So.. This is the first fanfic I've written in a while (so be nice).
It's based off a role-play with a friend of mine (YOU KNOW WHO YOU ARE BBY).

The idea is of a parallel universe where the Millefiore was destroyed from the inside before they even got to the choice battle. I guess its an AU of sorts and I will try to stick to the original KHR plot as often as possible so please bare with me if I change one or two things. This is gonna be quite a long fanfic and I'm rating it T for now but I might change that later
All rights to the anime, manga and characters belong to Akira Amano and other respected creators.
I hope you enjoy

Mukuro looked around at the cold; white room and sighed. His memory was fuzzy thanks to the drugs and heavy kick he'd taken to the head. As the events of the previous days began to resurface he cursed his own idiotic confidence. Of course the white-haired don would have discovered his real identity. Now that he thought about it; Byakuran had probably known for a while now - he'd simply been playing the game as well. He thought back to the very moment things had gone wrong...

"I have prepared the reports for you, Byakuran-sama"

"Ah Leo! you never cease to amaze me~ how do you get all of these reports filed so quickly and so expertly?" The angelic smile plastered on the mafioso's face was another special ability he seemed to possess - how could he smile so perfectly and yet so dishonestly?

Then of course there were those damn flowers; he'd been a little bit cocky buying them for the man, he had to admit. Those traitorous plants that had so cruelly given him away; forced him to reveal his true self.
"Kufufufu, so you're finally putting an end to this game?~"

The battle hadn't taken long; he was no match of course. Byakuran soon had him on the floor clutching his bleeding eye and straining just to keep himself from collapsing on the spot and loosing consciousness. His side ached and his trident lay broken in the corner; the greatest illusionist in the world defeated so easily. At first he just couldn't accept that fact, but as it began to sink in he lashed out one final time. That earned him another kick to the ribs. He keeled over again and clutched at what he was sure was already a very impressive bruise.
Byakuran took hold of his hair and pulled him up to half his own height, grinning madly in a way the bluenette was sure that psychotic prince of the Varia would have been proud of.
Then the white-haired lunatic had leaned over him and whispered softly into his ear "I think I may have some use for you yet.. "

He woke up a few hours later in the mafia boss' room; lying on the bed completely naked, handcuffed and cold - wrapping the blanket around him he got up and wondered around the room; looking out of the windows and pushing on the door - locked of course. The room looked out upon the city - a busy and bustling city where the people may as well have been ants from where he stood; Mukuro could imagine Byakuran standing there in just a year's time looking out upon the charred remains and smoldering ash of what was once Namimori. He could see the man's smug face twist into a grin as he took in his surroundings and laughed at all those who died in the battle to come. Of course its not like he really cared either - it was his own goal to possess Tsunayoshi and destroy the world himself one day. There were however a few people he would miss when that time came; Ken, Chikusa, Chrome and of course his faithful student Fran. However he just couldn't let this.. marshmallow-obsessed moron take over the world before he had a chance to squeeze the life from it first! Absolutely not - and this place would be the first to go when he achieved that target.
As he circled the room for the third time the memories of the previous couple of days began to flood back - he clutched at his stomach and suddenly felt like vomiting right in the middle of the pristine, white floor. That surely would spite the madman.

He'd let that man fuck him... and what really made Mukuro's stomach turn was that he hadn't put up much of a fight. He could blame the drugs; the dizziness; maybe the mafioso had even gotten him drunk to a point (something you should never do to an illusionist so he highly doubted that) - but he knew deep down that he hadn't put up his best effort of resistance.
And he knew why. He was defeated; useless and pathetic. Why should he put up a fight when he wouldn't have won anyway?
Mukuro was never the most positive of people. It was one of the reasons he hated the Vongola brat so much - all that stupid positivity would get him no where. He had to be able to see what was real and what wasn't - and any chances of him escaping Byakuran back then were completely unrealistic.
So he submitted. It still made him feel utterly disgusting though, and next time he'd definitely make sure to let Byakuran know that.

Byakuran sat at his desk and smirked - the drugs he'd been having put into the illusionist's food would be starting to wear off finally. He'd be able to mentally scar the man now too. He could even have intelligent conversations with him! This is what he'd been waiting for - to have the Vongola's infamous mist trapped and tortured - but in full knowledge of what was happening. He could watch as his cute little captive's mind finally broke and he gave in to the boss of the Millefiore. That would surely teach the Vongola a lesson they'd never soon forget - that they should never ever mess with someone as powerful as him.
He scooped another helping of his favourite vanilla and marshmallow sundae into his mouth and thought about the illusionist in his room right now. He was probably trying to think of some escape plan that would have no chance of working. Byakuran began to wonder if he had ever come across anti-illusion handcuffs before. Coupled with the shielding he'd had put up around his room and the decoy cell he'd had made he highly doubted anyone would attempt a rescue mission any time soon; or that the illusionist would find a way to escape by himself for that matter - he could not afford to underestimate his enemies at this current time.
After about an hour of only thinking of the man locked in his room he finally got up to return there, smirking. Oh, he couldn't wait to explain Mukuro's current situation to him and watch the expression of utter horror overtake the now-powerless magician's face. He licked his lips and opened the door.

Sorry if this seemed a bit short and badly written
(and for all the spelling mistakes originally made which I hope have now all been corrected)

I'm working up to longer chapters, I swear! But yeah.. I hope none of you hate Byakuran too much right now because I plan on making his character so much worse and then letting him redeem himself later in the plot. Another warning that there will be some dark themes later in the plot - and Byakuran's sadistic personality is kinda leading up to that (I hope).