Yay~! My very first fanfic :3
To clarify, Semi-AU. There's still Vongola and all the Guardians are the same except for Tsuna. Tsuna has no connection to the Vongola or even the Sawadas.
In comparison to the original story it's kinda curved. The beginning is almost the same and it slowly strays off from there until it's completely different.

All27. As much as I love R27 and Fong27, they and any other Arcobaleno pairing will sadly not be in here! I couldn't think of a good reason of why the curse would be broken. If in the Representative Battle of the Rainbow arc or any future arc has the breaks the curse, I might have Arcobaleno27, but I doubt the manga will ever do that.

Disclaimer: Katekyo Hitman Reborn belongs to Akira Amano. I wish I owned it x|

Yeah...Well this is kind of a prologue-ish chapter so we'll get more into the characters later ;)

Full summary:

Experiment #027 of the Estraneo family was released by Rokudo Mukuro along with Ken Joshima and Chikusa Kakimoto. With nowhere else to go, he joins them on their mission to destroy the mafia. When Chrome is called upon to take the place of Mukuro in the Battle for the Mist Ring, Tsuna accompanies them and meets Hanatsu, the future Vongola Decimo and his Guardians. With his burning passion against the mafia, he makes new acquaintances and slowly, his opinion of them changes. Starts in the middle of the Varia arc. Semi-AU and slight All27, main 6927.

Ken and Chikusa led the way into the school's gymnasium. For once, Ken was acting serious and refrained from making to much noise. The moment they were seen by the Vongola guardians the air became thick with fear, curiosity, and frustration.

Gokudera tensed, preparing to attack the new arrivals.

"Y-you can't be saying the Guardian of the Mist Ring is..."

"Yeah. For them to bring him, that's..." Yamamoto had no trace of his usual smile on his face. The incident at Kokuyo had given them all a large amount of distrust for the two.

"As if...The Guardian of the Mist Ring is...Rokudo Mukuro?!" The future Vongola Decimo was surprised. Hadn't he beaten him? Wasn't he in prison?
In response Ken and Chikusa only seemed...ashamed? They looked at the ground and moved out of the way for whoever was behind them to move forward.

"Negative." Two shadows moved into the light, making the their faces visible. The first one was a short brunette boy with spiky, gravity-defying hair. His brown eyes were wide but filled with a strong, burning determination. Reborn eyed the boy. He had seen no files on such a person being connected to Mukuro before and he had not been present during the time Mukuro was in Kokuyo.

The next person to enter was the one who had talked, a girl only a few centimeters shorter then the boy.
Her purple hair was pulled into a pineapple-shape that reminded everyone of Mukuro. Her one large purple eye was calculating, but had a hint of fear in them as well. The other eye was covered with an eye patch with an interesting skull design.

"Huh?" Hanatsu's(1) eyes widened. He didn't recognize either of the two. If it wasn't Rokudo Mukuro, then who was his Mist Ring Guardian?

"My name is Chrome. Chrome Dokuro." The girl spoke again and walked towards group of Vongola Guardians.

"Who's the girl with the extremely weird name?" Ryohei inquired.
"Someone you know Natsu?" Yamamoto was the next one to speak.

"Ehh...Hey, Guardian of the Mist Ring...This girl isn't Mukuro Rokudo right?" Hanatsu wanted to trust his new Guardian. Aren't they supposed to be family?
Ken and Chikusa displayed small signs of annoyance, but at what no one could tell. The mystery boy only stood between the two watching Chrome and the Vongola Guardians for their reactions.

"Don't be fooled Juudaime! That's Mukuro! He's just possessing her! He's the kind of man that does whatever it takes to accomplish his objective!"
The Guardians were once again reminded of when they themselves had been possessed by Mukuro. While possessed by him they had been forced to battle Hanatsu.

"You don't believe me?" Chrome seemed distraught at the distrust that was directed at her.
"Of course not! Juudaime, look at her weapon! She's just hiding the strange eye with an eye-patch. This is definitely..."

Suddenly Hanatsu perked up. His "Vongola" intuition was nagging at him. "This isn't Rokudo Mukuro." he said firmly.

Gokudera turned around from his position in front of Hanatsu, surprised. "R-really?"
"Well, it's just a hunch..." Hanatsu was surprised by how he was so sure that his intuition was correct.

Chrome stepped closer to Hanatsu. "You're defending me! Thank you." The pineapple-haired girl grasped his hand firmly, her eye filled with overflowing resolve.(2)

"What are you doing?!" Gokudera immediately became protective of his boss.
"Maa, maa." Yamamoto grabbed him from behind and held him in place to stop him from attacking the new Mist Guardian. The rest of the people in the gym were only confused(Ryohei), curious(Basil), bored(Varia), and passive(Kokuyo). Gokudera continued to struggle in Yamamoto's grip and shout at Chrome and Yamamoto while the former was oblivious as to what she had done to warrant such treatment.

The Varia talked amongst themselves on their opinion of the "show" taking place in front of them. Xanxus sat in his signature chair, obviously thinking of how weak the trash in front of him was. Mammon merely observed his/her(3) opponent, finding her quite an interesting character as Phantasma prepared for the upcoming fight.

The Guardians and the Kokuyo gang then began to argue on whether to accept the new Guardian. Ken and Chikusa were offended that Gokudera refused to acknowledge their Guardian. The mystery boy continued to observe. The argument continued until Hanatsu settled it and the Battle started.

The matching Cervello explained the basic rules of the upcoming battle. The Vongola and Kokuyo stood together inside a barrier on one side of the room and the Varia in the other, each equipped with an infrared sensor to stop any interference from the surrounding spectators.

When the battle finally started, the two Mist Guardians threw illusion after illusion at each other. While both affected the unprepared observers, Chrome's illusions were unable to harm the Varia member.

Chrome however, was able to fool Mammon and escape from his/her illusions unharmed. Having used an illusion of her own to make a basket full of basketballs appear and act in her image. Ken smiled triumphantly as Chikusa and the other boy watched the fight silently.
The Vongola Guardians were surprised and confused. Reborn proceeded to explain the battle of illusions taking place before them.

As Hanatsu continued his internal debate on whether to trust Chrome or not, Mammon suddenly dropped chains from beneath his/her cloak.

"Let's go, Phantasma." The frog upon his/her head started to crack, and from the shell emerged a sickly yellow and white snake. The snake then bit it's own tail, resembling an ouroboros.

Two triangular purple tattoos appeared on Mammon's cheeks and he/she revealed his/her indigo pacifier. Phantasma floated above Mammon's head as he/she ascended to the air.

Reborn and Colonello recognized the strange infant, reintroducing him/her as Viper, the Mist Arcobaleno. Chrome was visibly distraught by this, knowing how strong the Arcobaleno were. The Varia(mostly Bel and Levi) stood by anxiously waiting for Mammon's true power to be released.

"This is bad. Your average illusionist won't have a chance against that nut, kora." Colonello was worried. Viper was a talented illusionist, if not the most powerful.

"Don't underestimate her Colonello. Chrome isn't your average illusionist." Reborn reassured him.

"I don't care who you are! I won't lose!"

Since her illusions had little affect on Mammon, Chrome began to use the trident that she had been carrying. Mammon easily evaded all of these attacks, using Phantasma to fly.

"It's futile to wave that stick around when you can't fly. Such an earnest attack." Mammon taunted Chrome.

On the ground Chrome summoned four large snakes out of nowhere and they wrapped themselves around the Arcobaleno.
"What?! It's not an illusion?" The snakes were completely real.

The Vongola spectators watched in amazement. And wasn't that the same technique that Mukuro had used? Hanatsu was confused because Chrome resembled Mukuro so much, but his intuition was telling him they were separate people.

Meanwhile, Mammon's indigo pacifier glowed brighter and released enough power to free him/herself from the snakes.
"I suppose I should get around to releasing my power too. I can take my time investigating your identity afterwards."

In response, Chrome twirled her trident around before bringing the base to the floor of the gymnasium. Red, hot spots appeared on the ground before erupting and turning into miniature volcanoes spewing lava. One such "volcano" appeared directly underneath Mammon, making a direct hit.

"It won't be good enough." Reborn said.

Mammon easily moved out of the lava unharmed.
"Your illusions are certainly top-notch. I'd undoubtebly be burned to a crisp if I believed them. But that means your weakness also lies in illusions!"

The lava suddenly turned to ice and the whole gym appeared to now be frozen.
Slowly, the ice crept upon Chrome until her legs completely covered in a thick layer of ice.

All of the Kokuyo members appeared slightly distraught but continued watching the fight as they and the other spectators shivered from the cold.

"How do you like the abominable power of the Arcobaleno? Now why don't we reveal your real identity?"

Mammon made a gesture with his/her hand and Chrome was knocked back against one of the ice pillars. The ice disappeared leaving only an inconspicuous and normal looking gym.

Chrome lunged towards her trident that had fallen out of her grasp and onto the floor.

"It appears that weapon is especially valuable to you. Heh." Chrome's eyes widened as she realized what he/she was implying.

"N-no..." Mammon merely held his/her hand in front of him/her and made a fist.

"No!" But it was too late. She could only watch as the trident that she had been holding shattered to pieces.

When the trident broke Chrome collapsed to the floor, looking pale and sickly.

Where her stomach should be, started to cave in, and she struggled to breath.

"M-Mukuro...sama..."

"What's happening? Who is this girl?" So Mammon didn't know what was going on either.

"Mukuro-sama..."

"It's hard to believe, but she's able to survive because of illusionary organs." Mammon explained after investigation.

The Kokuyo gang went on alert, wishing they weren't stuck in the barrier. Even the unknown boy was clenching his fists, glaring at Mammon.

"I wanted to help...Mukuro-sama..."

Hanatsu suppressed a shiver. Something was wrong, very wrong. It almost felt like...him?
Although no one payed attention to him, the brunette who had entered with the Kokuyo acted anxious. He could feel his presence. So close, oh so close.

Not sensing him the Varia were disappointed that the battle had not lasted longer.

But then, smoke was released from the Chrome's sleeves as she laid on the floor, almost dead.

Mammon scoffed that it was her futile attempt to hide her unsightly body using her illusions.

"He's coming..." Two people said at once but with two different tones, catching the attention of everyone in the gym.

The first was Hanatsu. He was shaking whilst holding his head, fear radiating from his figure.

The second was the unnamed brunette. Unlike Hanatsu, he seemed almost giddy. A creepy grin broke across his face as he began to laugh.

"He's coming...he's coming!"

The laughter was not comical, but instead laced with insanity. It echoed through the room and raised hairs upon many.

"It's him..." Hanatsu ignored him, to busy focusing on the intuition that was screaming at him.
Run, run, run away! It said.

"Rokudo Mukuro!" This caught everyones attention.

"Kufufu..."

Suddenly the once broken trident slammed into the ground causing cracks to appear on the floor. The cracks continued, moving towards the Mist Arcobaleno.

"What? A man's voice?" The force of the unexpected attack sent Mammon flying across the gym.

"Rather flashy...For a bunch of mafiosi..." Mukuro emerged from the mist where Chrome had once been.
The boy who had been laughing earlier seemed overjoyed at his appearance though once again, he was ignored in favor of the appearance of the pineapple haired illusionist.

"Rokudo Mukuro? I thought that name sounded familiar. Now I remember. About a month ago, someone tried to escape from Vendice Penitentiary. His name was Rokudo Mukuro."

Levi had heard of Vendice Penitentiary before. Any mafioso should know of the Iron Wall. It was said to be inescapable, and the guards invincible.

"But the attempted escape ended in failure. What's more, I heard he was confined in the basement, beyond the reach of light or sound; an even more difficult place to escape from."

Mukuro said nothing in response, only smirking slightly.

Ken was baring his teeth in frustration, remembering the attempted escape.

"That shows how limited the information network of the Vongola's glorious "special assassination squad" truly is. Here I stand before you."

"Yeah, and your a pain. Fine. But let's make one thing clear... You're just an illusion attached to the girl."

Mammon used Phantasma to float higher in the air. Then, he/she created an illusion of a blizzard to envelop the gym.
"I'm not nice enough to let myself lose to an illusion created by another illusionist." Mammon stated.

"Oya?" Mukuro looked down at his feet to see them covered in ice, similar to Chrome.

"Oya, oya..." The ice continued to grow until it encased his whole body, solidifying him.

"Now then... Shall I unmask you?" Mammon created an illusion of an iron hammer from his/her hood.

"I'll be shattering that girl's body, though." Not sounding the least bit sorry, Mammon flew forward to break the ice and Mukuro together.

But before the hammer could hit, lotus blossoms and vines wrapped themselves tightly around Mammon. The freezing illusion disappeared and Mukuro stepped out of the ice.

"Kufufufufufu... Who are you calling an illusion?" Mukuro smirked at the prone figure of Mammon that was suspended in the air by the vines.

"So powerful...It hurts..." Mammon struggled as the vines continued to tighten.

The Varia seemed to be less worried about Mammon and more curious about Mukuro.

"He's overwhelming Viper." Colonello for once, did not use 'kora!'.

"That's Tsuna's Guardian of the Mist Ring: Rokudo Mukuro." Reborn said with a hint of pride.

So if it is him, then what happened to Chrome? The Guardians wondered.

"You can't think of Chrome and Mukuro as seperate beings. Mukuro exists because of Chrome. Chrome exists because of Mukuro." Reborn 'explained'.
The Guardians only became more confused as they contemplated this new information.
Right now, it's the only way...

In the fight Mammon was still trapped by Mukuro's vines.
"How will you escape this predicament, Arcobaleno? If you dawdle too long, you'll be skewered." Mukuro warned tauntingly.

Finally, Mammon called upon his/her power and released it to escape.

"Don't get full of yourself!" Mammon yelled as he/she created multiple illusions of him/herself to confuse Mukuro.

"Too weak." Mukuro's right eye changed Paths and an indigo flame appeared around it. He proceeded to use his trident to hit all of the clones and break the illusion.

Hanatsu recognized this skill. It was the skill of combat aura, Asura.

"An illusionist capable of hand-to-hand combat? Inconceivable!" Mammon scoffed as he/she backed off from his/her opponent.
"I reject you and your Paths of Rebirth!"

"Oh?" Not sounding worried, Mukuro looked at Mammon.

"A human repeats the same life eternally! That's why I collect money!" Phantasma began to circle in place and a blinding speed and an illusion once more took over the gym and it's inhabitants.

"Hahaha! Greedy little Arcobaleno, aren't you? How amusing. But I'm just as greedy." Mukuro spun his trident and slammed it into the ground, creating illusions of fire pillars similar to Chrome's. His however, were wrapped with the same lotus vines that had nearly strangled Mammon.

Both Varia members and Vongola alike began to experience pain from the long amount of time they had spent in strong illusions. The Kokuyo fared slightly better but were affected nonetheless.

Hanatsu fell to the floor and foreign memories flooded into his mind. He saw Mukuro's body in Vendice, the attempted prison escape in which Mukuro had allowed Ken and Chikusa to leave him behind, and his own father requesting Mukuro in Chrome's body to be his Mist Guardian.

The memories stopped and Hanatsu once again found himself on the floor.

"Mukuro..."

Mammon created clones of himself that charged at Mukuro. Using his trident, Mukuro easily destroyed them all.

"You're mine." The real Mammon was behind Mukuro. Phantasma expanded and Mammon opened his/her cloak, revealing a large dark void.

The cloak swallowed Mukuro before he could react and the snake grew spikes and thrust them into part of the cloak Mukuro was.

"Mukuro-san!" Ken and Chikusa gasped while the brunette between them merely smiled, as if he knew a secret that no one else knew.

Hanatsu stared in horror, unable to believe that what had happened before his eyes was real.

Then, the strange "cloak" expanded suddenly, and one could see something struggling underneath.

"Impossible!" Mammon's cloak and Phantasma were destroyed as lotus vines ripped through them, revealing an unharmed Mukuro holding the two parts of the Vongola Mist Ring.

"Die. And be reborn."

"Impossible! Mammon is..." Levi couldn't believe it. How could Mammon be defeated?

The Vongola were amazed at the power Mukuro had. Ken and Chikusa relaxed as the brunette placed his small hands on their shoulders.

"I put these two rings together right?" Mukuro inquired.

The two Cervello turned to each other before answering.
"Yes."

"Not yet." Mammon's voice echoed through the gym.

Mukuro merely smirked as he saw the dust scattered through the room gather itself to form Mammon.

"Don't get too cocky. I was going easy on you... I have so much more power to reveal!" Mammon gasped as he/she saw that Mukuro was no longer in front of him/her. Instead he/she could hear his voice behind him/her.

"Here I thought you knew..." When Mammon turned around Mukuro was no longer there.

"When you turn an illusion back on the illusionist, it means the illusionist has completely lost control of his perceptions." Mammon gasped again. Phantasma suddenly appeared back to his normal size and began to strangle the surprised Arcobaleno.

"Stop, Phantasma!" But his/her efforts were in vain as the snake only tightened it's grip on it's owner.

"Now then... Care to show me your true power?" The illusion that was wrapped around the gym strengthened and the floor began to deteriorate faster.

"Come." The ground that Mammon had been standing on was destroyed and he/she began to fall into the red void.

Mammon tried to scream, but it came out as a strangled cry as he/she continued to fall.

"Hahaha! Well, Arcobaleno? Do you like my world?" Mukuro laughed and turned into smoke that forced it's way into Mammon's mouth.

Mammon expanded to an abnormal size and his/her body was distorted until he/she was no longer recognizable.

"Stop it, I'll die! I'll die!" Mammon begged.

"You lost for one simple reason: I was your opponent."

The black mass that had been Mammon exploded in smoke. The illusion faded and the gym returned to normal.
Mukuro gracefully landed on the floor.

"Will this do?" He opened his hand to reveal the now whole Mist Ring while looking at the Cervello.

"The Mist Ring now belongs to Chrome Dokuro. As a result, she is the victor of this match." The Cervello announced.

"Viper was..." Colonello was amazed.
"Blown to smithereens, huh?" Belphegor on the other side of the room finished, snickering at the defeat of his 'comrade'.

"No way!" Hanatsu exclaimed. "You didn't have to go that far!"

"Must you insist on showing pity for your enemies? You're a hopelessly naive man, Sawada Hanatsu. Let's just say you needn't worry."

"Eh?" Hanatsu was confused.
"The infant escaped. He saved enough strength to flee. Such a cunning Arcobaleno."

"Gola Mosca...Once the battle for the rings is over, eliminate Mammon." Xanxus spoke, a rarity in itself and he did not use "trash" or "scum", even rarer.

"You exemplify the darkness of the Mafia, Xanxus." The unknown boy flinched at this, the mafia brought back bad memories.

"Even I find your dreadful plan quite frightening." Xanxus' eyes twitched at this, wondering how he got that information at and what he would do with it.

"Fear not. I have no intention of interfering with it, since I don't happen to be a good person. But one thing: The smaller, weaker successor... I would prefer you didn't toy with him too much. Kufufu..."

Mukuro turned around and walked towards the other side of the gym.

"Mukuro-sama." Chikusa and Ken moved forward to greet him.

"Awesome! You kicked butt!" Ken shouted excitedly. The other brunette stayed quiet but clung to Mukuro's arm, almost desperately.

"You bastard! How dare you show your face here!" Gokudera held a handful of dynamite, poised for attack.
"Nani?!" Ken bared his teeth.

"Oi Gokudera!" Yamamoto warned.

"Calm down!" Hanatsu exclaimed, slightly exasperated at his Storm Guardians actions.

"It would be wise of you to keep you guard up like that." Mukuro advised.
"I have no intention of fraternizing with the Mafia. I simply became your Guardian of the Mist Ring to seize any opportunity to take over your body, Sawada Hanatsu."

He's lying. Hanatsu thought, looking at the brunette who was clinging to Mukuro. That's not his only reason.

"So you're still..."
"Hold on Gokudera!" Hanatsu attempted to calm his Storm.
"Juudaime..." Gokudera said.

"Anways, arigatou." Hanatsu turned to Mukuro.

"I'm a tad bit weary." Mukuro's eyes began to close and his head droop.

"Take care of them for me..." The brunette tightened his hold on the body as Mukuro's image disappeared and Chrome returned unconscious.

"He turned back into a girl! What's going on?!" Ryohei exclaimed.

The Guardians were all confused. Had that been Chrome the whole time or had she been possessed by Mukuro?

"Ah! What about her organs?" Hanatsu asked hurriedly.

"Don't worry, she's fine." Reborn assured them. The spiky-haired boy nodded to them.

"She's asleep." Hanatsu was relieved that Chrome was fine.

"She collapses all the time. This is why humans suck." Ken said.

"Ken stop it. Help me carry her." The brunette reprimanded.
"Tsuna..." Chikusa said softly.

Tsuna? Is that his name? Hanatsu and Reborn thought.

'Tsuna' forced the other two to carry Chrome's body as he held her trident and directed them through the exit, only stiffly acknowledging the Vongola before leaving.

So... his name's Tsuna. I'm gonna need to investigate him. How did he hide himself so well? Reborn thought.

(1): Hanatsu is basically Tsuna in this universe. Less dame and more average. A basic description of his appearance would be about 165 cm. so taller then Tsuna but shorter then Yamamoto. Flat-not spiky- blonde hair, brown eyes. So while Tsuna resembles Nana(They aren't related in this), Hanatsu looks more like Iemitsu.
'Hanatsu' means fire, free, and release in Japanese. I also wanted to use a name that had "natsu" in it, so this fit perfectly :)
(2): Changed some of the scenes to fit the change in characters. Also, Chrome doesn't call Hanatsu 'Boss'. Why? Because I said so. Instead Sawada-sama/dono maybe.
(3): I've tried very hard to find out if Mammon/Viper is a girl or a boy in canon, but it's never been stated clearly. I think he/she might be male but I'm not entirely sure! Feel free to tell me whether you want Mammon to be stated as a "he" or a "she" and I'll change it to whatever people want most :b

a/n: I'm so happy I could cry! My very first fic xD
Tsuna's character and abilities will be explained in the next chapter so please bear with me |x
Constructive criticism is completely welcome. Heh, I'd even accept flames if someone would at least spend their time reading this!
I tried coming up with an idea that hadn't been used before. If anyone has seen a KHR fic similar to this, could you please tell me what it's called so I can read it and make sure there are differences between them? That would be a great help :] I'll probably update in the next couple of days, especially if I get good reviews~