IridiumRing92 here, with Chapter Four of The Final Paradox. I've been super preoccupied with other stuff lately, so I haven't been able to read many other fanfics. :P Hopefully that's something I'll be doing this week.

But anyway, here we are. I know I've been finding weird song lyrics that go with every chapter, but I had none this week. Thus my use of Worlds Collide from FFXIII-2. And while we're on that topic...I don't own any of this stuff.

So, once again, a big thank you to everyone following this story, because you're actually paying some sort of attention. XD Enjoy!

Chapter Four: Ripple Effect

Paradoxes must break

This is the path I must take

My destiny may change your fate

The pain my heart feels is my strength

~Worlds Collide

Caius moved swiftly and acted quickly. He knew where he'd last seen Yeul, and he doubled back to that time and place, resetting things as he went. If he could shield her from her fate, maybe he could go on with what he'd been planning.

He set foot in the ruins with a sense of finality in his actions. He had to be able to do something about this.

Seconds later he was with Yeul, but his mind was elsewhere. Did he have to change something to prevent her death? Had he changed anything at all? What about Serah and Noel? Had they counteracted him again?

Minutes went by without conversation. He had his back turned for a while, staring up at the ruins jutting into the sky. Yeul did the same, saying still nothing.

Then Caius turned abruptly to face her. "Yeul," he whispered.

"Yes?" she asked softly.

"We must leave here."

He expected her to seem confused, to ask him why. Instead, she shook her head, a tranquil expression on her face. "No, Caius," she said. "There is no reason."

His glare was hard and emotionless. "We have every reason."

"Leaving will not get us anywhere," Yeul answered. "Our fates are the same wherever we are."

"What do you mean?" Caius asked. His voice was flat, but his actions spoke otherwise. He took an anxious half-step toward her as though he was fighting himself, trying not to look paranoid.

"The timeline," she said, and her voice trailed off into a whisper.

Things suddenly looped back into déjà vu. Yeul fell to her knees before his eyes, and he couldn't stop himself from calling out to her just as he had done before. Her last words spiraled around him again.

Her voice was barely audible as she attempted to speak to him again. Caius leaned towards her though he had no desire to hear what she was saying. "There is no way to right the timeline… It's falling apart."

When she was gone, he stormed back through the gate. Yeul had died before him again. As if there was nothing he could do about it. He hadn't changed anything by going to Valhalla. There was only one answer to his problem: Find Serah and Noel and make sure they would never interfere with him again. They had to be the ones who'd twisted the timeline. Who else would have done it?

Caius then opened his eyes to find himself in Valhalla.

His notorious opponent stood over him, glaring as she usually did in his presence. But the image confused him. He'd stepped through that gate after witnessing again Yeul's untimely demise, not intending to end up back here.

"Caius Ballad," Lightning said with a note of annoyance in her voice. "Why can't you leave the timeline alone?!"

"I have left the timeline alone," he responded bitterly. "It's your friends who refuse to stop changing it."

"I just witnessed the change." Lightning's face stayed blank as she defied his claim. "It came from the Paddra Ruins."

Caius worked hard to keep his face straight like a mask, while underneath his emotions swirled like poison. Of course, he'd just been in the ruins. But just going back there couldn't have been enough to change the timeline, could it have? Could it have saved Yeul?

"You can't save her," Lightning hissed. "You've erased her."

He paused for only a second before standing up and drawing his sword. Within moments their blades were scraping against each other again as they dived into yet another fight.

"If you keep this up," Lightning informed him between breaths, "you'll destroy everything."

"And how do you know that's not what is necessary?" he answered, smirking.

She had no answer for that except to lash out at him again. They were at each other's throats for a long time afterwards. Caius kept his emotions veiled as he usually did while he fought, but he could tell Lightning was starting to get a little agitated with him. If he kept it up long enough, could he finish her?

With that small promise of a thought he started to fight harder. It was the only way to get out of Valhalla after all—what else would he do, retreat and run for the gates?

But their battle never reached its climax. Instead, as they tried to impale each other another time, an explosion rocked the ground and the sky around them and blasted them apart.

Caius recovered as quickly as he could, but things didn't seem quite right when he did. Lightning pulled herself onto her feet a few hundred yards away, still glaring at him, but she too had a slight expression of confusion on her face. She managed to hide it when she noticed his eyes burning into hers.

They stood there looking directly at each other for a minute. Their standoff was on hold. Something had happened, and they were both trying subconsciously to figure it out. Caius reached back through his memory until he found a rift. There was a void in the middle of recent entry.

It took him a second to make the connection between that memory and similar ones from a time much earlier.

"Yeul," he muttered intensely. Something had happened between him and Yeul, then, recently. But that was as much as he could remember.

"What have you done this time?!" Lightning asked, dashing toward him with her sword drawn.

"I have done nothing yet," Caius replied as he prepared his counterattack. "But you will die, mark my words. Whatever you are doing to the timeline shall be reversed."

"You're the one who's going to die," Lightning told him, glaring back levelly at him. "You—"

Another explosion split them apart and sent them both flying. Caius hit the dirt hard, tasting dust and blood when he landed. This time there was a significant difference in his memory.

Dark hatred resonated through him as he recognized it again. There was something else he was supposed to remember about Yeul, but it just wasn't there. Someone is erasing Yeul from the timeline.

"Why are you trying to do this?" he growled at Lightning. "Why do you try to take her away from me?"

"I don't know what you're talking about," she repeated. But there was a glimmer of uncertainty deep under her mask of confidence.

Rather than responding, he drew his sword for the thousandth time and they lapsed back into fighting.

Finally they stood apart from each other, breathing hard, yet still poised to swing at each other. Caius knew that their battle wasn't going to force Lightning to answer any of his questions, but he stood his ground anyway. Instead of flying at him with her blade outstretched, though, she hissed, so quietly that it was nearly inaudible: "What is it you're after?"

"I must know who is twisting the timeline," he said, straightening his stance.

"What have you lost?" she asked.

The question caught him off guard. A hint of a smirk appeared on her face, and he knew she'd done it on purpose. He rearranged his expression into a neutral one and answered, "You know very well who I've lost."

Her eyes searched his face. "Do you understand?" she said quietly. "We've both lost our memories. Neither of us is changing the timeline."

Common ground between himself and his eternal opponent was the last thing Caius wanted. "Enough."

She looked as if she might reply, but instead she stepped back and readied her sword.

And they launched into battle again.