a meteor shower and capture Aelita as it happens. It takes control of a military satellite, so it can use its laser to split a passing comet into shower chunks that will rain upon the Earth, aiming the bulk of them directly at the Factory. X.A.N.A. also traps the Skidbladnir in a firewall, so it can capture Aelita when the Skid runs out of power. They escape and try to shut down the Tower, but the monsters and William are too much for them. Jeremie tries to hack the military satellite that X.A.N.A. is using with Yumi's help in order to destroy the meteor, but X.A.N.A. is a flawless program while Jeremie is only human. Aelita takes a risk by having Odd devirtualize her, sending her back to the Factory where the meteors will hit, gambling that X.A.N.A. wouldn't dare try anything that would kill her, because it still needs her alive. It destroys the comet with the satellite laser, saving the city and giving up on its attack.
It uses the Scyphozoa to attack the Skidbladnir in The Lake. When everyone except Yumi go to a small island, where Jeremie can't connect to the Supercomputer, X.A.N.A. creates a spectre that inhabits the water and controls lightning, while it uses the Scyphozoa to drain the Skidbladnir's energy. The lake creature's electrical discharges eventually create a storm that will soon incinerate everything on the island. Aelita activates the Skid's shield defense program to destroy the Scyphozoa, and stops the attack.In the episode Lab Rat, X.A.N.A. protects the supercomputer that holds its Forest Replika from the group. Jeremie uses a "teleportation" process to send the group to the Replika's location in the real world. They connect the Skid to a Tower, and he sends them to the laboratory in the Amazon jungle that holds the supercomputer. While inside, they learn that X.A.N.A. has possessed scientists making cybernetic spiders. William takes out the warriors guarding the Skid, then enters and inputs the X.A.N.A. code into the tower's interface, allowing X.A.N.A. to take control of it, disconnect their ship, and sever their link to the real world. The group is left with no choice but to retreat and abort the mission.
They set out to complete their unfinished mission in Bragging Rights. X.A.N.A. activates a Tower to use the cybernetic spiders to deal with the teleported heroes, while it sends William and monsters after the Skid. Ulrich destroys the power supply, which starts to make the sector disappear, but a backup generator activates and regenerates the Replika. William comes back, and monsters fire on the Skid. Odd ultimately defeats William single-handedly, takes out the spider robots, and destroys the supercomputer all by himself.
In A Lack of Goodwill, William materializes from a Scanner while the heroes are busy infiltrating the next Replika, who is sent by X.A.N.A. on a mission to destroy the Supercomputer down below. However, the William clone shows up with Milly and Tamiya. The clone and the original fight each other, forcing him into the elevator. Instead, William goes to the lab interface in order to mess with the system. William uses the interface to shut off the Scanners, get rid of the clone, and shut down the Supercomputer's cooling system to make it overheat and melt down. X.A.N.A. sends new Shark monsters in the network to delay the Skid. William restarts the Scanners to retreat back to Lyoko. Aelita stops the overheating process in time and saves the Supercomputer.X.A.N.A. tricks Aelita using her emotions in Distant Memory. It pretends to be Franz Hopper and sends her an electronic message, saying that he is expecting her on Lyoko, then her computer suddenly bugs up. Aelita goes and enters a Simulation Bubble containing a replication of Aelita's childhood home. By noticing that her mother wasn't programmed into the simulation, she quickly learns this is a X.A.N.A. trick. William was waiting for her inside to capture her. X.A.N.A. tries to trap her inside the simulation bubble, but Aelita uses Creativity to disperse it. The Lyoko Warriors try to protect Aelita, but William succeeds in throwing her into the Digital Sea. But suddenly, she is lifted from the sea by the real Franz Hopper, who appears as a floating blue bubble. William and the monsters are focused on eliminating Franz Hopper, but don't succeed. The group now realize why X.A.N.A. wants to throw Aelita into the Digital Sea. It knows it's the only way to get Hopper to expose himself.
X.A.N.A. launches a counterattack in their second trip to the Desert Replika in Hard Luck. At the military base where the supercomputer is located, X.A.N.A. activates a Tower to teleport Kankrelats into the real world to counter the intruders. In the facility, there lies an assembly line that makes motherboards and electronic implants. Ulrich manages to take out all of the Kankrelats and destroy the supercomputer by himself.X.A.N.A. attacks when Jeremie rides in an armed fighter jet in Guided Missile for winning a contest. X.A.N.A. possesses the jet to use its weapons to target and destroy the Factory and the Supercomputer with it. X.A.N.A. also forces the jet to crash to get rid of Jeremie too. Ulrich defeats William and sets Aelita free to stop the attack and launch a return in time.
In Kadic Bombshell, X.A.N.A. seizes an opportunity when a glitch is created in the Supercomputer because of Odd bringing someone into the lab. The glitch causes problems with virtualization. Aelita goes in to check for active Towers. X.A.N.A. sends monsters and William to the location to capture her. William tries to push her into the Digital Sea, but Odd saves her.
In Canine Conundrum, X.A.N.A. possesses Jeremie's robot dog in his room, and gives it the ability to replicate multiple copies of itself to attack the school. William and Tarantulas appear to guard the activated Tower on Lyoko. Aelita tricks William with a clone of herself, and gets to the Tower while he is distracted.X.A.N.A. fights the group on the next discovered Replika in A Space Oddity, which is a copy of Carthage and its supercomputer is on a newly built space station orbiting Earth. X.A.N.A.'s purpose for taking it over is to manufacture small, metallic spheres that grow spikes and burn through metal. Meanwhile, X.A.N.A. activates the Carthage copy's defense mechanism, which is charging a mass of energy that threatens to wipe out the Skid. Ulrich stops the mechanism by pressing the sector's key. X.A.N.A. uses the spheres to attack the ones who are on the space station. Odd and Yumi sabotage the supercomputer by breaking cooling pipes and short-circuiting it with water, completing their mission.
X.A.N.A. tries to cripple and destroy the Skidbladnir while at sea in Cousins Once Removed. While Jeremie leaves a program for the shields running on his room computer, Sissi and Herb mess with it and unknowingly endanger them in the middle of a battle. Jeremie puts up a firewall, after which X.A.N.A. possesses Sissi and Herb and takes over. It unleashes the Kalamar monster to attack the ship, while Herb breaks through the firewall and disables power to shields and weapons. Jeremie cuts power to the building, severing Herb's connection to the Supercomputer, and restoring their defenses. They destroy the monsters, and deactivate the Tower.
In Music to Soothe the Savage Beast, X.A.N.A. kidnaps Aelita again by possessing her show manager, and sends her to Lyoko, surrounded by monsters and William. It also possesses Milly and Tamiya to delay the group backstage at the concert. They save Aelita and deactivate the tower.
X.A.N.A. uses the Scyphozoa to control Aelita again in Wrong Exposure. It takes control of Principal Delmas to kidnap Aelita and take her to the Factory, and virtualize her alone on Lyoko, so the Scyphozoa can capture her mind. Its plan is to make the brainwashed Aelita walk into the Digital Sea by herself. Jeremie activates a program he made earlier to reboot everything inside of the virtual world and break her possession.
X.A.N.A. launches a standard attack in Bad Connection. It uses the school's cell phone antenna to spread a virus to everyone who answers their mobile, turning them into crazy, mindless slaves to be sent after people at the school. It uses monsters to guard the Tower, and plants a bug in the lab terminal to make it hard for Jeremie to execute commands. Aelita deactivates the Tower in time.
X.A.N.A. fights the heroes in the next Replika in Cold Sweat. This new Replika is an Ice Sector copy and its supercomputer is located in a lab in Siberia. In this facility, X.A.N.A. is storing brains in test tubes for an unknown purpose. William gets teleported to the base by X.A.N.A. to deal with the intruders. Aelita enters the Tower that commands his teleportation, but then she realizes that the Tower should contain the programs that X.A.N.A. uses to control William. She hacks into the Tower's data and transmits it to Jeremie. After deactivating the Tower, William comes back to the Ice Sector Replika. When he is dispatched by the group, X.A.N.A. suddenly draws on the power of the hundreds of Replikas that it controls to use its ultimate monster: the "Kolossus", a massive creature that resembles a fire elemental with a sword for a hand. It easily devirtualizes Aelita and Ulrich, and almost destroys the Skid.
In Down to Earth, X.A.N.A.'s plans for the world are revealed, and the group breaks William free from its control. Jeremie imagines a program for freeing William for good using the data gathered from the previous episode. They go back to the Ice Replika, in which they discover dozens of humanoid robots lined up like an army at the base. Jeremie realizes that its plan is to create armies of deadly robots to use to conquer the world. X.A.N.A. activates the robots stationed at the base, and sends them after Odd and Aelita. William goes into the Digital Sea, and comes back up with the Kolossus. Jeremie tries to immobilize the Kolossus, but breaks free and takes out Yumi. The Kolossus to stomps on Ulrich. Aelita is sent back to the Skid unconscious, and the Kolossus moves toward the ship. It seemed that X.A.N.A. had won, but William is devirtualized by Odd, freeing him from X.A.N.A.'s control and materializing him as his normal self. The Kolossus knocks the Skid into the Digital Sea in one blow, but Aelita was devirtualized in time. X.A.N.A. may no longer have William at its command, but this loss is inconsequential. It is now at the peak of its power with hundreds of Replikas at its disposal, and has manufactured an army to take over the world.X.A.N.A. has its last battle with the Lyoko Warriors in Fight to the Finish. Franz Hopper arranges a meeting on Lyoko for the group just when he finishes his multi-agent program for wiping out X.A.N.A. for good. Knowing they plan its demise, X.A.N.A. activates a Tower to possess William, proceeding to knock out Jeremie and try to unplug the Scanners. It also sends a strong force of monsters consisting of the Kolossus and a group of Mantas to destroy the Lyoko Warriors and Franz. Jeremie sends the Transport Orb for Odd and Aelita, since the program has to be activated from Carthage. Ulrich managed to defeat the Kolossus, but the giant's body falls on him, devirtualizing him. At the Celestial Dome, they try to run the program, but the energy requirements are too great. Mantas are sent to attack, and Franz Hopper appears and uses his remaining strength to power the program while bearing their lasers. Aelita launches the program, but to her horror, her father is destroyed right in front of her eyes. The program launches a powerful force from the Core of Lyoko which destroys the monsters and spreads to all the sectors of Lyoko, including the activated Tower. X.A.N.A.'s spectre is forced out of William, writhing in agony. The multi-agent program exits Lyoko's gate and covers the world network to destroy every one of X.A.N.A.'s Replikas in the net. X.A.N.A. screams in agony as its spectre form in the real world vaporizes out of existence as the Tower deactivates. Every trace of X.A.N.A. on the network has now been completely obliterated, ending the threat of X.A.N.A. forever.
Other ContinuityCortex. X.A.N.A. had injected its own source codes into the warriors in their last battle. It hides from the inventor of the Cortex, and sends spectres to Earth and take its source codes back, so it will become powerful enough to gain complete control of the entire world network.
X.A.N.A. resurfaces in the starting episode, X.A.N.A. 2.0. It makes strange computer bugs and short circuits occur at the school, which compels the group to reactivate Lyoko to see if their old enemy has returned. A Tower activates and monsters start attacking. On Earth, it creates a spectre with Jim's likeness, and it suddenly grabs Ulrich and he starts getting very weak and ill. They stop the attack.
In the episode Cortex, when the group reprograms the Skidbladnir and enter the Cortex, X.A.N.A. sends Krabs to stop them from accessing the core, but is met with failure.
In Spectromania, X.A.N.A. sends a kid spectre to steal source codes. It manages to touch Aelita, Yumi, and Odd before the Tower was deactivated, but this was a ruse to hide a second activated Tower whose signal was masked by the first, which generates another spectre in Ulrich's form. Odd gets to Lyoko and deactivates the second Tower. X.A.N.A. has gotten back about 70% of its source codes now.
In Rivalry, X.A.N.A. sends a spectre in the form of William and touched Yumi before it was discovered. On Lyoko, it sends three Tarantulas, making one of them invisible. Odd deactivates the Tower, but with its power at 75%, it is strong enough to relaunch another attack immediately. It disrupts the telephone network with a virus, rendering cellphones unusable. William and Ulrich cooperate together and deactivate the Tower.
X.A.N.A. launches a short attack in Suspicions. It creates a spectre in front of them. Aelita quickly deactivates the Tower, faced with no obstacles at all, before the spectre thought to steal their codes.
In Countdown, X.A.N.A. creates a polymorphic spectre to infiltrate the school and steal source codes. It touches Odd, and the event gives him speech problems as a side effect. On Lyoko, it creates a wall of Bloks to block their access to the Tower. The spectre planned to take all of their codes in one fell swoop when they all arrive at the lab. Odd defeats the Blok Wall and deactivates the Tower before the polymorph could touch them. X.A.N.A. has now recovered 80% of its strength.
In How to Fool X.A.N.A., X.A.N.A. sends a spectre with hypnotic abilities after Yumi. At the time, Jeremie injects false source codes inside of Ulrich that will destroy any spectre that tries to take them. However, X.A.N.A. discovers this plan thanks to a bug that it planted. Ulrich touches the spectre and implants it with the fake codes, which destroys it before it touches Yumi. This causes X.A.N.A. to lose some of its source codes, which are likely transferred back to Ulrich.
In Rendezvous, X.A.N.A. creates a spectre of Anthea Schaeffer, Aelita's mother, to take advantage of her feelings. On Lyoko, it uses two Towers that activate and deactivate in sequence to prevent the heroes from thwarting its scheme. It asks her to meet at the chapel through a message. They share a hug, in which the spectre touches her and steals her codes. Laura figures out the sequence and finds a window that allows Yumi and Odd to deactivate the Towers before Aelita loses all her codes. X.A.N.A. is at 80% power.
In Chaos at Kadic, X.A.N.A. activates a Tower from the Cortex to put a virus in the school's computer system, messing up test scores among other problems. They destroy the monsters, and Yumi deactivates the Tower.
In Friday the 13th, X.A.N.A. infects the Skidbladnir with a devastating virus. It activates a Tower in Carthage to cause lottery wins to happen all over the country as a diversion to buy time for the virus to be uploaded. Odd gets the infected ship out of Lyoko, and counters the virus with Laura and Aelita's help.X.A.N.A. seems to malfunction in Confusion. It keeps activating and deactivating Towers, causing spectres to emerge and disappear in moments, and monsters spontaneously disintegrate. In the Cortex, an army of Krabs and Tarantulas fight against Tyron's ninjas in the core, and attack the Lyoko Warriors as soon as they arrive. It is revealed that a security update made by Tyron on his supercomputer was the cause of its malfunctions, which it destroyed in the battle. This proves that both X.A.N.A. and Tyron act independently of each other, and he is completely unaware of its presence inside of his supercomputer.
In The Codeless, X.A.N.A. sends a spectre in the form of a football player which goes after Odd and steals the last of his source codes. It is now up to 85% power and activates another Tower soon after, sending a spectre with the same appearance as the last one. Yumi and William go after the Tower, but they are confronted by a virtual clone of William created by X.A.N.A., who plays on his doubts about his place on the team. William overcomes his feelings and turns on the clone, allowing Yumi to deactivate the Tower.
The group complete their virus to inject into the Cortex in Obstinacy. X.A.N.A. sends monsters to stop them, including Mantas that can now operate in the Digital Sea. When Aelita sees her mother in Tyron's lab through the webcam, they stop their plan.X.A.N.A.'s spectre gets caught in a trap by the group in The Trap. Jeremie plans to get source codes back from spectres, in which they create a situation were Yumi lures a spectre into a Scanner, and it works. Jeremie steals 4% of X.A.N.A.'s own codes through the spectre. It tries to escape, damaging the rest of the Scanners in the process. The spectre explodes inside and its residue gets virtualized as a living particle cloud. It puts Yumi and Ulrich into comas with its touch. Since the spectre was made to steal codes, it ignores the codeless Odd. With no codes in the virtual world, the spectre drags the unconscious Yumi to the Digital Sea. Jeremie transfers the source codes he has stolen to Odd, but they now compel the spectre to chase after him. Odd gets into the Tower, and enters the Lyoko code before it touches him. X.A.N.A. lost 4% power, and Odd is no longer codeless.
X.A.N.A. attacks using clones to confuse the group in False Pretenses. It sends a polymorphic spectre that shape-shifts into each of the Warriors to steal source codes, and creates perfect clones of them in the virtual world, confusing them. Jeremie and Laura launch a program to make the clones glow, allowing the real ones to devirtualize the fakes, and deactivate the Tower.In Mutiny, X.A.N.A. takes control of William again. Laura and William decide to act on their own to plant their virus immediately. They enter without much trouble, but he is then surrounded by Krabs. The Scyphozoa appears and implants its tentacles into his body, turning him into X.A.N.A.'s pawn once again. X.A.N.A. has the Scyphozoa hold him in its grasp the entire time, trying to steal their virus when it gotten uploaded into himself. The possessed William commands an army of Krabs and fights the group. Ulrich distracts him long enough for his tentacles to be cut, turning him back to normal.
In Jeremy's Blues, X.A.N.A. sets a clever trap for the group. Jeremie sends Ulrich and Odd in the Skid to investigate a data packet sent by an unknown source in the Digital Sea. Then, the ship gets caught in a trap. X.A.N.A. sends five Sharks to destroy the ship and the trap damages the holoweb, leaving them helpless. Aelita gets the two back to Earth, but the Sharks destroy the Skid. This incident has left both the holomap and the Superscan badly damaged. X.A.N.A. attacks with a spectre in Mrs. Hertz's appearance and sends Kankrelats that duplicate to hold back William and Yumi. The spectre gets some of Aelita's source codes. Jeremie quickly fixes the holomap, and they deactivate the Tower. X.A.N.A. is at 92% power now.
X.A.N.A. uses another spectre for a particularly offensive attack in Massacre. It sends a spectre in the form of Mr. Rouiller, while Yumi and Aelita are on a mission inside of the Cortex. The spectre steals Odd's codes. X.A.N.A. has eight Bloks guard the Tower, and Megatanks and Krabs attack Aelita and Yumi. The spectre steals Ulrich's codes also. Aelita escapes and arrives on Lyoko to take out the Bloks. Aelita deactivates the Tower before the spectre takes Yumi's codes. X.A.N.A. has rendered Ulrich and Odd codeless, and is up to 95% full power.In the final episode, Ultimate Mission, the Lyoko Warriors are forced to implant their virus immediately which would wipe out Tyron's supercomputer, and X.A.N.A. with it. During their first attempt, X.A.N.A.'s current power level allowed its Mantas to destroy the Megapod and the whole group in mere moments, forcing them to wait twelve more hours to try again. They suffer interference from Tyron in the real world, but they succeed in entering the core. Tyron shuts down his supercomputer to avoid losing all his data as they planted the virus. Unless Tyron finds an antivirus, X.A.N.A. will be rendered eternally frozen as long as the Cortex stays turned off. If Lyoko stays active, it will still have a way of escaping, so the group shuts down their own supercomputer, but will remain on their guard if it turns out X.A.N.A. survived again.
In this alternate continuity, the events of the first four seasons are severely streamlined as the first book indicates. While the events of the prequel and the first season are followed relatively the same as before, the climax of the rest of the series is compressed into one event. Franz Hopper reveals himself to the group before any equivalent of The Key occurs. He informs the group how to destroy X.A.N.A., by launching the multi-agent program into the Core of Lyoko. Hopper sacrifices himself to provide the energy needed, while at the same time restoring Aelita's memories and informing the group about her mother.
As for X.A.N.A., the entity is purged and ejected from Lyoko, having lost access to its core functions and left to drift in the network without its memories. Over the course of several months however, X.A.N.A. begins to gain strength back, and searches for a human vessel in lieu of a virtual world. Ultimately, it looks for a vessel that it can use to infiltrate Kadic without suspicion, so as to kill the Lyoko Warriors.
X.A.N.A. is a dark, powerful, and highly intelligent program that is capable of advanced calculations and programming skills. It controls Lyoko's systems, using the Supercomputer to affect the real world through manipulation of quantum energies. Its capabilities are listed below:
X.A.N.A. is connected to Lyoko from inside of the Carthage sector. It keeps a hidden presence in the virtual systems and controls Lyoko's functions from there. It was originally bound to the Supercomputer, but gained full system access with the newly acquired Keys to Lyoko, allowing it to escape its confines and into the worldwide web.towers. They allow it to interact with the real world, usually through electrical networks, but can also send materialized creatures, use implanted objects, or affect vulnerable people with an active tower. It can also take control of unprotected towers used by others, and perform advanced computing tasks with many in conjunction. Its own operations can only be countered by deactivating them.
Its access to the real world is done through transmission of energy pulses throughout the networks, allowing it to hack and possess any electronics, influence objects, project electrical energy, ultrasound, or magnetism from outlets, or spread viruses that can affect people. X.A.N.A. can also generate spectres from outlets, which are dark, ghostly creatures made from quantum digital energy that serve as physical extensions and can directly interact with the world.Its spectres can possess objects like a virus, modifying their properties and using them to launch its attacks, such as outside devices, natural elements, plants, animals, or entire locations. X.A.N.A. later gains the power to control humans, aside from the Lyoko Warriors who are immune to possession, and pixelize their matter to give them spectral bodies, increased physical abilities, electromagnetic energy manipulation, control over devices, and other supernatural powers. When their towers deactivate, the possessed objects return to normal, and living beings have no memory of being controlled.
X.A.N.A. can also generate polymorphic spectres. They are ghosts that can imitate appearances in addition to having pixelated abilities, making them more ideal for infiltration. It can release spectres that are programmed with set forms, or polymorphs that can change form at will. They disappear from reality when their towers deactivate. If a spectre is virtualized to Lyoko, it doesn't need a tower to exist in the real world anymore and can imitate other warriors, complete with their abilities and weapons as well.lasers, and each type has special attacks. It is capable of sending hordes of them, but only virtualizes a few at a time to save computer resources. As X.A.N.A. evolves, it can improve them, create new types, and be able to use some in special sectors.
X.A.N.A. sends monsters like the Kankrelats, Bloks, Hornets, Krabs, Megatanks, Tarantulas, and uses Creepers and Mantas in Carthage. It has also created the Scyphozoa, a powerful monster made to steal data and life energy from any virtual object or person that it catches with its tentacles, or implant viruses to control Lyoko Warriors in the virtual world.
X.A.N.A. is also a programmer and can use system functions, except the programs inside of the restricted access area. It can influence the sectors by altering parts of the landscape, unleashing virtual weather, creating illusions, rendering objects invisible, or generating portals. It can imprison warriors inside Guardians or Simulation Bubbles, launch programs through monsters, plant minor viruses and bugs, materialize or teleport minions to Earth, or send electronic messages. X.A.N.A. can also capture unprotected warriors and modify them to its will, even program special abilities, equipment, and vehicles for them to suit its needs.
After X.A.N.A. escaped from the Supercomputer, it can explore other systems in the world information network that lies beyond the Digital Sea. Inside of the underwater environment, X.A.N.A. sends monsters like Kongres, Sharks, and the Kalamar against its enemies, and can program traps like network firewalls.army of robots to invade and conquer the world. It counters intruders by activating their towers to control automated machines, use possessed humans, or teleport real monsters or warriors to fight them in the real world.
X.A.N.A. is capable of drawing the computing power of every Replika it controls in the world network to create its most powerful monster, a near-indestructible, fiery giant named the "Kolossus," which is the ultimate weapon to use against its enemies in any of the virtual worlds.
- X.A.N.A. was voiced by David Gasman in Ghost Channel, in the American version of Code Lyoko, the same actor who also voices Herb, Jim, and William.
- According to YTV's Vortex block's host Paula (Code Lyoko was a show on this block and during commercial breaks Paula would often share bits of trivia), X.A.N.A. was once a good computer program until an evil virus corrupted it. Interestingly, she said this piece of information in the middle of season one, before season two even aired. No evidence was stated to prove this fact, as it implies that it was Franz Hopper's abuse of the return in time program that made X.A.N.A. evil, not a virus. However, the novel series states that it really was a virus that corrupted it in the end.
- X.A.N.A.'s name was derived from Xanadu, the virtual world in Garage Kids.
- Since X.A.N.A. is basically a computer program, it is supposed to be genderless, neither male or female. However, everyone except Franz Hopper constantly addresses X.A.N.A. by male pronouns (he, him, his, etc.) in the main series. This may be due to all nouns having genders in French, the show's original language. In Code Lyoko Evolution, X.A.N.A. is rightfully called an "it" in the series.
|Jeremie Belpois | Aelita Schaeffer | Odd Della Robbia | Yumi Ishiyama | Ulrich Stern | William Dunbar|
|Sissi | Jim Morales | Suzanne Hertz | Anthea Schaeffer | Mr. Delmas | Laura Gauthier | Franz Hopper|
|Kiwi | Herb Pichon | Nicholas Poliakoff | Amelia "Milly" Solovieff | Tamiya Diop | Hiroki Ishiyama | Johnny | Takeo and Akiko Ishiyama|
|X.A.N.A. | Monsters|
|Professor Tyron | Ninjas | X.A.N.A. William|
|Jean-Baptiste Pujol | Theo Gauthier | Emily LeDuc | Taelia | Samantha Knight | Samantha Suarez | Heidi Klinger | Mathias Burrel | Magali de Vasseur | Claire Girard | Brynja Heringsdötir | Patrick Belpois | Romain Le Goff|
|X.A.N.A. Aelita | X.A.N.A. Odd | X.A.N.A. Yumi | X.A.N.A. Ulrich | X.A.N.A. Franz Hopper | X.A.N.A. Anthea Schaeffer | Jeremie Clone | Aelita Clone | William Clone | Subdigitals|
|Kankrelats | Hornet | Blok | Krab | Megatank | Creeper | Manta | Black Manta | Guardian | Tarantula | Scyphozoa | Kolossus|
|Spectre | Polymorphic Clone|
|Kongre | Shark | Kalamar|
|Video games only|
|Cyberhopper | Exploding Roachsters | Scorpion | Insekt | Dark Monster | Volcanoid | Ubertank | Omegatank | Mountain Bug | Insekt Lord | Ice Spider | Desert Driller | Magma Worm|