Author's Note: I do not own any part of Code: Lyoko, the original characters, or anything else. The only things within that I claim as my own are the created characters Aurora and Spire Xion, and Treg Zorl.

Author's Note 2: The fourth part takes place a mere days after "Xion is XANA". Treg Zorl has begun his assignment, but to what is it?

Author's Note 3: This fic focuses mainly on Treg, instead of the split Aurora/Spire in my past 3 fics.

XANA's Infiltration

Treg sits at his computer, deep within the Factory. He had been a student at the nearby Cadic Junior High, but graduated a few years ago. During his stay, he found the Factory and the deepset computer of the Factory's founder, Astra Xion. He had read Astra's notes on the hacker-virus. Treg's own grandfather had been a part of the assignment, and was in fact one of the three killed by XANA. He had recieved summons from XANA a few months previous, when he had found out about Astra's great-granddaughter's transcript to the school. Treg still could not believe that XANA had created a fifth Region within Lyoko. And wanted HIM to make the monsters that would guard the five towers within the region. Treg's assignment had progressed well, and he added the Dragon Guardians, Harpies, and Cannons to XANA's monster list. Treg knew about XANA's recent devitrualization of it's monsters into the real world, and locked the code for his monsters within many thousands of passwords, more than enough to keep XANA out of them. Nothing as dangerous as the Dragon Guardians should enter the real world...

Treg woke on the third morning after his return to France. XANA had him tailing the Xion children for the past two days, and today he was to reveal XANA's new Region to those that foiled XANA time and time again. "Alone, as in the past. Will I ever be used to it?" Treg asks himself. His parents had been killed by XANA, and this information he had kept locked deep within, hidden from XANA, along with his great hatred of the supercomputer. Treg stands and streaches, discovering a sore in his back that had developed from the chair near two newly created scanners. XANA had the robots in his Factory working while the children that were against him were away. XANA planned to send Treg to the Shadow Region to await those from the real world.

Treg stands from the desert ground, sensing that three from the real world had materialized in Lyoko. "So, you finally are here." he says, hearing them drop.

"Who are you?" one asks, he wears a sword at his side.

"I am Treg, the Soldier of XANA." Treg answers.

"One of XANA's." The one with the cat-tail says. The third, a girl armed with fans, throws her weapon at Treg. He catches it.

"Do not try to attack me. I could easily destroy each of you three from here. The Tower that has been activated is not hear. My signal is what your friend locked onto." Treg explains, and he hears another thud behind him. "Another? Ahh, his precious 'One and Only'." Treg turns to see the same girl that had been in the theatre, one of the Xion brats.

"What?" she asks, stunned.

"Too bad you four came here for nothing. The Tower XANA has activated is not here. Neither is Aelita, your little friend. Both are within the Shadow Region." Treg draws a sword and cuts a deep rift into the plateau. "If you ever wish to see your friend, you'll come with me to the Shadow Region. Hope you kids aren't afraid of the dark."

The trip had been rougher than Treg'd exspected. If he'd calculated correctly, then the Guardian would be within spitting distance, and once his eyes adjust into the Shadow Veil, he speaks. "And it is." He walks over to the Guardian and draws his sword across it, destroying it and releasing the captive Aelita. "Your friends are here." he says, listening to the four entering by the rift he'd created. Aelita backs away from Treg, who turns to watch the four from Earth stumble within the darkness. "If you can make fire, then you can see." he says. "But you might not like what is here. Especially those that fly overhead." Treg steps over and grabs Aelita's arm, pulling her to her feet. "You are nothing to me, except tools for my revenge. Cannon!" He yells and something rolls over to him. "Take this one to the tower. No doubt XANA's causing mischief in the real world." Treg lays Aelita across the Cannon and it rolls off. "The reason you are here is because of XANA. He has caused much pain, hasn't he?" Treg asks, finding the sight of the stumbling people less amusing.

"How would you know?" Aurora stumbles closer to Treg's voice.

"Because he did the same to me. But know, you will see me again. The past is upon us."

Treg awakes again on the third morning. He knew XANA wasn't paying attention to his conversation with those that hated him. XANA only sent the monsters and never payed any attention. Treg leans forward and rubs his eyes. "Now what do I do?" He says to the empty void. After a few minutes, he looks up, a great gleam in his eyes.

"It's been a while, Treg." The principal says. Treg nods and adjusts hs dark glasses. He knew that the four from Lyoko went here.

"Yes it has. Three years I think." Treg agrees.

"What brings you back here?"

"Severe boredom, for one. And wanted to see what teachers were still left." Treg's left arm flexes from under his dark trenchcoat.

"Just don't get into any trouble with Jim on your first day back." The principal reffers to the gym teacher that wasn't more than ten years older than the 18-year-old kid.

"Don't worry. I'll stay away from him like when I was here." he leaves the room, letting the door slam on the way.

Treg looks up and down the empty halls, remembering full well the havock that would be reaked in the next five minutes. He stands outside Mrs. Hertz's class, wanting to stop by his favorite teacher. As soon as he opens the door, the bell rings. His eyes scan the room, immediately spotting Odd, Ulrich, and Aurora. As they approach the door, Treg blocks their way. "You three, I want to talk to you in a minute." He says and moves to Mrs Hertz. "Hello, Teach." Mrs Hertz looks up.

"Do I know you?" she asks.

"How could you forget me? The half-done assignments, along with the perfect tests. How often do students come through like that?"

"Treg Zorl? Is it really you?" Mrs Hertz looks at him closer. "It is! Treg, what have you been doing with yourself?" she asks.

"Not really that much. Been working with computers in Japan and the States. Took me long enough to get used to Japan. Even longer for the States." Treg embraces his teacher in a hug.

"Computer work in the States? Really?" Treg nods.

"Unfortunately, I can only stay here for a few days, and I'll need to say hi to my other teachers. I'll try to come by when I leave." Treg Zorl leaves the science room for the last time.

"Good, you waited." Treg closes the door and connects eyes with the three students and one that he hadn't stopped. "You do not recognize me, but I did promise that you'd see me again. As for you, 'One and Only'." Treg looks right at Aurora and pulls off his glasses, revealing his XANA-smbol shaped eyes.

"You were in the theatre!" Aurora says.

"You told Mrs Hertz you were Treg." Odd looks supiciously at the older man.

"Yes. I am the same Treg that lead you to the Shadow Region. But there is something that you need to know, but I'd rather tell it to all four of you that were on Lyoko. Meet me in the Factory during lunch time." Treg leaves the building and crosses to the soccer field.

"About time." Treg rises from his seat in the elevator. "And you brought him too." he looks to the boy that he had not stopped. "One thing that you must know: XANA is here to destroy. He will not do anything else until his secret is fully safe."

"What are you talking about?" Jeremy, the one Treg had not stopped, asks.

"His goal is to first kill the five of you, then the other Xion kid. After that, it's me then the world. Nothing will stand in his way once the seven of us are gone. Wich is why you must let me handle things on Lyoko for a while."

"Why should we believe you?" Yumi asks. She was the only one that had not seen him in the halls.

"Because I am the only one XANA trusts. And if I do succeed, then I will give you XANA's greatest treasure. His Omega Scanners."