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 first appeared 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 in terror with his Zweihänder to block every attack and let out a wide, Energy Slash at, which devirtualizes her and once done, he shouts in glory of his kill. X.A.N.A. William heads over to the Heart of Lyoko to prepare to peel it open, for the end of the virtual world. 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 un-guarded and stabs him, and he lastly reacts faster, sneak attacking Yumi with a Super Sprint ability, devirtualizing her as well and having her doubt in her mind that he shouldn't have gone with the ground. 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 lost of hope, the team gets a message from Franz Hopper, who is currently hiding in the internet, so they may re-create Lyoko.

Season Four

William possessed

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 didn't recall 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 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 digital world showing 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 fluxuate control over the towers, while calmly observing the tower turning red which he struggled to keep it that way.

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 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


X.A.N.A. William appears as a unique model compared to other X.A.N.A.-fied victims (due to the process proceeded after the energy of Lyoko's essence merged to his body). In the digital world, his suit is black with many indigo-colored details with on his right arm, a long fingerless, biker's sleeve (symbolizing his dark and brute nature), and on the left consists of a spiked bracelet, he has a mark of the Eye Of X.A.N.A. on his chest (which glows a hazey orange color) and at his forehead is the eye in a purely white color. His left leg has a double buckle strap near his thigh and a long line going down the right. He has been seen radiating a black smog aura at times. However, in the human world (excluding moments seen with his avatar), he appears just the same as William but can possess an eye of X.A.N.A. once the true form in control is revealed.


In the first and second series, William is changed from being a Lyoko Warrior who promised to fight for his team and into a X.A.N.A. Warrior that does the opposite. By being brainwashed, William possesses every part of X.A.N.A.'s behavior and has enough intellect to decieve his team, and especially in situations with Aelita, who believes the real William has kidnapped her, when in reality X.A.N.A. tricks her by using William's ordinary self and voice against her. X.A.N.A. William has most of the time ditch his enemies, as soon as the plan fails (this includes the moment the program gave up during the meteor shower as he leaped into the Digital Sea at the exact moment). Also, just like the same program, William has shown to want Franz Hopper far away from his daughter (which the real William also had no intention what so ever in Franz Hopper) and as its creator plunged into the Digital Sea, he responded with a "Noooo!". There are moments the real William will regain control over his body, but the program eventually proves too much for him, as seen when Yumi tries to remind him he fights for her team.

Aside from personality traits, X.A.N.A. William has shown to be more smarter than William himself in battle, such as able to sneak up around his foes and learn to adapt in the battlefield, he commands his monsters to go do independant attacks where they unfortunately will fail without their master, he even possesses a large range of plans to deflect or use the team's predictable attacks against them and will know how to manipulate them if he gets the chance. He will usually stick with his monster's and sword in battle, but sometimes he will be bested by each member.

Powers and abilities

X.A.N.A. William has all the same powers as William does, and modified by X.A.N.A. He wields a darker version of the Zweihänder, which X.A.N.A. made much lighter as evident by the fact that X.A.N.A. William can freely swing the sword or hold it with one hand. The sword can also fire deadly energy waves when it is swung. 


  • Super Smoke: An ability much like Ulrich's Super Sprint, but instead of simply running at speed, X.A.N.A. William becomes smoke to pass away from virtual objects, monsters, and warriors. He can project black smoke onto others to suspend them in a paralyzed state. Super Smoke is known to be much faster than Ulrich's Super Sprint.
  • Second View: The ability to see much farther away in the virtual world.
  • Levitation: An ability that allows him to levitate by holding his Zweihänder by both hands and pointing downward. 
  • Tower Control: Ability to activate Towers for X.A.N.A. He can exert influence over protected Towers until they succumb with time, and access their interfaces from inside the Towers. This like Aelita's own Tower control abilities, and it is possible X.A.N.A. allowed him to use a version of the Annex Program.
  • Monster Riding: Ability to ride monsters on Lyoko. He can also command them to be lead against X.A.N.A.'s enemies.


  • 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.



>> 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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