Summary: Since she was absorbed by him, Roxas never forgot about Xion. Enraged by the way he and Xion was used by Xemnas, Roxas sets out to destroy his former leader and free Kingdom Hearts, keeping his promise to his friend to free the hearts she had captured.

Disclaimer: I don't own anything related to Kingdom Hearts. Those rights belongs solely to Mr Tetsuyo Nomura, Square Enix and Disney.

The Avenger

Chapter One: The Neoshadows

The rain was pouring down over The World that Never Was. Puddles and puddles of water gathered on the ground, everywhere on the asphalt in the world of the Nobodies. The darkness and silence laid heavy over the street, save for the sound of the falling raindrops against the mirror of water that was covering the ground. Then, without warning, a portal to a Corridor of Darkness appeared in a distant alley. However, it was only open for a short good second before the corridor's only passenger had stepped out into the rain and the portal closed behind him.

The newcomer, the only living being in the street as of this moment, was wearing a coat entierly in black, his hood covering his face and only revealing his chin, mouth and strands of long blonde hair. For a moment, he just stood there, as if he was taking in the surroundings, the view of his former home. It hadn't been long since this world had been the only home he had known, yet now it all felt empty. He had been here so many times before, walked these streets... but it all felt different now. The relief he used to feel whenever he returned here from a mission was nowhere to be found and all he felt and saw were potential threats.

After the short moment of reverie, he looked up towards the open skies. It was clouded, covered in black clouds that were the reason for the downpour. Then again, those clouds had always been hanging there. Maybe they were just an illustration? They were always hanging there, keeping sunrays or light from ever reaching down to the earth. So then again, the clouds probably had nothing to do with the downpour after all.

'Xion... Are you crying?' Roxas thought as he held out a hand to watch the raindrops gather in the middle of his open palm, floating around on the strong leathered gloves. His coat and overall leather dress were water resistant, so he didn't even feel the moisture or liquid, other than on his cheeks that weren't covered by anything.

Funny... why was he expecting to feel anything at all? He was a nobody. Nobodies weren't supposed to feel anything. Any feelings they could make out were just illusions, lies... because they didn't have "hearts". But Roxas knew. He knew now, he had a heart. This pain he was feeling, the sadness and despair over the loss of his best friend... they were real. They weren't just mere imaginations. It tore at his heart and made his chest feel like someone had ripped a hole straight through it.

He clenched his fist in anger. Just thinking about it made his blood boil. Why did it have to happen? How did it come to this? They could've run away, they could've gone into hiding. He would gladly have done anything... ANYTHING to keep her safe. He didn't care if The Organisation or even the entire UNIVERSE came after them, he would've thought of something. He would've kept running forever if he had to.

It was all Xemnas fault. He orchestrated all this... set it up. He had been the one who brainwashed Xion into fighting him. He had been the one who set them on a collision course.

Roxas grit his teeth and began to walk down the street. He should've seen it coming. Xemnas had tried to have him and Xion fight before, he should've guessed that the "Superior of the In-Between" would keep trying until he succeeded. As powerhungry as that man was, he wouldn't settle for a failed experiment or a failed operation. Once he set his mind on something, he didn't stop until he was either annihilated or succeeded in his quest. And sadly, no one had managed to annihilate him. At least, not yet anyway.

As his leathered boots left footprints and ripples in the puddles in the street, Roxas became aware that something else was also emerging from his steps. Dark spots began to appear behind him and looking further over his shoulder, he could see that they had been following him ever since he left the alley. The street behind him was crawling with black, semi-humanoid creatures. The heartless had found one of the Keyblade's chosen.

Sighing under his breath, Roxas held out his hands in front of him. He concentrated and felt that all too familiar tingle in his hands. Not a second later, two Keyshaped swords appeared in his grip: his own Kingdom Key, as well as Xion's. For a moment, he stopped and looked at the Keyblade in his left hand, the one that felt different from his usual weapon. This was the power gifted to him, the power his best friend had bestowed upon him in her last moments. And he was going to put it to good use. He had made a promise to Xion to stop Xemnas, and he would do it with her weapon. He would keep his Oath.

As he thought it, the Kingdom Key was covered by an intense glow and Roxas felt a warmth spread from his palm and up his arm, as if Xion herself was trying to say thank you. The Keyblade began to change until it was no longer recognizeable as the Kingdom Key. It now had a light blue color, and an almost star-like design at the tip of its blade, rather than the traditional Keyshape. Oathkeeper. That was what this new weapon should be called.

He then turned to his other Keyblade, the one that was originally his. This weapon had been the cause of many hearts being released. It had its blade responsible for both many good and many bad deeds. But soon, all that would be forgotten, and he would be able to turn over a new page. Everything bad that his Keyblade had caused would be undone, and the memories would fade... into Oblivion.

With that, this Keyblade as well was covered by a strong light, changing into a shape more similar to Oathkeeper, but colored black, rather than the colorful blue, orange and yellow that graced its counterpart. Oblivion, that was its name.

With his new weapons at the ready, Roxas looked up. The swarm of Heartless, Neoshadows to be exact, had grown to an insane number and they were crawling everywhere within sight. Roxas couldn't even make out the asphalt of the street for all the Neoshadows. He had never seen this many heartless before, yet he felt no fear nor doubt. He knew that with Xion's help, he would make it through this. No matter what, he was going to keep his promise and if that meant going through this insane swarm of heartless, so be it.

Spinning his Keyblades in the air in front of him as a sign of challenge, one of the Neoshadows released itself from the crowd and flew straight at him. Barely had it entered his range before Roxas spun in place and had Oblivion tear straight through the heartless. The transformation seemingly hadn't just changed his weapon's appearence. It seemingly had increased the cutting edge of it, and boosted its overall power. The blade tore through the heartless as if the creature had been made of butter.

However, he didn't have time to marvel over his increased strenght. Seconds later, three Neoshadows were flying at him and forced him to raise Oathkeeper for protection. One of the Neoshadows impacted its claw on Oathkeepers blade and was stopped in its descent. Roxas mustered up all his strenght and pushed the heartless backwards, straight into one of its fellow Neoshadows. The two heartless were thrown back, but the third was still closing in on him and fast. Not waiting to find out what those razor-sharp claws felt like, Roxas jumped backwards and summersaulted, kicking the advancing Neoshadow in the process.

He barely had enough time to land before another wave of heartless came sweeping down over him. Spinning Oathkeeper in his hand, Roxas twisted his body into a spinn, slashing through the wave of heartless with Oathkeeper in a reverse grip. Strangely enough, wielding his Keyblade in a reverse grip didn't feel foreign to him. Then again, maybe it had something to do with his connection to so many different people. Sora for one, and then there was Xion. Maybe one of them had used a reverse grip at some point. That would explain why it felt so natural.

Not stopping to think about it, Roxas decided to take the initiative this time and darted forward, slashing Oblivion through a few heartless that had been about to rush him. He slammed the black Keyblade into the ground and used it to jump high into the air, once more summersaulting so he was upside down. When he was straight upside down, he threw Oathkeeper like a boomerang. The spinning Keyblade tore through the horde of black creatures in an arc, making its way back to its owner just as Roxas landed on his feet.

Just as he landed, he spun on his feet again, sending his Keyblades flying in a circular motion. The two weapons soared through the air, orbitting around him and cutting through several of the heartless that were closest to him. After a moment, he called Oblivion back to his hand as a stray neoshadow managed to avoid the orbitting blades and rush him. Blocking the attack, Roxas kicked the neoshadow in the torso to gain some distance before he slashed it in half with his Keyblade.

Calling Oathkeeper back as well, Roxas dashed through the crowd of heartless, spinning his keyblades like razors in front of him as he cleared a path towards Memory Skyscraper. When he reached the stairs in front of the tall building, he jumped high into the air, twisting in mid air to avoid being slashed by a pair of neoshadows that had jumped after him, and landed on top of the stairs. Not a second later, he spun around and slashed Oathkeeper across the pair of heartless that had followed him.

For a moment, no heartless made an attempt to attack him, giving Roxas some space to breath. He was panting slightly from the strain of keeping two keyblades materialized. Endurance for extended battles had never been his fortitude and wielding dual keyblades, the strain was twice as high as it usually was. And what was worse, it didn't appear as if the crowd of heartless had been cut down to size in the slightest. For every neoshadow he cut down, two new once emerged to take its place. If this didn't change soon, this battle would be going on forever.

"Don't give up, Roxas!"

Roxas startled as the voice echoed through his head. That voice... Was it Xion? Was she still alive, somewhere deep inside him? Or was it just a memory or an imagination?

Frozen in his tracks for a second, Roxas didn't notice the neoshadows that were approaching from above him, from the upper part of the Memory Skyscraper. He just heard the swisch as the heartless sailed through the air and had just enough time to look up to see the black creatures swoop down towards him. He tried to raise his Keyblade to block the strike, but couldn't get it up in time.

A searing pain erupted from his shoulder where the neoshadow's razor-sharp claws hit him. He stumbled back and grit his teeth, swinging his uninjured arm, the one holding Oblivion, at the offending heartless, cleaving it in two with a horizontal slash.

Jumping back to avoid another heartless, Roxas cursed under his breath as more heartless leaped at him. Swinging Oblivion in a wide arch, he tried to flex his left arm but just moving it caused the pain to increase. He could feel a warmth spreading from his shoulder and knew that he was bleeding from the wound. He looked around frantically, trying despreately to find some shelter or spot where he could catch a breath and perform a Curaga spell, but everywhere he looked he could only see heartless, heartless and more heartless.

'Dammit! This is NOT good!' he thought as he summersaulted through the air, vanishing Oathkeeper for the time being so that he could focus on using just Oblivion, as his left arm had become a hindrance, rather than an advantage.

He landed in the middle of the street, in a spot that for the time being was relatively heartless-free. However, as soon as he had landed, a neoshadow released itself fromt he crowd and flew at him. Roxas ducked under its attack and slashed Oblivion in an arch over his head, cutting through his offender as he held his left arm close to his body.

As more heartless flew at him, Roxas did his best to hold them at bay using just one keyblade. He ducked, slashed, jumped dodged and rolled out of the way from his attackers, but the more heartless he cut down, the more came at him.

Scouting the scene for a possible sanctuary, if only temporarily, a lightning bolt cut through through the clouds, illuminating the entire street. When it did, the heartless came to a temporary stop and Roxas got a good 3 seconds to catch his breath. However, 3 seconds was all he needed. Raising his keyblade into the air, Roxas allowed his power to flow through it, before it streamed back into him.

"Heal!" he shouted at the top of his lungs, feeling how the wound on his shoulder closed through the power of his Curaga spell.

He knew that he would still need to look it up later, as Curaga was only a temporary fix, but it would do for now. He had gotten other things to think about. When he had raised his keyblade to perform the spell, in the moment of light when the lightning bolt streaked across the sky, he had noticed a figure standing atop Memory Skyscraper. The figure in question was dressed in a similar attire to himself, but had his hood pulled down, showing off a face that had a blindfold covering his eyes, with long white hair that was flowing in the wind.

'Riku...'

Without a second thought, Roxas summoned his second keyblade and rushed towards Memory Skyscraper again. Spinning his keyblades in front of him, he quickly cut his way through the horde of neoshadows. As soon as he reached the stairs of the Skyscraper, he leaped onto its wall and rushed upwards, avoiding any confrontation best he could as to not lose his momentum.

Seeing Roxas rushing up towards him, Riku took one step towards the edge before jumping off, diving towards the ground. Roxas, not doubting for a second that Riku would survive the fall, tossed Oblivion towards him. As the Keyblade sailed through the air, it cut through some unfortunate Neoshadows that got in its way, before it finally met Riku half way. The white haired boy grabbed the Keyblade's hilt and continued his dive towards the ground.

When the two of them met half way, they locked eyes for a brief moment. Even though Riku's eyes were covered by his blindfold, Roxas could still tell that Riku was not too happy to see him, but for now they had a common goal to accomplish.

Roxas landed atop the same screen where Riku had been standing just a moment ago and stopped for a second to catch his breath. This battle was tiring and keeping two Keyblades materialized at the same time wore him down faster than he had thought. It was standing to reason that it would be harder to use two Keyblades than it was to use one, but he had never guessed it would drain him this much. Add in that Curaga spell and he knew that he was going to be running on his reserve energy by the time he and Riku had dispatched of all these Neoshadows.

'Don't give up Roxas!'

Hearing that voice again... the voice that he had thought he'd never hear ever again, Roxas breath caught in his throat. Xion... So she was alive, somehow! The first time, he had thought that he might have imagined it, but this time he was sure that he had heard her voice calling out to him!

'I'll lend you strenght, just don't give up Roxas! You're almost there!'

As she, or at least her voice, said it, Roxas felt a warmth spread through his chest, bringing back some of the energy he was sure he had lost. Gripping Oathkeeper tighter in his hand, Roxas turned around to look down towards the square, where Riku was currently doing his best to dispatch of the Neoshadows. For a moment, he just stood there, his mind slowly processing the fact that his best friend was still alive, somewhere deep inside of him. Then, he took a deep breath and jumped of the skyscraper to help Riku.

'Thanks Xion.'

A/N: This story will be very short, and a lot of it might be taken from "Another Side, Another Story", but hopefully it will be enjoyable for those KH fans out there who liked Roxas and, like me, felt he deserved better than what he got!