(Battle Music Cue: Hunter of the Dark - BBS FM)

In Twilight Town, Kairi, Ven, Terra, and Axel all stood at the ready, their weapons summoned before the Unknown. The Unknown was stood with its sword drawn, standing with its eyes fixed upon the four of them, not looking at any one of them specifically.

"There's no need for violence! We don't need to fight! Let's all just lower our weapons!" Kairi said, hoping the Unknown would do so. The Unknown looked towards her before launching itself forward, running towards them at high speed. The four quickly braced themselves for the inevitable fight just as the Unknown leapt into the air, sword pulled back with both hands, the blade pointed towards them and suddenly beginning to fill with dark energy. Terra saw the energy and his eyes widened.

"MOVE!" Terra yelled, quickly moving to block as the other three leapt clear. Terra brought his Keyblade around in time to block the attack, the tip of the sword hitting the side of his Keyblade, sending out a black shockwave from the ferocity of the strike. Terra then effortlessly swung the Keyblade, throwing the Unknown into the air. He then quickly swung at the Unknown, sending a sudden flurry of swings at it so fast that only streaks of light of his blade reflecting in the sun could be seen but the Unknown retaliated with a single swing of its sword, leaving black streaks behind in the air, their blades meeting and clashing off of each other. The Unknown then landed on the ground and saw Ven and Axel charging towards it from its left and right.

"Come 'ere! We'll make it all stop!" Axel taunted but the Unknown narrowed its gaze at him before cartwheeling backwards, engaging both men in a fast fight, easily deflecting their attacks with lightning fast speed and reflexes. Terra and Kairi both watched the sight with increasingly disturbed expressions.

"This guy's fast." Terra muttered before charging forward. The Unknown saw him coming and sent Axel and Ven flying with a single swing, quickly moving to block Terra's attack but was stunned when Terra slid to a stop, Keyblade held down at his side with both hands, petals of pink energy flowing around him. The Unknown wasn't sure what to make of Terra's move when he suddenly vanished and reappeared behind the Unknown, his Keyblade held out to one side. There was a loud and piercing metallic sound of metal striking metal as the Unknown's sword was sent spinning into the air behind them. Terra spun around towards the figure who similarly turned towards him, glaring at him.

"Disarmed?! No one's ever been able to deflect the Zantetzukan before!" Ven remarked as he climbed to his feet, Kairi helping Axel up at the same time. Terra then launched towards the Unknown but the Unknown didn't move save to raise its hand towards Terra.

"Try and fight me without a weapon!" Terra dared but slid to a stop when he saw a small flash of light appear in the Unknown's hand, the Unknown's sword appearing in its hand, pointed towards Terra who slid to a stop just an inch from the blade. The figure was in prime position to kill him by running him through the throat when a blinding flash of light appeared to its right, forcing it to shield itself from the light, allowing Terra the opportunity to slip away. The Unknown turned towards Kairi who held a bright sphere of holy magic on the tip of her Keyblade. The sphere then dimmed out.

"Axel! NOW!" Kairi yelled, the figure looking at its feet in time to see Axel's chakrams spinning vertically around its feet, leaving a fiery trail behind. The Unknown didn't react as the chakrams suddenly created a pillar of flames beneath the Unknown's feet.

"Did we get it?!" Ven asked but Terra snarled.

"Don't count on it!" he replied as they waited for the flames to die down. Sure enough, they saw that the only thing left behind was the Unknown's sword driven straight into the ground in the center of the flames, the fire still burning around it on the ground.

"I don't like this! Where'd he go?!" Ven asked. Kairi was looking around when she sensed something near her. She quickly leapt forward, spinning and throwing a Holy Sphere at where she had been standing. The sphere was suddenly dispersed by something unseen, the Unknown appearing out of thin air, charging at Kairi. Kairi didn't have time to react. The Unknown was too close with a hand reared back behind it. They saw a third sword appear in the Unknown's hand just before it was thrust towards Kairi, the Princess of Heart flinching as the sword blade thrust past her head, missing her by mere inches. The Unknown froze with a perplexed look in its eyes before narrowing them and turning the blade horizontally and attempting to swing at her neck but she ducked down just in time, the blade missing her by inches and not even splitting a single crimson hair. The Unknown quickly back flipped away, putting some distance between it and Kairi, looking at Kairi suspiciously before looking at the sword curiously. Kairi looked back at the Unknown, confused at the turn of events. Terra, Ven, and Axel were similarly confused. That is until the figure narrowed its gaze at Kairi.

"Princess." The Unknown said in its low masculine voice before stabbing the sword into the ground and then charging towards her, making a fist. Kairi quickly moved to block but the Unknown easily sidestepped her move and dealt a powerful blow across the face, sending her flying.

"KAIRI!" Ven and Axel both exclaimed as Kairi tumbled to the ground, unconscious from the blow. The Unknown stared at the unconscious Princess of Heart for a moment before suddenly stepping to the side as Terra attacked from behind with renewed ferocity.

"No one harms my friends, especially her, and gets away with it!" Terra yelled as the Unknown conjured a fourth sword and moved to attack but was startled when Terra quickly swung towards its head, the Unknown just barely blocking in time, their blades ringing out upon impact.

"I don't know what kind of weapon you're using. It's similar to a Keyblade, I get that, but I can tell it isn't! So who are you?!" Terra asked, keeping the pressure on the Unknown to answer.

"We weren't looking to start a fight! You attacked us head on! I assure you that making an enemy of us will not end well for you!" Terra said but the Unknown glared at him defiantly. The figure suddenly spun to the side, causing Terra to stagger forward from the sheer force of his attack, the Unknown tripping him up, causing him to fall to the ground and land near Ven, Axel, and Kairi. The three looked to see the Unknown stab its blade into the ground. They then saw the three swords around them start to let off black magic energy before perfectly round circles appeared around the swords.

"What is this?" Ven asked as Terra's eyes widened. He knew the figure was about to unleash a particularly devastating attack. The figure was about to make its next move when the three noticed a blur fly past them and towards the figure. The figure spun away, shielding its face as they heard the sound of tearing fabric. (End battle music)

"What?!" Terra asked as they saw the Unknown's cloak had been ripped off and seemed to be floating on its own but this soon was proven not to be the case as the cloak moved to the side, revealing Riku with his Keyblade summoned, the cloak dangling on the tip of his Keyblade, glaring at the Unknown.

"I don't know what's going on, but you've got some explaining to do!" Riku said as Xenix hurried up next to him, her Keyblade summoned and ready to fight although her nervousness was obvious in her stance and the small beads of sweat forming on her brow. The Unknown was partially unmasked, the cloak gone, revealing a head of short and mildly spiked brown hair. Their face was still obscured by their arm but the look in their eyes showed surprise as it looked at Riku. The figure then clinched its eyes shut, shaking its head before glaring at Xenix, studying her curiously for a moment.

"It's not her." The Unknown muttered before turning and running for the railing along the edge that overlooked the city below the train station. The swords that were driven into the ground suddenly vanished, one reappearing in the Unknown's hand. The Unknown looked over its shoulder towards them, its face obscured by its shoulder and part of the collar, staring at them defiantly for a moment before leaping into the air and diving down off the rail. Riku quickly threw away the torn cloak as he ran towards the edge but when he reached it, he saw only a closing Corridor of Darkness.

"Got away." Riku mumbled, pounding a fist into the railing. They then heard a moaning sound and turned to see Kairi, cradling her left cheek where the Unknown had punched her, sitting up as their armor all disappeared back into their shoulder guards.

"What happened?" she asked, still dazed from the attack.

"You got T.K.O.-ed in one hit just now." Ven replied as he helped Kairi to her feet, casting a Curaga on her in the process, immediately reducing the swelling in her cheek.

"Who was that punk?" Axel asked as Riku glanced at Xenix for a moment with curiosity.

"He left when he saw Xenix." Riku mumbled.

"What was that?" Terra asked.

"The attacker left when he saw Xenix." Riku replied as they looked towards Xenix who looked at them nervously.

"Why are you staring at me like that?" she asked, afraid of what they'd do.

"It's okay Xenix. You've nothing to fear from us." Kairi said reassuringly.

"But it does seem odd that this strange attacker shows up and then flees when you appear." Terra said as Xenix scratched the back of her head.

"But I don't know them. At least I don't remember knowing them." Xenix replied, unsure of what to think.

"But why did we get attacked in the first place? It's not like Xenix drew him here." Ven said.

"Actually, she might have without knowing it." Riku replied as everyone looked towards him.

"Why's that?" Axel asked as Riku looked towards Kairi.

"Kairi, when Roxas's power was growing, he unconsciously reached out to you. Remember?" Riku asked as Kairi thought for a moment and then nodded.

"Yeah?" she asked, unsure of where he was going with his questioning.

"Master Yen Sid told me that as Xenix grew stronger, her growing strength may draw out those who knew Xenix before she lost her heart, including those who might've stolen her heart. I suspect that this attacker was someone drawn here by Xenix's growing skill with the Keyblade. I think the reason they fled was because they sensed that Xenix wasn't her other. That she was a Nobody." Riku explained as the others looked contemplative but Xenix looked visibly afraid.

"I…knew that person?" she asked.

"It's okay, Xenix. We won't let anyone harm you." Ven said as Axel grinned and tapped the side of his head.

"We may not be the best bodyguards around but when we make a promise like that, we won't break it. Got it memorized?" he asked. This helped ease Xenix's fears considerably.

"Okay." She replied.

"Come on. Let's go see where Hayner, Pence, and Olette got to." Kairi said as she, Ven, Xenix, and Axel started for the tunnel entrance.

"You guys go on ahead. We'll catch up later." Riku said, Kairi giving them a nod with a smile as they entered the tunnel, leaving Riku and Terra alone in the station courtyard.

"Okay, what happened?" Riku asked as Terra took a deep breath, a look of concern on his face.

"Whoever that person was, they were skilled. Every move we made they countered with ease. They also possessed some advanced magic skills. I saw them setting up for a very powerful attack when you arrived. What bothers me the most is that sword they used." Terra explained as Riku gave a nod.

"Yeah. A sword that functions like a Keyblade yet isn't." Riku said as Terra turned towards him.

"Keyblades come in two varieties: Skeleton and pin-tumbler. The forms are strictly cosmetic in nature though. That sword was neither one." Terra explained.

"How did Kairi get knocked out, by the way?" Riku asked.

"We thought Kairi was a goner for a moment but the guy just missed each thrust and swing with its sword every time it came close to her. I heard him say the word 'Princess' before punching her." Terra said as Riku took a deep breath.

"He knew how to counter a Princess of Heart's natural resistance to Darkness. The blade must've been formed of solidified darkness magic so it avoided her each time. Whoever this person is, it's like they knew how to fight against Keyblade Wielders." Riku said as Terra looked towards the station.

"We need to tell this to Yen Sid. He may know something." Terra said as Riku nodded.

"Yeah. Let's go."

A few minutes later in Yen Sid's Tower…

Yen Sid sat at his desk, listening intently with his usual stern gaze, as Riku and Terra both finished their report on their encounter with the unknown assailant.

"And you say this sword evaded Kairi but direct physical attacks with their hand connected?" Yen Sid asked as the two gave a nod.

"I also recognized the groundwork for a technique they were about to use, a powerful magic technique. A technique like this." Terra said, illustrating a triangle in the air with his fingers. Yen Sid's eyes widened.

"A Trinity Mark." He muttered.

"I've heard of those. Sora found a few on his first adventure." Riku said.

"They are a powerful and advanced magic technique. It takes great practice but they can be used to combine different spells together and amplify their effects or they can be used to simply amplify other, more basic spells or even amplify existing trinity marks. Their uses are virtually limitless." Yen Sid explained.

"Master Eraqus was just beginning to show Aqua the Trinity Marks given her aptitude towards magic. She told me about them before our Mark of Mastery Exam. That's how I recognized it." Terra replied.

"I guess that a mark as big as Terra's implying would've had a devastating effect." Riku said.

"A Trinity Mark's size does not always correspond to its power. What matters is their intricacy and how detailed the three points are. But that is irrelevant for now. I find this report very disturbing." Yen Sid said as Terra and Riku both gave a nod, Terra crossing his arms over his chest.

"You're not the only one." Terra muttered as Yen Sid looked towards Riku.

"You say the attacker fled when they realized Xenix was a Nobody?" Yen Sid asked.

"Yes sir. I believe your warning about former associates of her other has come to fruition." Riku replied as Yen Sid sat back in his chair in thought.

"Then I believe that this will be the last we see of this attacker for now. You're all on alert for them now. Attempting a second attack now would be foolhardy." Yen Sid said before reaching into his desk and pulling out a bundled stack of four envelopes.

"Lest I forget, these came for you, Terra. They're responses to your…invitations." Yen Sid said as Terra quietly opened each envelope, took one look at the letter inside and then discarded them.

"They've all agreed." Terra mumbled, mildly surprised.

"Is this in regards to what we discussed recently?" Riku asked as Terra nodded.

"Yes. Now I just need to ask Axel, find the others, and one replacement." Terra replied as Yen Sid rose to his feet.

"I leave that for you to deal with in your own time. For now, leave me. I need to look into this matter of the assailant on my own." Yen Sid said as the two bowed.

"Yes master." Terra replied.

"We'll continue Xenix's training. Please, let us know if you find anything or if you hear anything from Sora or Aqua." Riku said as Yen Sid gave a quiet nod. He watched the two leave his tower, even watching them as they boarded the train back to Twilight Town before turning back towards the center of his study. He walked to the bookshelf and guided his finger across the shelf until he found a particular book. He pulled this book from the shelf and opened it up, flipping through the pages until he found a drawn illustration of a figure in a similar cloak and mask like Riku and Terra had described with a description written on the page to the left. Printed in the top outer corners of the page was a strange T shaped symbol but the upper bar of the T was curled upwards slightly like a pair of demonic horns while the bottom bar was shaped like a sharp blade. In the center was a round circle with several black skulls scattered within it. This symbol made Yen Sid scowl, recognizing it immediately.

"Not since the Keyblade War have one of them been seen. Now, after all these years, a Hunter of the Dark appears. Is this a prelude of what is to come?" Yen Sid asked before turning towards his desk. He then headed for his desk and opened one of the side drawers, pulling out the blue book with the golden letter L on the cover. He immediately opened it, flipping through the pages, searching for the answers until finally he lowered the book.

"This is a different danger. The enemy is returning." Yen Sid said as he started pulling books from his desk and flipping through them, beginning a long search for the answers to this new mystery.

"I wonder…if the Nobody unknowingly called this Hunter here, who else could she have called? Someone once close to her perhaps?" Yen Sid pondered aloud as he continued his research.

Back in the Forgotten Worlds…

Sora was flying along through space when he came to a sudden stop. He stood upright on his glider and turned to look over his shoulder.

"Nixe?" He asked, confused, but saw nothing there but more space. He then shook his head, continuing his flight through the stars…

End Chapter 40

Who is this mysterious attacker? Why were they looking for Xenix? How are they connected to her? These are questions that will be answered…

…just not in this story.

This fight was essentially the optional boss-fight to sort of preview the main boss of the next game. Like Xemnas was in KH1 Final Mix, Terra's armor in KH2 FM, Young Xehanort in Birth by Sleep, etcetera. In this case though, the "boss" is for the story after the next one.