Author's Note: I do not own Code Lyoko or anything affiliated with it. It I did, I could die happily. As it is, the rights to it belong solely to their respective owners.

Summary: After the incident with the Yumi clone, Jeremy checked to see if the supercomputer already had a similar program. What he found was something else, a program called 'Defender'. Curious, he activated it… and awakened a being claiming to be Aelita's older brother.

Code Lyoko: Defender

Chapter 1: A New Program

Male Dormitory, Kadic Academy, France

'Looks like it's going to be another all-nighter for me.'

That was the thought of one Jeremy Belpois as he looked at the clock on the lower right corner of his monitor. Said clock read it as being 3:26 AM, long past the time when any sane person would go to sleep. Moreover, he knew that if he tried going to sleep now, he'd just end up falling back asleep in class. Better to just power through the night and keep working.

At least one person disagreed though, as evidence by a window popping up on one of his screens, showing a familiar face. A girl with pink hair and bright green eyes, with pointed ears and one earring on her left ear. Although the window only showed her face, she also wore a pink and white mini skirt and top, over beige trousers and a long shirt.

This girl, Aelita, had to restrain a sigh at seeing the blonde genius working all night again. "Jeremy, you know it's not the end of the world if I'm here for a little longer. You should get some sleep," she advised.

Jeremy grunted and shook his head, glancing over at her. "I know that. But now X.A.N.A has proven that materializing virtual being is possible, I know I can figure out how to do the same for you. How can I sleep knowing that?" he responded. Then, after a moment, he cracked a smile. "Besides, it's not as if I find it bothersome. I like programming, just as I like talking with you."

Not for the first time, Aelita was touched by the amount of compassion in the statement. Jeremy was, and still is, the first human being she could recall interacting with. For him to be willing to risk his own health for her sake—even though she didn't need it, she knew sleep was important to being in the 'real world'—and even find joy it… well, if she had the ability to, she'd have blushed then.

"Jeremy… thank you," she said sincerely, and smiled when his own expression brightened. But let it not be said that she wasn't stubborn at time, as she added on "But even so, If you go too long without resting, you'll end up burning yourself out. And how can you get anything done then?"

There was a moment of silence as the blonde mulled over her words. Eventually, he sighed and nodded. "You're right. Okay, just let me check one other thing and then I'll get a few hours of shut-eye," he said.

Aelita nodded, before tilting her head. "I hope you don't me asking, but what are you looking for?"

Jeremy shrugged. "Just an idea I had. Since X.A.N.A. is a sentient program that lives in the supercomputer, it isn't capable of doing anything the supercomputer itself can't. And that includes creating other sentient programs, like the clone of Yumi that we faced. So I decided to check if the supercomputer has something like that, or if it was something X.A.N.A came up with on its own," he explained.

Aelita blinked. "Do you think it's possible, then, that there are other AIs in the supercomputer besides X.A.N.A. and myself?" she questioned.

"No idea. But that's what I'm checking to—huh?" he said, before stopping.

"What is it?"

"I think I did find something…" he said, leaning in. "Some sort of program, titled 'Defender'. From what I can see, it was supposed to be activated when the supercomputer was initially turned on, but wasn't. Strange…"

Aelita hummed in thought. "If it has a name like 'Defender', then I don't suppose it can be too bad. At least, depending on what it's defending. Can you try and start it?"

"Not from here, no. It looks like I'll need to actually to The Factory and run it there in order for it work. I'll see if I can't stop by tomorrow," he said.

"I understand. Sweet dreams, Jeremy," Aelita said, before the window showing her closed.

Jeremy smiled and shut off his computer. If this thing turned out to be a pre-made materialization program, they could have Aelita off Lyoko by tomorrow!

Jeremy told the others about his find the next day, but it seemed like testing the 'Defender' program would have to wait. Apparently, there was some big-name movie director that was in-town, and had wanted to make an announcement to the school. So the staff had put together a presentation, which included one of the previous movies done by said director, for the student to watch.

The group's response to the film, a mixture of sci-fi and horror with a rampaging alien, was… divided to say the least. While Ulrich thought the film was fantastic, Jeremy considered it to be completely ridiculous. Odd liked the special effects, and Yumi considered it to be genuinely scary.

Once film was over, and the lights turned back on, Principal Delmas handed the mic over to the movie director, James Finson.

"Thank you for your time, sir. I'd like to also announce that I'm on town because I'm looking for a location to shoot my next film at. In fact, I was planning on choosing a nearby factory I had heard about that's been abandoned for several years," he told them.

While the other students were cheering, excited about the idea of having a movie shot in their own town, Jeremy's eyes widened. He didn't mean the factory they went to, did he?

Following his presentation, Finson handing out autographed photos to students. During that time, Jeremy and the others met a ways off from the table he was at. "Look, if this James Finson finds the supercomputer, we're in big trouble," Jeremy pointed out.

Yumi nodded. "I agree. So we have to find a way to convince him not to shoot there," she said.

"Okay, but how are we going to do that?" Odd asked.

From there ensured a chain of vents that, to an outside observer, would seem rather comedic. Sissi tried and ultimately failed to get a role in Finson's new film, while Ulrich came up with various stories about how the Factory was falling apart, haunted, infested with rats, and had been used to store radioactive waste from the nearby power plant.

None of these claims, unfortunately, were enough to dissuade Finson from shooting there. On the contrary, each story only served to make him more excited and further convinced he had found the perfect spot. At the very least, Ulrich had been able to get a position on set as a technical advisor, though it came at the cost of Sissi being given a film role as well.

Once the shooting had begun, however, it took less than a day for something to go wrong. That same evening, after Finch has shown them the fake alien that would appear in the movie, Ulrich managed to sneak down to the lower levels of the factory and use the super computer.

"Hey, Jeremy? It's me, Ulrich. Our phones were confiscated once we arrived on set. I'll do what I can, but it'll be hard to contact you," he said.

Before Jeremy could respond, they heard an all-too-familiar voice say "Well, well. What kind of place do we have here?" Ulrich jumped out of the seat and turned around. To his dismay, jumping off the same ladder he had used to get there, was Sissi.

"Uh… Sissi, listen. I can't really explain right now, but you can't tell anyone about this, or-" he began.

"Or what?" Sissi countered. "A big scary monster is going to try and eat my brain?" he said sarcastically.

In a moment of cosmically coincidental timing, a large glob of what looked like green goo fell onto her head. Sissi shouted in surprise, and they both looked up. There, standing in the rafters and hissing at them, was the same alien that Finch had shown them earlier in the day. And it was moving.

Sissi promptly screamed and would have started running, were she not frozen in fear. As it was, the alien dismissed her and spat a glob of saliva at Ulrich, who jumped out of the way and let it splatter all over the floor.

"Jeremy, we've got a big problem!" he shouted, hoping the mic on the headset could pick that up. Without waiting to see if it did, he grabbed Sissi and began running for the elevator. The alien roared and jumped down, landing on both feet without a scratch, and chased after them. The both sets of doors to the elevator closed just as it leaped towards them, causing the alien to crash against the door was a resounding thud.

As the elevator began rising up, both Ulrich and Sissi sighed in relief… until the floor started bulging. To make matters worse, the elevator abruptly came to a halt, leaving them trapped. "Oh, no!" Ulrich groaned, and began looking for a way out.

Thankfully, there was one, an exit on the roof of the elevator. The two of them quickly climbed out of it, and then through a grate located on the wall of the elevator shaft. The alien, while thin enough to fit through the first exit, was too large fit inside the grate, leaving it to roar angrily as they crawled away.

And so the chase went on for multiple hours, Ulrich using his knowledge of the factory's layout to evade the alien, even as it searched for them with a skill that was, quite literally, inhuman. They couldn't outrun it forever, though, and were eventually corned and pinned to a way with goo.

Around this time, the rest of the gang were able to slip past the sleeping guard and into the Factory as well. Using one of the other routes that didn't involve the elevator, they were able to avoid Finson and the rest of the movie staff. Yumi split off from the group to find Ulrich and Sissi while Odd and Jeremy would handle things on Lyoko.

Once he was in front of the computer, Jeremy put his headset on. "Aelita? Can you hear me?"

Inside Lyoko, within the Desert Sector, Aelita looked up at the sound of his voice. "Jeremy, thing's aren't looking good here. X.A.N.A has activated another tower," she told him.

He nodded. "Right. The scan show that it's in the Ice Sector," he told her. Then, after a moment's hesitation, he asked "With Ulrich missing and Yumi looking for him, it'll be just Odd helping you. Do you think this might be good time to try that Defender program I found?"

However, Aelita shook her head. "We can save it as a last resort, but without knowing what it does, it's too risky," she told him.

He nodded. "I agree. Alright, transfer Odd… scanner Odd… Virtualization!" he declared, hitting the key for the process to begin.

Lyoko

Odd opened his eyes and, with the practice of having done this many times before, executed a perfect three-point landing as he reached the ground. Clad once more in his signature purple cat suit—why did his digital self look this anyway?—he stood up and looked around.

The canner had dropped him onto a long bridge made of ice, with the Digital Sea located on either side. A ways ahead of him was Aelita, who began running closer the moment he arrived. "Nice place you got here, though a little cold for my taste," he said, grinning.

Aelita smiled at the bit of humor, made all the more apparent by the fact that, on Lyoko, the was no such thing as heat and cold. "Then let's run on our way to the tower, it'll warm up," she replied in turn, and the two began rushing along the bridge.

It was as they were nearing the end of it that they heard Jeremy come online again, stating "Odd, we've got trouble. There's a swarm of three Hornets coming in behind you, and three Krabs up ahead!"

Odd's eyes widened. "Six monsters for just me? That seems a little overkill, don't you think?!" he said.

"Maybe it's because of that program. X.A.N.A. must have not wanted you to find it," Aelita said.

Stopping his run, Odd spun around and began readying his Laser Arrows. "If that creep doesn't like whatever is, that's good enough for me. I say to fire it up!' he yelled, before using his increased again to leap of a nearby ice pillar and right in front of one of the Hornets. At such close range, it had no hope of dodging, and took a shot straight to the eye mark on its front.

The Hornet blew apart into fading pieces od data, while the other four scattered and met up at the other end of the bridge. On their next fly-by, one managed to get a revenge shot on him, hitting Odd straight in the chest for 20 life points.

In the real world, Yumi had managed to find and free Ulrich and Sissi, but then they were found by Finson, who thought that they had stolen the alien prop. This proved to be incorrect when said alien attacked them, pinning Finson and two of members o the staffs a window. However, that gave the others enough time to escape to another room, barricading it with tables, chairs and bookcases.

The alien growled and began ramming its shoulder against the door. However, any progress it was making was slow, which served only to further enrage it.

The three of them huddled as far away from the door as possible. Yumi, noticing that her phone was going off, answered. "Jeremy? Yeah, I found them, but X.A.N.A.'s taken possession of this monster, and it's coming for us!" she told him.

"Odd, the others are in a bad way! Hurry!" Jeremy told them.

Odd nodded and began running faster, both him and Aelita trying to outrun the Hornets. They succeeded, but only because the path ended in an ice tunnel they were able to slide down. Odd found the ride fun. Aelita? Not so much.

The tunnel ended in a drop onto another plateau of ice, though they were fortunately able to thankfully land on their feet. Unfortunately, the entire ride brought them much to the tower, were the Krabs that Jeremy had mentioned were waiting.

The moment they saw the two heroes, the three monsters began firing, going for the aggressive and marching forward.

Odd and Aelita were forced to dive for cover, hiding behind two ice pillars. "Uh, Jeremy? You gonna run that program? Cause if that will help us in any way, I could use it!" Odd called.

Jeremy hesitated, before nodding. "Alright, I hope I'm not going to regret this…" he said, before pulling up the program and typing to the command to activate. The screen returned a message saying 'Defender File: Activiating'.

And then… nothing.

"…Huh?" Jeremy said.

In Lyoko, Odd fired off three more arrows at the Hornets, who flew out of the same tunnle they had gone through. One arrow missed, but another hit dead-on, destroying the monster and leaving only one Hornet left. "Jeremy? I have only two arrows left. Did it work?" he asked.

"That's just it. I started the program like I was supposed to, everything went fine… and now there's nothing! It's not doing anything!" he told them.

Off resisted the urge to groan. Great, now they were stuck. The lone Hornet flew around for another un, and Odd was able to shoot it down, but now he was left with only one arrow. And, as luck would have it, that was the moment that the first Krab marched to where they were hiding, seeing one target on either side.

"Uh-oh. Aelita, run!" Odd called, before doing the same. The pinkette nodded and rushed out from behind her cover. Another of the Krabs immediately began firing on her, releasing a barrage of shots from its lower lenses. Only one managed to hit, striking her right in the left knee. Aelita faltered but kept running, reaching another block of ice to hide behind.

Odd, on he other hand, was playing a game of cat-and-mouse, using his speed and flexibility to repeatedly dodge both laser shots and attempts from one of the Krabs to impale him with its legs. The third Krab was staying back and only shooting, staying hear the tower.

Panting as he jumped over another laser, Odd said, "Alright, it's now or never!" Rushing forward, he side-stepped a regular shot from the Krab targeting him and, once close enough, he leaped into the air. "Take this!" he called, and fired his last arrow at the eye-mark on top of its shell.

In almost slow-motion, Odd watched as the Krab reached up, releasing another volley of smaller lasers… and one of them just so happened to hit his arrow. The two shows canceled each other out with a small burst of light, leaving the Krab unharmed. The Krab then reached forward , Odd's widened in horror as he fell… forwards… onto its legs

"Odd!/Odd!" Aelita and Jeremy both called.

Said teen slowly looking down at the limb impaling his chest. "Well… that's not good," he managed to rasp out, before breaking apart into pieces of data as he was devirtualized.

Now with the primary threat gone, the Krab turned in the direction of Aelita, walking closer.

"Aelita! Get out of there!" Jeremy yelled in terror, not noticing one of the side screens pop-up with a message saying 'Complete'. She nodded and was about to do so when the third, which had been hanging back up to that point, ran around to cut off her escape.

Aelita looked around in fear as the Krabs surrounded her. There nowhere to run, she couldn't trick the Krabs into hitting each other and—not for the first time—she lamented the fact that she had no weapons.

And so, with nothing else to do, she swallowed her sadness, and closed her eyes. In doing so, she missed the sight of something exiting from the Tower and begin running towards her. "Jeremy… it looks like I won't be able to see your world after all," she whispered.

"AELITA!" Jeremy screamed, but she ignored him. Standing up, she faced one of the Krabs, and waited for the inevtiable. The Krabs obliged, charging up their triple lasers. Each one would hit for 40 lift points worth of damage, and with three of them, there was no way she'd survive. The Eye of X.A.N.A appeared over their lenses, each reared back…

"Get away from her!"

And from behind, a large elliptical shield, one that was slate grey with eight spikes around tis edges, flew forward and cleaved right through the legs of one of the Krabs. Surprised, it topped to the ground and fired of its laser, hitting the Krab on its right on the underside of its shell, making it stagger back from the blow. The same shield also shear through the left two legs of the third Krab, before hitting a wall and imbedding itself there.

Aelita opened her eyes and blinked in shock. Rushing towards her, in the direction the shield had come from, was a boy. Standing at least 1.75 meters (approx. 5 ft. 9 in.) and powerfully built, he looked like couldn't have been much older than she was. He was clad in what looked like a full suit of plate armor, minus the helmet. The gauntlets ended spiked knuckles, which he used to punch at and through the mark of the now-legless Krab, causing it to burst apart.

As he stood, she was able to see his face. His ear were pointed like her own, and his hair was even pink as well, though it was such a dark shade that she almost didn't see it at first. His eyes were gray, and there he possessed a prominent jaw and forehead.

"Are you alright, Aelita?" he asked, his voice surprisingly gentle for his size and overall imposing demeanor.

Momentarily flummoxed by the strange turn of events, Aelita floundered. "Um… I… You… Who are…?" she managed to get out.

The stranger, whoever he was, looked past her and sighed. "We'll have to catch up later," he said. Rushing past her, he grabbed his shield from the ice wall it was imbedded it, ripping it out . The Krab that had staggered off before was now collecting its bearings, and immediately unleashed a wave of lasers at the newcomer.

Grunting, the boy held up his shield and let the laser hit it, dispersing along its surface as he began moving forward. Once it saw that shooting was doing nothing, it tired rushing forward and swinging with one of its legs. In response, he flipped his grip on the shield—which Aelita noticed had both a vertical and horizontal handle—and swung at the incoming leg.

The spikes at he end sheared through the limb, leaving the Krab off-balance long enough for him to jump onto its back and stab his shield through mark. He landed back on the ground and, with what seemed like practiced ease, he threw the shield at the Krab that had gotten half its legs cut off before, stabbing and destroying it as well.

Back in the Factory, Jeremy and a returned Odd stared at the screen in complete shock. "Whoa…" Odd commented, and Jeremy nodded.

Aelita was similarly awed, at least until the newcomer came closer and placed a hand on her shoulder. Startled, she looked up to find him smiling gently at her, in complete contrast to the destruction he had just unleashed. "Alright, I think this is where you do your part," he told her.

Blinking one more time, Aelita said "Oh, right!" and rushed towards the tower.

In short order, the tower was deactivated, the alien monster collapsed just before it could break into the room were Ulrich and the others were hiding, and the Return to the Past was initiated.

"SISTER?!"

After having made sure that Finson wasn't going to shoot the movie in the Factory, the Kyoko Warriors had convened in Jeremy's room to talk to, and about, their new ally.

The boy nodded from his window on the computer screen, which was alongside Aelita. "Yes. My name is Waldo, and Aelita is my younger sister. I don't quite have all the details, but apparently my purpose is to defend her and make sure she never comes to harm," he told them. Then he tilted his head. "Or at least, I'm almost certain that's my purpose."

Standing with him inside one of the Towers, Aelita shook her head. "But that doesn't make any sense. I'm an AI program, not a human being. I don't have 'sibling', or even a biological family," she pointed out.

Ulrich nodded. "Yeah, and I'm not so sure I buy the whole part about protecting Aelita. If that was the case, where've you been the whole time we were fighting X.A.N.A.?" he challenged.

While Waldo frowned and was about to respond, Jeremy interrupted, saying "Actually, I think I may have an explanation for that."

The others looked at him, and he said "I've been doing some checks on that file I found, and from I can see, you were supposed to wake up along with Aelita when I turned on the supercomputer. But maintained both her and Lyoko itself already takes up a lot of its processing power. It just didn't have enough to wake up Waldo as well."

Yumi raised an eyebrow. "What, and it does now? When did the supercomputer get stronger?" she asked.

He shrugged. "I have no idea, but it would explain why the procedure to wake up Waldo worked now, when it wouldn't have before," he replied.

Aelita focused on Jeremy. Hesitantly, she asked "So… could we really be siblings?"

Jeremy mulled it over. "Well, you both similar AI programs, likely made by the same personas well, that being whoever built the supercomputer to begin with. So in that sense, yes, you are," he answered.

At that, both Waldo and Aelita looked at each other. "I… I never even thought about having… a family. I'm not even sure what I'm supposed to do," she said.

Waldo smiled and scratched the back of his head. "Well, to be honest, I'm not too sure either. But… I'm willing to give it a shot of you are," he said, holding his other hand out to her.

There was a moment of silence, and then Aelita smiled widely. "I'd like that very much," she said, placing her hand in his.

And there's the first chapter to that. I'm on a huge nostalgia binge right now with Code Lyoko, and I've been contemplating do a fic about for a couple years now anyway. This was the end result of that.

Also, for those of you who have seen the series in full, you know exactly where Waldo got his name from. I plan on expanding on his character more in the future, but this is what I have for the first introduction.

As always, please review! If you flame me then Bruce Lee will smash you with his nunchaku. (I'm just kidding… or am I?)