Disclaimer: I own neither Sword Art Online nor Katekyo Hitman Reborn. I'm only doing it for fun.

Author's note: Hi there! This is my first fanfiction, hope you will enjoy it. English is not my first language, so please excuse me for any grammatical error I made, I would happily correct it if you tell me about it.

Chapter 1: A world of swords

Nana

'Please, let this nightmare end. Please, wake up Tsu-kun.' thought Sawada Nana, furiously blinking back the tears that wouldn't stop falling since she heard the news. Since she was told that her son may never wake up.

The day started out so well, so perfect. It shouldn't have ended this way.

Iemetsu-kun was finally able to home from his busy job in the Antarctic and he brought gifts with himself. She got a very nice dress - that romantic man - and Tsu-kun got a game called Sword Art Online.

The joy on her darling son's face was so sweet she couldn't help but admire it According to her boys the game was for something called NerveGear which her husband also bought and was able to make a game as lifelike as possible.

Her son couldn't sit still wanting to play with his game, so because it was Saturday and Tsu-kun was really trying hard at school lately, she allowed him to play while she and Iemitsu went out for lunch. Nana would later learn what a grave mistake it became.

At the end of their date, Iemitsu got an urgent phone call. Something happened at work because he needed to go back as soon as he could. The housewife accepted his apology, happy even for this little time with her husband. So from the restaurant, she headed home, while he went to the Airport.

It was during the trip back home, that she began to hear whispers about a tragedy. About some game, thousands of kids imprisoned, hundreds of dead already. A pit began to form in her stomach and dread weighed down her limbs as she saw the police at her home.

She could only sob desperately as she was told the news. "Tsu-kun.".

-0-

After that everything blurred together. She recalled collapsing upon seeing the motionless form of her son -her 11-year-old son- with that cursed helmet on, holding his limp hand in the ambulance through his trip to the hospital and trying to hold it together with other distraught parents especially when one of the kid's helmet ended the life of the poor girl who was wearing it.

All Nana could think amongst painful sobs, that she couldn't consider a world without her little Tsu-kun's shy smiles.

-0-

Natsu

Tsuna couldn't breathe. It wasn't supposed to happen. He should be eating dinner with Mom, maybe with his father, not having a panic attack in the middle of this...this Death Game.

The almost twelve-year-old was small for his age, had spiky brown hair standing in every direction above large doe eyes. He was easy to mistake for a girl due to his effeminate build.

Tsuna or Natsu in this world wore an orange-colored version of the basic starting gear with a one-handed sword strapped across his back.

Natsu almost shrieked and most definitely jumped when a large hand reassuringly gripped his shoulder. Looking at the man standing beside him, the boy slightly relaxed. Agil cut a very imposing figure. He was of Afro-American descent, two meter tall and broad-shouldered, bald and had a goatee. Despite this, the gentle look on his face was able to calm Natsu down slightly.

"Do you feel better, Natsu-kun?"

With a small smile, the young swordsman nodded while he began to think about the events that led him here.

-0-

Sawada Tsunayoshi better known as Dame-Tsuna couldn't wipe the smile off his face. This was the best day of his life. His father finally came home. through he was happy because Mom was happy, and gave him what he always wanted. Sword art online, the very first Vrmmorpg game ever. To top it all today was the game's opening.

Tsuna always liked games, RPGs most of all because it allowed him to get away from his Dame self. With great enthusiasm, he logged in and hastily created his character Natsu.

He made his avatar with very few modifications to his original looks. Natsu was taller, looking more like a 14-year-old than Tsuna's 11, had blonde hair and orange-colored eyes.

After character creation, he began to finally play and Natsu was enamored by the game in an instant. When he finished marveling at how real everything looked, he set out to explore this world of swords.

After leaving Starting City, he soon joined a party of two players.

Agil, an older man with black skin and black styled in a mohawk, who was a starting two-handed axe user, invited Natsu with a smile filled with excitement. According to him, he looked so lost after getting to the field, he felt he should help Natsu get through the first hurdles of familiarizing himself with the game.

The other player was called Buzz. The slightly older looking boy had blue colored hair which was pulled into a ponytail. The spear-wielding teen was a former beta tester who knew Agil from real life and with a wry smile, after prompted by Agil, offered Natsu to help with the basics.

The younger boy was quick to accept the help, more to play with other people than anything. He soon found out, he had a surprisingly good sense when it came to combat. The clumsiness that followed him to every aspect of his life was strangely absent. He still tripped from time to time, but when he began fighting his moves became clearer, more confident and he gained a sort of sixth sense when it came to anticipating his opponent's movements. Natsu still made some mistakes, panicked a few times but he was always helped out by Agil or Buzz.

Everything went so well Natsu hasn't thought of logging out, till Agil mentioned the time, near 5 pm. Before he could react to this, all three players were engulfed by a bright light.

Right after this, the world changed forever.

-0-

The party of players found themselves in the largest square in Starting City along with what looked like most of the players. Natsu and Agil looked around confused, while Buzz was checking something on his menu, with an increasing frown on his face.

For a few seconds, everyone just looked around without a word.

Then a few mumbles and mutters could be heard here and there; it started to get louder.

"What's happening?"

"Can we log out now?"

"Can't they take care of it quickly?"

Comments like these could be heard from time to time.

As the players started to get more annoyed, shouts like "Is this a joke?" and "Get the hell out here, GMs!" could be heard.

Natsu was getting worried, feeling something was very wrong, when he had the sudden urge to look up. The bottom surface of the second floor, one hundred meters up in the air was checkered in red.

When he looked closely, he could make out that they were made up of two phrases crisscrossing each other. The word that was written in red was Warning and System Announcement.

Agil, let out a huff of relief seeing this.

"Looks like the GM's about to explain what's the problem. About time."

However, the look on Buzz's face said he was not convinced. To be honest Natsu also felt unsure.

What happened after that told them they were right.

From the middle of the pattern, a liquid similar to blood started oozing down slowly. It came down at a rate that almost emphasized how viscid it was, but it didn't fall; instead, it started morphing into another shape.

What appeared was a twenty-meter tall man with a hooded robe draped around him.

No, that wasn't exactly right. From where they were looking, they could easily see into the hood—there was no face. It was empty.

They could clearly see the inner cloth and the green embroidery inside the hood. It was the same inside the robe; all they could see inside the rim were shadows.

"That's the robe of a GM but what's with the freaky setup?"

Buzz began to look even more agitated, even Agil lost his newfound relief. Natsu bit his lips, if the intention was to frighten them, it was working very well.

The right hand of the robe moved, silencing the numerous whispers that broke out.

A pure white glove appeared from the folds of the long sleeve. But this sleeve, like the rest of the robe, wasn't connected to any sort of body.

Then the left arm slowly lifted upwards, too. Then with its two empty gloves spread out in front of ten thousand players, the faceless person opened his mouth—no, it felt like it did. Then a low and calm voice of a male resonated from high up in the air.

"Players, I welcome you all to my world."

Natsu thought the words held a strange weight, but couldn't voice his it. The anonymous red robe lowered its two arms and continued talking.

"My name is Kayaba Akihiko. Right now, I am the only person who can control this world."

Kayaba Akihiko. That name sent a jolt of shock through his spine. The creator of FullDive technology which enabled this game and the game itself. Even Natsu knew about him enough to realize the weight his word carried. But what is he talking about?

"I think that most of you have discovered the fact that the log out button has disappeared from the main menu. This is not a bug; it is all part of Sword Art Online's system.'"

"Part of...the system?"

Natsu muttered; his voice breaking up. He couldn't comprehend it. The announcement continued in its low voice as if to cover the sound.

"Until you get to the top of this castle, you cannot log out of your own free will."

Then the next thing that Kayaba said dashed any hope the players held.

"...also, the discontinuation or dismantling of the Nerve Gear from the outside is strictly forbidden. If these things are attempted..."

A moment of silence.

The silence of ten thousand people was overwhelming. The next words came slowly.

"The signal sensors in your Nerve Gear will emit a strong electromagnetic pulse, destroying your brain and stopping all of your basic functions."

Natsu couldn't understand the significance of every word but the face Agil made, cleared away any confusion.

Any user that turned the Nerve Gear off or unlocked the clasp and took it off would be killed. That is what Kayaba had just stated.

"It-it's just a prank, right? That's no way that's true." stated Natsu, hoping the older men agree with his words.

But Buzz stood still teeth clenching as he stared at the form of Kayaba. Ad if against his will he began to speak, destroying the last of Natsu's hopes.

"Theoretically it could be used for that, the NerveGear is basically a microwave."

Terror gripped the young boy's heart at the confirmation, he almost missed the next announcement.

"To be a little more specific, dislocation from an outside source of electricity for ten minutes, being cut off from the system for more than two hours, or any attempt to unlock, dismantle, or destroy the Nerve Gear. If any of these conditions are met, the brain destruction sequence will start. These conditions have been made known to the government and the public through mass media in the outside world."

"On that note, there have been several cases where the relatives or friends have ignored the warnings and tried to forcefully get rid of the Nerve Gear. The result—'" The metallic voice took a short breath here. "—regretfully 213 players have already exited this game, and the real world forever."

Agil and Buzz opened their mouths to shout denials, but nothing came out. Natsu wanted to do the same, but part of him already accepted the truth. That was no joke, no opening ceremony, rather it was the new reality they had to live in.

If what Kayaba said was true, over 200 people have already died up until now?

"'Players, there is no need to worry about the bodies that you have left on the other side. As of this moment, all TV, radio, and internet media are all repeatedly reporting this situation, including the fact that there have been numerous deaths. The danger of having your Nerve Gear taken off has already all but disappeared. In a moment, using the two hours I have given, all of you will be transported to hospitals or similar institutes and be given the best treatment. So you can relax...and concentrate on beating the game.'"

"What...?"

Then, at last, Buzz started shouting violently.

"What are you saying!? Beat the game!? You want us to play around in a situation like this!?"

Then Kayaba Akihiko started announcing silently with his monotonous voice.

"But I ask of you all to understand that Sword Art Online is no longer a simple game. It is a second reality...from now on, any form of revival in the game will no longer work. The moment that your HP reaches 0, your avatar will be gone forever, and at the same time—"

Natsu could guess what he was going to say all too clearly.

"Your brain will be destroyed by the Nerve Gear."

Natsu couldn't see the point, why would Kayaba Akihiko do this? If you die you die for real, you can't even stop playing. Who in their right mind would leave the city with those conditions?

Then as if answering those unspoken thoughts. the game's creator spoke once again.

"Players, there is only one way to be freed from this game. As I have said before, you must get to the top of Aincrad, the one-hundredth floor, and defeat the final boss that resides there. All players still alive at that time will be immediately logged out of the game. I give you all my word.'"

Ten thousand players stood in silence.

Buzz finally lost his temper, voicing the thoughts of many players.

"You want us to conquer all 100 floors!? Are you insane? The beta never reached anywhere that! That doesn't make any sense, why do this?"

Agil's face showed the same thoughts went through him and Natsu couldn't help but agree. Such an unreachable goal, such as unreasonable conditions. They didn't make sense, most were unable to accept the reality Kayaba painted before then.

Then, the red robe that had always been one step ahead of us swept its right glove and started speaking with a voice void of all emotion.

"Then I will show you evidence that this is your only reality. In your inventories, there will be a gift from me. Please confirm this."

Natsu pressed the item button on the menu that had just appeared and the item was there, at the top of his belongings list.

The name of the item—hand mirror.

Frowning in confusion, he tapped on the name

and pressed the "make into object" button. Immediately afterward, there was a twinkling sound effect and a small rectangular mirror

appeared.

Natsu reached out and grabbed it. but nothing happened. Looking to the side he saw Agil and Buzz also staring at their mirrors.

Then suddenly every avatar around them including their own was surrounded by blue light, similar to the effect of teleportation. When it disappeared everything looked the same except one thing - the players.

Agil was as tall as ever, but he lost the mohawk and replaced it with a bald head. His features took a more gentle look, along with a short beard shaping his face.

While Agil was easy to recognize despite the change in his avatar, with Buzz it was much more difficult to find similarities. His blue hair was replaced with greying, brown, his eyes sporting a green coloring now. The previously 18-year-old looking man was suddenly around the age of 30. He looked foreign, European if he has to make a guess.

While he tried to connect the people before him with those he partied with earlier today, the two older looked at each other and recognized the other easily due to their friendship in real life. Then they brought their shocked, disbelieving eyes towards him.

Now that Natsu thought about it, the two looked taller, no everything looked taller as if he. became...a foot shorter in an instant.

"Natsu...-kun?" called out Agil uncertainty.

Looking at the hand mirror confirmed his suspicions. The 14-year-old blonde Natsu was replaced by the 11-year-old Tsuna. Complete with fluffy, gravity-defying brown hair and equally brown eyes. His quiet confidence. which helped to keep his calm in the face of what's happening disappeared without any trace, because Tsuna not strong like Natsu, Tsuna couldn't face this madness.

His internal worrying was put to a halt, when Agil reassuringly gripped his shoulder, directing a calming smile to the young boy. He ignored Buzz's theories about how the game knew their face. height and the like, while he came to grips with this sudden dose of reality.

As ten thousand players struggled to come to terms that this was not a joke, not a prank, there was one question that stood out in everyone's mind. Why?

A few seconds later a voice, sounding almost solemn, sounded from the blood-red sky.

"You will all most probably be wondering 'why.' Why am I—the creator of both the Nerve Gear and SAO, Kayaba Akihiko—doing something like this? Is this a sort of terrorist attack? Is he doing this to ransom us?'"

It was then that Kayaba's voice, which had been emotionless up to now, seemed to show some signs of emotion.

"None of these is the reason I am doing this. Not only that but now for me, there is no longer a reason or a purpose in doing this. The reason is because...this situation itself was my purpose in doing this. To create and watch this world is the only reason I have created the Nerve Gear and SAO. And now, everything has been realized.'"

Then after a short break, Kayaba's voice, now emotionless again, sounded.

"...now I have finished the official tutorial for Sword Art Online. Best of luck players."

The huge robe rose soundlessly and started sinking, hood first, into the system message that covered the sky as if melting.

Its shoulders, then its chest, then its two arms and legs merged into the red surface, and then a final red stain spread briefly. Right afterward, the system message that had covered the sky disappeared as suddenly as it appeared.

The game had returned to its normal state, apart from the fact that a couple of rules had been changed.

As a pandemonium of panicked cries ensured, Natsu felt himself led into a nearby alley by Agil. Looking up he caught Buzz and Agil arguing about what to do.

"The next town is near here, we can have an easier time to level and gear up. Leave the kid here in the inn and let's go while we are ahead of others." Buzz's voice was rougher, older than before. He was looking in the directory of the rest of the players, looking anxious to leave.

"What about other players? They will need help to survive!"

Agil's voice sounded far calmer than what the situation demanded, but it helped ground Natsu's thoughts. Forcing himself not to focus on the thoughts of being trapped - of not seeing Mama ever again -, Natsu quickly went through what to do. What Natsu would as opposed to Dame-Tsuna.

"I'm going with you" both men started to object, but he continued talking before he lost his nerve. " I won't sit here, waiting to be rescued. You both told me I was natural at fighting, I won't slow you down, I promise!"

The two men looked at each other and after a silent exchange seemed resigned to the fact that the young boy would follow them.

-0-

After that, the three of them left behind the City of Beginnings with Buzz leading them through a safer route. During that time they saw a black-haired young man ahead of them, but soon lost sight of him.

Before long they arrived at the village, Natsu's eyes curiously burning with an orange light with his resolution and silent promise.

'I'll survive this world and I'll return home. I promise this on my dying will.'