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X.A.N.A. William is a character when William is possessed by X.A.N.A.. In the show, X.A.N.A.-fied characters were simply referred to by character names. However, the "X.A.N.A." prefix is customary among fans. X.A.N.A. William is a secondary antagonist in Season 4. He made his first appearance in Final Round.


Season Three

William falls even deeper in X.A.N.A.'s power after destroying Lyoko.

X.A.N.A. William is created in Final Round, where William becomes too cocky and ends up being possessed by the Scyphozoa. X.A.N.A. William is released by the Scyphozoa and then dropped on the ground, having his mind and body taken over by X.A.N.A. and he turns to Aelita to overwhelm her with his Zweihänder to block every attack and let out a wide, energy slash at, which devirtualizes her in a single hit, once done, he shouts in glory of his kill. X.A.N.A. William heads over to the Heart of Lyoko to prepare to destroy it, and the virtual world as well. By being distracted by his old team, X.A.N.A. William gets ready to snuff them out, he first devirtualizes Odd with the same slash, using more precise accuracy and second sneaks up when Ulrich is left distracted and stabs him, and he lastly reacts faster, sneak attacking Yumi with a Super Sprint ability, devirtualizing her as well and hearing her saying she knew that he shouldn't have gone with the group. With the warriors out of the way, X.A.N.A. William takes his chance and uses his Zweihänder to destroy the core of Lyoko, the digital world is gone and with all the last remaining energy, it goes into William and with a special process, his biological and avatar code is altered, thus having his body permanently marked with X.A.N.A.. Also, in the loss of hope, the team gets a message from Franz Hopper, who is currently hiding in the internet and recieves a method of build codes, so they may recreate Lyoko.

Season Four

X.A.N.A. William in William Returns.

X.A.N.A. William appears in the episode William Returns, where X.A.N.A. William steps out of the Scanner and disguises himself as the real William where he claims that he doesn't recall anything about being X.A.N.A.'s slave or how he had escaped the Digital Sea. When Sissi questions Aelita's personal life for a "scoop", the false William comes in to get her out. As soon as he is alone with her, William reveals that he is still controlled by X.A.N.A. and makes her his "prisoner". When fully shown as X.A.N.A. with the dead stare and eyes, he gets an unconscious Aelita ready to go into Lyoko, and makes sure she is with him at all times, using his Super Smoke ability to keep her like it. When he succeeds and has her in his grasp, he makes it to the Celestial Dome and calls for a Black Manta to get himself and Aelita to the outer side of Sector Five. X.A.N.A. William also takes precaution and keeps his boot on her, so she can't escape.

In a ride to Aelita's death, X.A.N.A. William is pursued by Ulrich and Yumi with their vehicles and the monster releases mines that do the same action back at them. Ulrich is devirtualized by the Black Manta's flying mines and leaves out Yumi to deal with William, before Odd arrives from his Disco Training. X.A.N.A. William and Yumi make their way outside Sector Five, only to have the incomplete Desert Sector showing only the Digital Sea in the area. Once they are outside, X.A.N.A. William counterattacks Yumi more clever with an energy wave from his sword, having Yumi lose balance and fall off her Overwing. Odd's Laser Arrows save Yumi and now gets rid of the Manta, forcing X.A.N.A. William to throw Aelita off the manta and into the sea. Aelita is quickly rescued by Odd on his Overboard, however. Odd then destroys X.A.N.A. William's manta causing him to have no choice but to dive into the Digital Sea.

Due to the program failing to prevent its enemies from succeeding, X.A.N.A. William is the emergency attack and plan B for it during Season 4. It commands him to take out the Lyoko Warriors and dominate the world, which it works out. In Double Take, William has shown to eventually flucuate control over the towers, while calmly observing the tower turning red which he struggled to keep it that way.

In The Lake, as X.A.N.A. William is about to devirtualize Yumi, the former is stopped from doing so when Yumi reminds him that he was a Lyoko Warrior, causing X.A.N.A. William to drop his sword and have an inner conflict as his memories of joining the team and telling them to promise to keep the secret resurface. Unfortunately, X.A.N.A. manages to regain his control of William, causing him to attack Yumi again when she tries to help him, and almost succeeds in devirtualizing her at the edge of the platform, but is immediately stopped when Aelita shoots an energy field at him, making him fall into the Digital Sea. Yumi then says to Aelita that real William has returned for a second and Aelita assures her they will bring him back someday.

In A Lack of Goodwill, X.A.N.A. William is materialized onto Earth by X.A.N.A. to destroy the Supercomputer, but is stopped by Jeremie, who attempts to attack him but gets injured in the struggle. William's clone then arrives at the scene with Milly and Tamiya and starts fighting the real William off, only to be eventually deleted by the latter, who did so by manually deactivating the clone's tower. X.A.N.A. William then attempts to destroy the supercomputer again by tampering with its cooling system, thus overheating it. When the rest of the Lyoko Warriors arrive at the lab, X.A.N.A. William quickly revirtualizes himself back to Lyoko instead of facing them. However, his attempts to destroy the supercomputer prove futile, as Aelita is able to restore its cooling system before it was too late.

In Cold Sweat, Aelita discovers data that can be used to free William from the tower in the Ice Replika that X.A.N.A. used to translate him onto its Replika's facility, as it gives access to the programs X.A.N.A. uses to keep William under his control. In the next episode, Down to Earth, the group manages to free William from X.A.N.A.'s control, though at the cost of the Skidbladnir.

However, due to spending most of his time in the virtual world under X.A.N.A.'s control, as opposed to using the scanners constantly as the other Lyoko Warriors did, X.A.N.A. is able to possess William once again in Fight to the Finish, whereupon he battles Yumi, and later Ulrich, in the Factory. When the X.A.N.A. Destruction Program is released, X.A.N.A. William emits a large amount of black smoke from his body, to signify X.A.N.A.'s apparent demise.

Season Five (Code Lyoko Evolution)

In Mutiny, Laura sends William to the Cortex alone to try and insert a virus that would destroy X.A.N.A. (though in the process, they would lose contact with Aelita's mother). This wasn't a legal mission. While on the Cortex, William accidentally runs into the Scyphozoa. He tries to escape by devirtualizing himself, but he is captured and possessed again before he has the chance. However, the Scyphozoa has not managed a full possession, William is being held up above the ground by its tentacles, surrounded by a black aura. He raises his hand and a digital sound comes from his mouth, commanding the Krabs.

Aelita, Ulrich, and Yumi can't do anything against the massive army of monsters, and they take shelter behind the Megapod. They decide that talking to William and trying to wake him up is the best course of action, acting as a distraction so someone else can get closer to the Scyphozoa and sever the mental connection between it and William. Ulrich fights William, constantly goading him to try and remind him of their romantic rivalry and his life on Earth. It seems to work, as William slowly becomes more and more human-like again, eventually allowing the Scyphozoa to be cut off. His black aura disappears and William returns to normal, thanking the others for saving him from X.A.N.A.'s clutches again.


Season Three

Season Four

Season Five

Video Games


In the first series, X.A.N.A. William first appeared as the average possessed avatar which consists of the base form with an eye of X.A.N.A.. Next, when the program has enough power of Lyoko, it merges with its host and takes on a new avatar that can vary from creature-to-creature. William's new avatar was then tranformed into a deeply sinister form which consists of a black and red scheme, a tight collar, a fingerless glove on his right arm and a spike bracelet around the left, a double-strap buckle near one of his thighs and a circuit decorated on the other, and has an eye of X.A.N.A. on his forehead and one on his chest that glows.

In the reboot series, X.A.N.A. William had the exact same avatar but it took on a green and black color scheme.

X.A.N.A. can also control William's physical forms when he is in different planes of existence.


William has been transformed drastically from a Lyoko Warrior to a X.A.N.A. Warrior due to being under the program's dominance via possession. Additionally, with X.A.N.A. having full access to his memories and physical form, William has been given a directive of doing what his master plans and does, and with X.A.N.A. being malevolent around anybody, William is not able to control his actions. This detail is confirmed in The Lake, where for a few moments, Yumi triggered a memory that brought the real William out for a few seconds, which further proved that the program was doing everything in that time. Also with X.A.N.A. having William's body as its own, it has never responded to the name of its host which makes this a situation of the Lyoko Warriors essentially fighting an incarnation X.A.N.A. more than William.. In Code Lyoko Evolution, the idea that X.A.N.A. is in control is proven when William was surrounded by Krabs and captured by the Scyphozoa, saying There is no one with that name here when Ulrich failed to get through to William.

When in combat, X.A.N.A. William, is naturally smarter than William himself due to X.A.N.A.'s influence. He is more precise with improved swordsmanship and is more tactical when it is needed the most, and he can use the actions of William to fool unaware enemies. However, some aspects of William's prior poor strategy are still evident, as X.A.N.A. William generally prefers to use brute force with his abilities.

Powers and Abilities

Initially, X.A.N.A. William displayed many of the original William's potential as a Lyoko Warrior. However, since the program X.A.N.A. had complete access to his form, it now demonstrated more accurate forms of skill over the Zweihänder and incredible mastery over all physical power, such as falling from dangerous heights and leaving a crater in the presence, without injury. Additional exposure to the program lurking inside William bestowed him access to new abilities, a darker avatar and the power to dominate the human world solo, but X.A.N.A. overtakes his body to control these abilities. In Evolution, William naturally possesses nearly every ability of X.A.N.A. William but with some limitations.


  • Super Smoke: An ability that rivals Ulrich's Super Sprint as his body turns into a shadow-like form to travel after enemies and occasionally affect a victim under its control, which is much like X.A.N.A. who now makes up part of William's body. This is primarily used when he is outnumbered in human form.
  • Second View: An ability that uses Xana's own visual perspective to detect escaping enemies.
  • Levitation: An ability that gives William the weightless effects of a spectre. He can use this when his Zweihänder is facing down or channeling enough concentration. 
  • Tower Control: A hardly used Ability that activates Towers with a specialized code for the access X.A.N.A. can have, much like Aelita's natural control over Tower's. X.A.N.A. also can use this for his Annex Program but can only be used through a human-based body, which it now has.
  • Monster Riding: An ability that gives him the ability to control his own monsters anytime he needs it. Thanks to William being recognized as X.A.N.A. with looks and voice, this is easy and passive, unlike most means.


  • Black Manta - A unique Manta for William to ride on as a vehicle.
  • Rorkal - A virtual ship like a Nav Skid created for William, but he was given a black, independent one by X.A.N.A, who made it by using the data he had stolen from the Skidbladnir through the Scyphozoa in The Lake.


  • In European Portuguese, he was played by Quimbé.
  • In French, he was played by Mathieu Moreau.
  • The term "X.A.N.A. warrior" sums up this version of William perfectly, as the real William is no longer able to fight alongside his allies as a Lyoko Warrior.


>> More images of X.A.N.A. William in Season 3

>> More images of X.A.N.A. William in Season 4


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