A/N: I'm trying to beat the writer's block out of me. I just completed FFXIII and its fresh on my mind, so I thought I'd make this a crossover.

Marked

"You have to stop this!" Sora shouted as he jumped into the air, raising his Keyblade high to parry the incoming onslaught. "There's always another way! I can help you, just let me!" A cyclone engulfed him into its vortex, bombarding every inch of his body with explosive lacerations. Every cut made into his skin burst into painful flames until the cyclone spat him back out where he crashed to the ground. With the wind knocked out of him, Sora could do little more than groan as his opponent's boots slid next to his face.

"Don't you understand? They have Serah. Your heart for hers—that's the deal."

The enemy's blade rose high into the air in preparation for the finishing blow.

"Lightning, please!" Sora swung the Keyblade up in defense, narrowly shielding himself from a ferocious slash across the chest. The mighty blow forced him back into the air where he collided into a nearby mountainside. Dust flew up around the disturbed area, but the decline in visibility did little to deter Lightning from her goal. Stomping one foot hard and fast against the ground, she propelled herself into the air at an angle and steered straight towards her target to finish the job. Gunblade extended, she pulled the trigger and sent a barrage of bullets streaming through the dust particles until she gained enough distance to use the blade.

One final slash and the battle ended. A blade fell, hitting the ground first before the dust settled to reveal the victor.

"Why…?"

"I'm sorry."

"Just finish it."

"It didn't have to come to this."

"Words don't mean anything anymore. It's over."

"I really am sorry…but there doesn't seem to be any other way."

Another slash.

One warrior collapsed next to the fallen weapon.

It happened like it did with me. He found her wandering in search of her lost light. With nothing left except a memory, she made the perfect warrior—an almost soulless golem for him to craft into a killing machine. That's what people like me are best at: fighting and killing. It's all we know; it's the only way to prove to ourselves that we're still alive. We have hearts, but we may as well be Heartless because we don't feel them beating.

There's nothing there except a memory. One memory to keep us intact, but not enough to say we're human. We may as well be Heartless because there's nothing inside except one memory shrouded in darkness.

"Okay, here's the deal: you beat up the Keyblade master and I help you save Cindy."

"Serah."

"That's what I said. So do we have a deal?"

She looked into his eyes, ones that held orbs of dark matter for pupils and burned with an inner flame of well-concealed fury. Hades, Lord of the Dead, was a powerful deity she knew, and that's what made him untrustworthy. Lightning knew a thing or two about would-be gods and she despised them. To them, humans were nothing more than mere pets—expendable playing pieces to fulfill the whims and fancies of powerful beings that would claim ultimate authority and mastery over other races.

Yet despite her utter loathing of those who would use her as a pawn for their foolish games, Lightning found little else choice in the matter. The mark over her heart burned like no other pain she had ever known and it served as a constant reminder that time continued its countdown. One day soon, she would become like the other monsters and then no one would save her sister. Hades was her only option.

"Fine," she said without looking at the god. "I'll do it, but you'd better keep your word."

"Hey, that's why it's in writing." With a snap of his fingers, Hades summoned a contract requiring Lightning's signature. "You just sign on the dotted line, whack the Keyblade brat around senseless, and then you and Sandy will be all hunky-dory. Badda-bing, badda-boom! Everyone's happy!"

Taking quill in hand, Lightning signed away her soul.

We're not complete people, she and I. We've lost too much. The emptiness inside is a result of our losses. Nothing's left to fill the void, and that's why he could tempt us despite our better judgment. I'm not stupid, and neither is she. We both have beliefs and values—or at least we did once upon a time ago. I guess we threw them all away when we realized just how empty we were without the light.

It's easy to want a quick solution when you're desperate. We've lost too much and that's what fueled our desperation. You figure if there's nothing else to lose, what's one final gamble? All or nothing. Sell your soul; it doesn't matter. It's all or nothing.

"You won't do it?"

"No, it's not that. I'm just kind of…"

"What?"

"Well…shocked."

"You won't do it." Cloud closed his eyes and tilted his head back towards the sky.

"Hey, I didn't say that!" Sora protested. "I'm just taken aback by the whole thing—that's all. I didn't take you for the kind of guy who watched out for things like this."

"I'm not."

"Then why?"

"It's because…" Cloud trailed off, pausing for a bit before letting out a sigh. He let his eyes land back on Sora. "I know what it's like."

Sora flashed a broad smile. "I think it's admirable of you, Cloud."

"Don't read too much into it," Cloud said as he adverted his gaze.

"Ha, ha. Okay. So is there anything else I should know about the situation?"

As he leaned against the wall with his arms crossed, Cloud paused to contemplate in cool silence. "Yeah," he said after a while. "If you lose, no one wins."

I met her by chance. She woke up here in this town after the Heartless finished ransacking hers. I wasn't even supposed to be there where she popped up, but I ran out of places to hide. She was quiet and I liked that so I stayed. We both sat there not saying a word…until her chest started to burn.

She was marked—and not just anywhere. They marked her on the chest right over her heart. It burned her and she screamed in agony. I tried to help, but I couldn't. No one could. She told me her story then, thinking it was the end. They marked her and she knew the end would come soon, so she told me everything and I listened.

I listened because I was marked, too.

"Isn't there anything we can do, Herc?"

Hercules shook his head. "I'm afraid not, Phil. Lightning signed the contract, and if she doesn't follow through, Hades will sentence her soul to the Underworld."

"Then I'll just have to fight her and win!" Sora said, pounding a fist into his open palm. "It's the only way, right?"

"But what about Serah?"

"I'm working on that…"

"If Hades has her prisoner, I could pay a visit to his lair while you stay topside and fight," Hercules suggested.

"I don't think Hades is responsible this time…"

"Then who?"

"Like I said, I'm working on that."

She left to find her light just as I had done. Nothing matters to people like us. We stop caring because there's nothing left to care about. All we have is a distant memory of a time when we knew what it meant to be full of light. Our light is taken, and people like us leave to find it. We have nothing. All is nothing because nothing can fill us except the light we've lost.

She left to find her light, but what she found waiting for her was more darkness. It preys on people like us—tempts us into believing there's no other way. Darkness pours in to fill the void left by our stolen light. She thought the darkness would deliver her. She thought wrong.

"Lightning!"

She stopped, her jaw left slightly agape as she eyed the young Key wielder.

"That's your name, isn't it?" Sora asked as he lowered his weapon. The two had fought for just over a minute in the final match to decide the victor of the Olympian Cup. Neither warrior exchanged a single word until Sora bounced back from a parried blow and called out his opponent's name. "Lightning, a friend of mine has told me what you're going through and I can help you. You don't have to worry about your sister anymore. The only thing needed is for you to void the contract you struck with Hades."

"This fight isn't about Hades."

"What?"

"It has nothing to do with him."

"Hang on a minute. If we can cut Hades out of the equation, then I can help you all the better. Just trust me!"

"I can't."

"Why not? Helping out friends-in-need is what I do best."

"I can't."

"At least give me a reason!"

"I can't…because I did all of this…" Lightning twirled her Gunblade and slide into an offensive stance. "…Just to lure you out!" She launched herself at the Keyblade master.

"What?"

"They want you." The Gunblade came crashing down onto the Keyblade. "It's you, Keyblade master; it's always been you."

Sora slipped free from Lightning's rampant assault, trusting all his moves into his footwork as he dodged every blow without retaliating. "'They'? Who's 'they'?"

"Enough talk! Fight!"

Summoning all her strength, Lightning unleashed a merciless chain of rapid attacks that left Sora defenseless. The finishing move channeled enough energy into the Gunblade to bat Sora clear out of the coliseum. He streaked across the sky and vanished into the horizon within seconds. But just as the trumpets sounded to signal Lightning's victory, she herself jumped clear out of the ring and bounced atop the surrounding stadium seats to gain enough momentum to follow after her mark.

Far away from the coliseum in the middle of the barren desert, Sora crashed headfirst into sand dune and tumbled through until he landed flat on his back. He stumbled back onto his feet and swaggered over to the foot of a mountain not too far from his landing site where he leaned against the rock to regain his composure. But no sooner did he stop to take a breather when Lightning touched down in her own sand dune.

Sora shifted into a defensive stance, swinging the Keyblade up to guard his torso. "It's not too late for me to help. Just tell me who's responsible for all of this."

But Lightning didn't reply. She instead charged up to Sora and picked up where they had left off in the arena. The two fought, and they fought, and they fought some more without holding anything back. The battle intensified with every blow until their movements created a miniature sandstorm to encompass the battleground.

"You have to stop this! There's always another way! I can help you if you just let me!"

Finally, Sora was forced to the ground with the Gunblade's point poised mere centimeters from his head.

"Don't you understand? They have Serah. Your heart for hers—that's the deal."

But the battle didn't end there. It waged on, for Sora would never give up on a friend—especially one who lost someone dear to her heart. So he held on fast to the Keyblade, and when she came at him for the final time, he somersaulted out of the way of her blade, allowing it to lodge itself within the rock. Lightning couldn't free her weapon fast enough, and the next thing she knew, the Gunblade was at her feet and the Keyblade at her throat.

"I really am sorry," Sora said, his voice weighed by weary sadness, "…but there doesn't seem to be any other way." He slashed the Keyblade through the air and twirled it around his hand, striking Lightning on the back of the head with the Keyblade's pommel and knocking her unconscious.

It's hard to know anything different after living in darkness. Killing just seems natural in a dark world. What's killing a kid if it'll save your own kid? What about killing someone's sibling if it'll save your own sibling? Where does it stop? Is there a line? If she were left in the darkness any longer, she wouldn't have known a line. She wouldn't have even felt the void anymore. After knowing nothing but the empty void for so long, one forgets there was ever anything else but the void.

But there's more—a lot more. The darkness leaves its mark. You never forget the hold it has over you. People like us are marked to remind us that we're empty. We're marked to remind us that even if we find the light once more, the darkness will still be there. Darkness is a part of her like it's a part of me. Even if she finds her light, she'll still be marked.

"Why didn't you kill me?" Lightning asked from her handcuffed position on the floor.

"Not this again…" Sora sighed. "You asked me that five minutes ago when I brought you some lunch and ten minutes prior to that when you first woke up. How many times will it take before you understand that I'm a friend who's trying to help?"

"I'm your enemy," Lightning stated blatantly, nudging the tray holding the un-eaten meal back towards Sora with her foot.

"What you are is the official loser of the Olympian Cup, and therefore free of Hades' contract," Sora said, pushing the tray back towards Lightning. "As such, we can freely converse without any strings attached. So why don't you tell me who really put you up to this?"

Lightning didn't answer.

"Are you afraid to tell me? Will they hurt your sister if you talk?"

A long pause ensued before Lightning replied. "…Maybe I was wrong."

"About what?"

"You." She turned her head to look straight at him.

Sora rubbed the back of his head. "I hope that's a good thing…"

"They chose my sister because they said she was special."

"Who did?"

"I don't know what they call themselves, and they stayed hidden in the shadows so I never got a good look at them."

"Well, gee. That sure narrows it down…" Sora sighed and shook his head. "Anything else you can tell me?"

"Serah…she's…" Lightning closed her eyes. She couldn't bear to say it.

"She's what?"

"Found."

"Huh?"

Both Sora and Lightning turned their heads towards the door where Cloud was leaning in the doorframe.

"What did you say?" Lightning asked with wide eyes.

"You heard me," Cloud said. "We found her—well, Donald and Goofy did the search. I just went along as the resident muscle. But we got her back."

Sora jumped up with joy. "That's great! Ha, I knew splitting up would work better in the long run." Extending his hand, he summoned the Keyblade and aimed it at Lightning. With a smile, he turned the Key and the handcuffs fell to the ground.

"Where is she?" Lightning got to her feet and approached the door. "Is she safe?"

"She's marked."

Lightning's mouth went dry. "Is she safe?" she asked again.

"For now," Cloud replied. "But that doesn't change anything."

The two stared at each other in silence, leaving Sora confused. "What are you talking about?"

Seconds passed, followed by minutes before anyone even glanced in Sora's direction. Then Lightning tilted her head and opened to her mouth to reply, but a pain-filled scream escaped her lips instead. She collapsed to her knees, clutching her chest. The mark burned.

People like us are marked. We can never forget our fate or escape it.

But there's a difference between her and me—a big difference. We feel the void and the darkness; know what it's like to exist only in battle; let go of everything but the darkness and a faint memory of light. Our mission in life is to find the light we've lost. That's what we have in common.

The difference lies in our actions once the goal's been met. We're both marked, but she never ran once—never hid. When she found her light, she never lost sight of it again.

"Serah!" Lightning opened her arms wide as her sister ran into her welcoming embrace. "I'm sorry. I'm so sorry about—"

"It's okay," Serah whispered, cutting her sister off mid-sentence.

"No, it's not. From now on, things will be different." Lightning pulled back to look her sister in the eyes. "I'll always be there for you and listen to everything you have to say. If I had just done that in the first place, none of this would've ever have happened."

"Well, if you put it like that…" Serah's glance drifted over towards the far end of the room where Sora and Donald were playing keep-away with Goofy's hat while Cloud leaned against the wall looking on in amusement. "I would've never have met those guys. They're good friends, don't you think?"

Lightning smiled. "Yeah."

"So don't beat yourself up about it. Okay?"

A knock sounded on the door and the three musketeers stopped horsing around. Sora went to answer, but the door burst open on its own and a woman walked into the room.

"Oh, it's you!" Sora exclaimed. "Still looking?"

"'Fraid so…" Tifa sighed. She took a look around the room, noting the two new arrivals and the opened window along the back wall. After checking under the bed, behind the armoire, and in the fridge, Tifa shook her head. "Nope, not here, either. Oh well, I won't give up! I'll find him eventually."