Aqua kept his pace well, considering she hadn't completely recovered from having her darkness awakened and she also had to fight off Heartless around every corner. These were only the normal Heartless though, only there because they had no better place to be, not specifically targeting Aqua for her light. The dark suit had done its job in that regard.

As far as Vanitas could smell, they were making progress. Very, very slight progress, but as they navigated the maze of pointed stones and walls, the heart of the Realm of Darkness grew more distant.

They were still too close for comfort. They hadn't started quite at the Realm's technical epicenter, thankfully, but Vanitas could only imagine how much farther they had to go.

"Are you sure we're not going in circles?" Aqua asked.

"I'm more sure than you are," Vanitas replied defensively. The rocks did look pretty similar, but rocks were rocks. It wasn't like he expected much variety.

"That isn't saying much," Aqua mumbled.

"Do you want to lead the way?" he asked, more than a little irritated. His sense of smell was the only compass they had to go by. What right did she have to question it?

They turned a corner, entering a room of sorts. The rock walls curved upwards to form a dome with a small skylight at the top—if there had been any light in the sky. Two paths diverged on the opposite side of the room, one on the left with spikes jutting from the walls, one on the right shrouded in a mist so dark that Vanitas could only see a few feet into it.

Aqua immediately began walking towards the spiked path.

"Where do you think you're going?" Vanitas asked. His sense of smell caught thick, cloying vapors coming from the left. The mist, while ominous-looking, practically smelled like a holiday candle in comparison.

"Not that way." She nodded in the direction of the misty path.

"Then you're going the wrong way." He grabbed her wrist to pull her back on track, but she jerked away.

"That can't be the right way. It's getting darker."

"Look, your road's going to get just as dark once you get in there, and you won't be able to find your way back. Stop being stupid and follow me." Vanitas headed off towards the mist.

"No." Aqua stood firm, navy blue boots planted on the cold stone ground.

"Excuse me?" He put his hands on his hips. "This is my world. You don't belong here any more than I belonged in the Realm of Light. You won't make it out without a guide and you know it."

"I've made it this far," she countered.

"Only because I saved your life."

He knew she didn't have a retort for that when she looked away, back towards the splitting paths. "I go left. You go right. Then we'll see whose path reaches an exit."

"You won't see anything if you're dead. And even if you somehow don't die, you'll be lost forever." Why did she have to be so stubborn about it? He was right, and she was wrong. It wasn't complicated.

The smell only grew stronger while she wasted their time. Was the source of the scent getting closer? It was thicker than ordinary darkness, more… alive. Like a Heartless with extra bad breath.

"Remember who it was that defeated you. Several times over." Aqua's voice was colder than her eyes, which glinted in the ambient blue light like chips of ice. "I am a Keyblade Master, and I earned my rank. Don't underestimate me."

Her sharp tone set him off.

"When are you going to realize that doesn't matter? Nothing from the Realm of Light matters here! Heartless don't care who you are!"

"I'm perfectly capable of—"

"Stop deluding yourself," Vanitas snapped. "Go left, fine. Get yourself killed. But don't come crying to me when you find out what's back there."

He couldn't be sure exactly what was back there either, but she didn't need to know that. Whatever it was had to be powerful, and Aqua was still weakened, no matter how how stalwartly she carried herself.

"We'll see," she replied with calm determination. "You'll see. I won't remain tied to the darkness."

Vanitas rolled his eyes, not that she could see. "Of course, that's what this is about. You're going to throw yourself at that monster's feet for your pride."

"Monster?" That finally got Aqua's attention. "You didn't say anything about a monster."

"Did I need to? I told you, there's a mass of darkness in that direction. Just because you can't see it yet doesn't mean it's not there."

He wasn't really bluffing. What else could the awful smell be?

But Aqua had chosen her path, and clearly her pride wouldn't let her change course.

"Then I will defeat the monster, and leave this place a little lighter."

He smacked the front of his helmet in exasperation.

"That's not how it works, Aqua. Aqua—!"

She was already heading into the spike-filled crevice.

"Fine!" He yelled after her, probably drawing the attention of any Heartless in a mile radius. "If you want to die, I don't care! I don't need you!"

He didn't. He thought she might be an asset, or at least something of interest, but clearly the girl was nothing more than a liability. She wasn't worth his worry.

He stalked off towards the darker right path. He didn't need her. He'd known she would leave, just like every light did.

The only one he could trust was himself.

XXX

The thick, dark mist messed with his senses. It numbed his suited skin with a cold, tingling sensation. It filled his nostrils with must and mildew. It dampened the faint sound of his footsteps; it blinded his eyes so he could only rely on his palm against the wall for direction. Even his mouth, when he tried breathing through it, tasted the darkness. It was his element, but that wasn't much of a comfort now, when it took away nearly all of his connections with the outside world. He almost wondered if Aqua had been right.

Almost. Even this dark mist had to be better than what she would go up against. Whatever it was.

How long had he been walking? Time never flowed consistently in the Realm of Darkness, and without any landmarks, distance was just as nebulous. The only indication he was making progress at all was the slow leftward curve of the wall. Occasionally a Heartless' glowing eyes illuminated a patch of darkness. He kicked a few Shadows out of the way, and they skittered off.

"Stupid Heartless…" He conjured a Yellow Mustard out of his irritation, and it hovered shakily less than a foot in front of his face. A spark jumped from it to Vanitas's nose; he sliced the Unversed through with Void Gear only to feel his heart writhe as he reabsorbed the negativity.

"Can't you idiots do anything right?"

Much as he hated to form another incompetent Unversed, he wanted to see, so he produced a Red Hot Chili. At least those were a little less spastic. It wasn't as bright as the Yellow Mustard, but it was still a better lantern since it didn't bounce as much. It might be even easier to see if he removed his mask, but he'd rather keep the majority of the dark mist filtered out.

As the wall curved more sharply leftwards, it grew slimier and knobbier. Thank Kingdom Hearts for his suit. He wondered if Aqua appreciated hers as much… he doubted it. Nothing would please that girl. Not that he'd tried to.

He shouldn't waste his thoughts on her. She wasn't worth it.

Unfortunately, there wasn't much else to think about except how bored he was.

Wonder if she found that giant Heartless yet. It probably ate her for breakfast. Is it breakfast time? His stomach had always felt empty since getting stuck down here, but somehow he knew he couldn't die of hunger. That was a good thing, since he doubted there was anything edible down here other than HP orbs, which weren't as much food as they were sustaining energy.

Vanitas stopped briefly and tried another scent check, but the mist was still interfering. If anything, it smelled even darker now, sourer, more stomach-churning. By the light of the Red Hot Chili he saw the knobby wall recede, thin out until it became spongy and porous. But it wasn't the wall that made him take interest; it was what he could now see through it.

"Aqua?" He called in the brief second he could see, before the mist shifted again and enveloped the other keyblade wielder in darkness.

Was his mind playing tricks on him? No, it had to be her.

(Otherwise this place was getting to his head—)

He heard no reply. Maybe she hadn't heard. Maybe she was ignoring him. Maybe she thought she was hallucinating.

He grabbed his flaming Unversed and shoved it against the sponge-wall. It squirmed, but he held it tight between the wall and his chest. He had to see something…

He didn't. Not by the light of his Red Hot Chili, anyway. With an earthshaking roar, the yellow glow of two enormous eyes cut through the fog like spotlights, landing directly on Aqua. Her glare and bared keyblade, flashing to life with a charge of light, said 'do your worst.'

"Aqua!" Vanitas yelled again.

She must have a death wish. She didn't know what that thing was—he didn't know what that thing was, just that it was pure darkness and pure evil, on a deeper scale than even the heart of darkness himself. Vanitas could only hope it possessed less than a fraction of his human intellect.

The monster roared again, and the sound reverberated in the walls. Aqua's battle cry was pitiful in comparison as she charged in the direction of the eyes, her dead master's keyblade held high.

"Who does she think she is, Terra?" Vanitas growled, pounding the wall with his fists, which bounced off harmlessly.

She must really think she has something to prove… Or she's just an idiot.

Vanitas couldn't tell what exactly knocked Aqua off her feet. She probably couldn't, either. Suddenly she was flying back, head cracking against the far wall. The mist closed in around her—

Before he realized what he was doing, Vanitas was hacking at the spongy wall with Void Gear. A few chunks squelched off and plopped to the ground.

"No way is some stupid Heartless going to kill her without my permission," he swore, throwing all of his weight into his strikes.

The Red Hot Chili hovered into his blade's path and instantly burst into smoke. He barely registered the pain of its destruction, and the Heartless' glowing yellow eyes gave off enough light to keep hacking.

With a shout, he finally carved out an almost-Vanitas-sized hole, which he ungracefully squelched through. His head swiveled back and forth in search of Aqua, but all he saw was darkness. And the eyes.

And the eyes saw him.

"I really thought this through," he muttered sarcastically. In desperation he fired a Dark Firaga at the eyes that sped towards him. The attack was barely bright enough to illuminate the monster's massive maw, which swallowed the Dark Firaga as easily as Ventus would have swallowed ice cream.

Vanitas was about to be the next scoop.

He barely dodge rolled away from the stalagmite-sized teeth, which clashed together like nails on granite. He'd run in just as stupidly as Aqua—where was that girl? The monster couldn't have eaten her—

I mean, I said it was going to eat her, but… nngh, why do I freaking care?!

"Curaga," a faint voice floated from across the cavern. Vanitas was surprised he could hear her through the mist, and that she hadn't been knocked unconscious.

The yellow eyes abandoned Vanitas, immediately locking their searchlight beams on Aqua, who stood without shaking.

So now she could cure. What was wrong with her before?

The monster was fast, but now that she was prepared, Aqua was faster. She cartwheeled to the side and cast Thundaga, which bolted down on what Vanitas guessed was the monster's skull. Not willing to be shown up by the girl he was trying to save, he shot Dark Blizzaga into the side of its head, but it didn't even flinch. Its misty skin seemed to absorb it.

"That's not helping!" Aqua called, the first indication she'd even noticed his presence.

"Hey, don't go whining when I try to save your life, again," Vanitas retorted. "You could've—"

"Behind you!"

He stabbed backwards without questioning her, but it didn't make a difference. He'd stabbed right into the monster's open mouth. He barely pulled back in time to save his arm from the massive teeth.

His keyblade wasn't so lucky. A shadowy outline of a Cheshire grin stretched across the monster's face as it swallowed his weapon.

"Joke's on you, idiot." Vanitas rolled his eyes, holding his palm out to summon Void Gear.

Nothing happened.

"What—?"

He clenched and opened his fist. Still nothing.

Oh, he was going to murder that thing. …As soon as he figured out how.

"Get down!"

Aqua leapt at the monster in a frantic Time Splicer, leaving ghostly afterimages of herself as she attacked over and over again. The monster momentarily froze, and once Aqua reappeared next to Vanitas, it writhed from the multiple blows at once.

"I always hated that move," Vanitas muttered.

"I know." Aqua sounded smug. Almost like himself.

But they didn't have time for banter; the glowing eyes pounced at them both, and Vanitas's keyblade still wouldn't appear. He was little more than a meat shield.

Aqua's cartwheel faltered, and a plume of black mist form the monster's maw choked her, hiding her from Vanitas's sight. He tried another Dark Firaga, Dark Thundaga, anything—why wasn't it working?

"Enough!" Aqua shouted, dispelling the dark cloud with a trio of flame-pillars: her Raging Storm command. She coughed out smoke as the bright fire not only seared the Heartless—it allowed Vanitas to see it clearly for the first time.

He'd expected it to have a body. Instead it was more like a massive Darkball—All face. Hideous, ugly face, with a tangled mass of dark veins framing its yellow eyes and stalagmite-filled mouth. Some of the veins had been cut open where Vanitas and Aqua (mostly Aqua) had damaged it, but each broken vein released more toxic smoke into the already-saturated air.

"Are you going to help me or not?" Aqua asked, irritation and fatigue showing as she dodged and jabbed at the giant face.

"If you haven't noticed, I've tried," he growled. "We should run while we still can. There's an escape—"

She cried out as the giant jaws bit down on her arm, but her dark suit somehow absorbed most of the blow from the shadowy teeth, like how the Heartless' skin had absorbed Vanitas's attacks.

"No! I started this, and I am going to finish it!"

Switching hands—her keyblade arm had been bitten, but the blade itself was fine – she flew into a combination of strikes and magic volleys, glowing purple when she activated her Spellweaver command style.

She was doing better than Vanitas gave her credit for. Maybe all she needed to fuel her victory was something to prove, and someone to prove it to.

Still, Vanitas wasn't about to let her one-up him, not when he'd told her she'd get herself killed without him. But what could he do? He was keybladeless; his dark attacks weren't damaging it—

Dark. It was a higher class of Heartless, much darker than even himself. Of course it would only absorb the dark attacks. No wonder Aqua, with her brighter magic, was finally gaining the upper hand.

His non-dark magic was painfully unpracticed. Xehanort had never encouraged him to hone it. His Thundaga and Firaga spells were so steeped in darkness, he wasn't sure he could do them separately; Blizzaga was his best bet and easiest to cast without darkness' influence.

"Freeze!" He snarled as Blizzaga burst from his palms.

The chunk of ice hit the monster's back—if it had a back—and it roared at the unexpected pain, giving Aqua time to prepare her powerful Ice Barrage command, which added to the ice damage and unleashed her Bladecharge command style.

The monster Vanitas had thought was so powerful didn't stand a chance. The ice had slowed it down, and it couldn't get close to Aqua without flinching away from the searing light enveloping her keyblade.

Yes, the monster was dark. But its darkness had never been tested against the light, and now it received a rude awakening.

Vanitas didn't bother pretending to be useful this time. He stood back and watched as Aqua deftly spun her oversized lightblade and sliced it down between the monster's yellow eyes. Those eyes dimmed, dimmed until they melted into the darkness.

Unlike the Heartless from the Realm of Light, no heart floated out of the monster's remains. It had likely never had the opportunity to steal one.

While no heart came from the destroyed Heartless, something else did. Vanitas's keyblade clattered to the ground.

Aqua, her command style glow fading, picked up Void Gear. When she turned back to Vanitas, a tiny smirk graced her lips.

"Who saved who now?"

He snatched his blade from her, more comfortable with its weight in his tight fist.

"Boasting doesn't suit you, Aqua." Just because she got lucky one time…

"I am confused about one thing, though," she admitted, dropping her satisfied pride. "Even if it was pointless, why did you try to save me at all? I thought you didn't care if I survived."

Vanitas snorted. His mind didn't care. The rest of him, for whatever reason, seemed a little more indecisive.

"Come on, Aqua. You of all people should know better than to trust me."

She gave him a wary look.

"Is that your way of admitting that I was right to choose my path?"

My path, like she owned it. Ugh. With the monster gone, and its rancid stench dissolving with it, he could tell that this path actually remained lighter from here.

"No, I was just reminding you that I lie. But if you want responsibility for whatever other messes we get into, fine. We'll take your path."