You know, I've combed most of Ff. net's archives and it's amazing how there's a lack of Naruto x YuGiOh fics where actual Duel Monsters and Shadow Magic interact.
The best three efforts I've seen so far, from the bottom up is Duel Master Naruto by maverick9871 (which is more crack than anything else), Life in Naruto's World by Xero Tenshi (which is in serious need of a formatting makeover, but incredibly funny, especially in Chapter 4 where Kakashi fires a fireball and his opponent switches places with him with Mirror Gate and then Kakashi got barbequed, but I can't say anything more or there'll be spoilers, go read it and pester the author to update while you're at it) and last but not least is Naruto meets Yuugi; Duelist and Ninja Chaos by DJ Rodriguez (which is extremely creepy given how many girls are gathering over Yuugi right now and the Yuugi x Temari pairing is extremely popular.)
I'm a PuzzleShipper myself
Hence, with some extremely limited knowledge of Naruto bolstered only slightly with Narutopedia, I have written this. My hypothesis will be explained at a later date. This fic is an AU starting from the Sasuke Retrieval Arc onwards, Valley of the End scene, so read on if you like. Don't like, don't read.
I have a hypothesis concerning the Rikudo Sennin (aka Ninja Jesus) and his relation concerning Shadow Magic but the basic idea behind this fic is: The bijuu are Duel Monsters. And the Yamis are retrieving them back. Let the screaming commence.
While in this fic I will try to write the horrifying Shadow Games we know and love so much. I think there's an idea to be had with Mind Crush, Soul Rip and ninja sadism...heh, heh, heh...
*organs play in the background while lightning flashes overhead*
Well, yeah, the fic may contain Puzzle- and Tender- shipping (for those unfamiliar it's fan-code for Yami x Yuugi and Bakura X Ryou pairings respectively, unless I somehow got it wrong...) but it's not that over the top. It's more of an estalished relationship, hinted at but not exactly going to feature PWPs with Naruto characters *shudders*. Although I may indulge in Jiraiya thinking of Ryou as a girl...
Ryou: Jiraiya San, you're going to become a punching bag...
*Toad Sage panicks, runs away quickly...Bakura drags a metal bucket filled with blood over...*
Ryou: *sweatdrops* Yami, what's the bucket for?
Bakura: Preventive measures. I'm going to use the Chinese water torture on him before the pervert without equal tries anything against you, hikari.
Ryou: *more sweatdrops* then what's the blood for?
Bakura: Chinese water torture, Shadow Realm style.
Author: *smiles so sweetly that it's poisonous* Do begin.
Ryou and Bakura: The author does not own Naruto or YuGiOh, nor any of the Duel Monsters cards.
Bakura: However, the author will own whatever subsequent OCs she comes up with.
Ryou: enjoy!
Secrets Hidden in the Shadows
LLS
The secret to ninjutsu was speed. In the shinobi world, speed was everything. After all, considering that there was only so much power one could pack into the average human body, speed became the new determining factor in shinobi tactics. That, and stealth, and cunning. The strongest shinobi were thus named Kage for the shadows they embodied, able to move with the speed unknown to the ordinary, always seen yet never seen, never caught like what they were named after.
Of course, these Kage, for their skills, were still human. And humans are not a part of the realm of shadows. They do not know what hides in the darkness that forever tags their feet.
The same cannot be said for demons.
Unlike these human killers, the demons are the ones who are truly part of the shadows, truly incapable of sympathy as they kill. It is what they are, and they are powerful such that none on earth can tell them nay.
What shinobi often forget when facing such demons, is that somewhere, somehow, there will always be those who terrifies these demons. And they, whoever they are, should be feared more than the demons, the bijuu. Because demons can be understood, but the ones commanding them cannot.
He is said to be one of light and darkness, of day and night, the one with two shadows.
Those who plays games with the fates of men.
"Mou hitori no boku (the other me)...?"
The one known as Yami no Yuugi (lit. Yuugi of the Darkness), Yuugioh (lit. King of Games), one half of the Pharaoh Atemu, and a whole lot of titles and names accumulated over the centuries that mainly boiled down to Yami, resisted the urge to wince. He knew this one. It was going to be followed by the dreaded question...
"Is that supposed to happen?" the light to his darkness, Yuugi to his Oh, the other half of his soul and co-holder of the title of Pharaoh Atemu, one Yuugi Mutou, sounded vaguely sick.
Okay, maybe not the dreaded question, but it was close. For, there was only one person who would make that awful sickening squish sound...
Civility, civility...he mentally chanted. "Bakura," he stated, deceptively calm. "I remember that we are here to retrieve escaped demons. While this is also an opportunity to explore the culture of these hidden shinobi, I do believe that cutting pieces off with a meat grinder does not further our cause." Although he would privately admit that was cool, and he would keep it in mind when he started up on the punishment he would dish out upon his partner's first breakup.
Not that he would ever get a girlfriend, over his dead, cold and ground to dust bones.
The Thief King scowled further, "You're no fun." The Thief King's other half, one Bakura Ryou, looked vaguely squeamish.
"If it helps, I do believe that cutting his fingers off was justified," Yami offered consolingly.
It was after much trial and error and close shaves during the Great Chicago Event which was so epic that we cannot speak of it, when the three of them had pulled off the Jesus Christ, only without their mortal remains around (he mentally celebrated; take THAT. Ancient magic triumphs again!) that he and the Tomb Robber agreed on a fragile, holey and explosive truce.
It was six months later during their mutual problem that they realised that in the end, it was their mortal opponent who could ever understand what being a yami and a Shadow Lord meant.
Well, the Tomb Keeper, Malik, knew as well, but then somehow he whisked his good half, Marik, to Hawaii, and from the few postcards the quartet had received so far, was on permanent hiatus somewhere with Shadow Realm transport. There were several honeymoon jokes being exchanged, half of which were only remotely amusing.
It was also thus that they finally found out via Black Magician and Dark Necrofia respectively that as Shadow Lords ruled the Shadow Realm, and that by pulling off the Christ-level miracle and coming back as such, the three pairs had inadvertently bound themselves to the Shadows permanently for literally forever; the concept of an end did not make itself known to the Darkness which had been around since only God knows.
Not that he was complaining, since he and his aibou got to be together once more, but now he had to watch out for paedophiles.
And now there were escaping demons tracing back all the way to the Renaissance -and he had to wonder what was the purpose of science if people were still stupid enough to summon without watching the wording-and now nine demons were loose in a land full of shinobi and somehow the white-haired hikari-yami pair tagged along as well, the three co-rulers leaving the Shadow Realm's affairs to their competent prime ministers who had after all been doing this for three millennia, and running after the demons, or running somewhere, in the case of Malik and his hikari, Marik.
"We're approaching another country, so you might want to get the blood off before other shinobi sees that," he stated matter-of-fact, running fingers through his hair. While shadow magic was still extremely impressive, the temptation of bloodshed was present tenfold without a Sennen Item and it was so easy to fall to it and kill, say, a whole palace who tried to separate you and your light. It was thus for this sole purpose that he and Bakura had mutually agreed (gasp, horror, shock) that the lights would have two Shadow monster bodyguards each, and a truce that would hold until they reached safe surroundings.
Safe defined as outside shinobi influence, which would not be for a long time.
They had wanted four monsters, but then realised that too many monsters drew too much attention.
In a not-so-subtle jab at the land they were currently travelling, he and Bakura had chosen Ninja Master Sasuke and White Ninja respectively as primary bodyguards. Ryou had vetoed Fushi Bushi by pointing out how people would notice arrows sticking out, and Bakura had grudgingly accepted, since Ryou being kidnapped meant no hikari around to stop him in more bloodthirsty moments which could mean a repeat of Kuru Eruna, Thief King Bakura style. That and he'd mellowed out.
Somewhat...they could only hope.
In a more pragmatic approach, Bakura had willed Wall Shadow into being and set it as a scout. Acknowledging the thief's use of tactics, Yami had willed Wolf into being, Silver Fang currently working in the BEWD Corporation and thus out of commission.
Yes, the Shadow Realm had its own conglomerate, run by said Blue Eyes White Dragon. And a Starbucks. The yamis fully agreed to blame Kaiba,and ignored simple puzzles such as how the BEWD managed to do the paperwork without hands to write. The popular hypothesis was that the BEWD Burst Stream of Destruction'd all of it.
So, it was the two white-haired ones who made up the entity called the Thief King, the two punk-haired who made up the Pharaoh, a bandaged ninja with a green overall and a ninja dressed completely in white walking beside a wolf slowly trotting towards a direction resembling the approach of civilisation...
"We should have dragged that ninja along," Bakura grumbled, bored as they approached a valley with statues of ninja standing guard on either side, time and the elements having worn the stone down such that the only distinct symbol was an odd spiral shape that looked like a bird's head. "More fun to torture, if not coerce directions from. And now we're lost!"
"While I might agree with you, considering that he tried to kill us, dragging a ninja from another country across borders constitutes an international incident, Bakura. Unless the thing back in the Star Country wasn't bad enough?" Yami mildly stated.
Suffice it to say that it was lucky for them it was an unpopular and unimportant daimyo who got killed when the two yamis, for lack of better terms, sacked the palace...
As the two yamis engaged in their verbal sparring, a sudden flurry of chirps sounded...close by...
"Er...Yami," Yuugi murmured, squinting at the trees. "There aren't any birds around."
The two froze immediately as they felt the presence of one of nine they had been seeking close by. "Sasuke, Kabe," they growled in unison. "Guard formation!"