After thinking things through, I realised that this idea might be interesting for someone to adopt, along with using a different twist, but if anyone wants to put their own spin on it they are more than welcome to.
I figure that by using basically the same story as my "A New Devil's Marvellous Adventure" one-shot, it'll everyone see that it doesn't have to be just the Marvel world that Naruto ends up in.
A New Devil Sailing
Chapter 1
Pilot
Unknown Location
Standing in front of a swirling vortex was a tall silver-haired man, wearing a red trench coat with a sword on his back, holding another sword in his hands, with a two-sided amulet wrapped around the handle, guard and blade, a female voice called out to him, "Are you sure you want to do this Dante, I mean, it's your father's sword and your mother's amulet?"
Sighing, the man looks towards the speaker, "It's the only way Lady, doing this not only stops the vortex, but stops demons and other beings from trying to get Forced Edge, along with the amulets, it's the only way, I'm sure my old man along with my mother would've done the same thing if something like this happened to them, hell, he sealed his powers into his sword and closed the gates to the demon world himself with my mother's help, besides, you never know if my brother is still out their, so this is killing at least three birds with one stone."
The woman with him still has doubts, "But what if someone finds the sword on the other side, it could be anyone."
With a wave of his hand, he replies, "Relax, this sword's power will keep it all sealed, kinda like a black hole, sucking and holding everything together until it's settled, then sparda will be sealed as well, no worries."
Before she could say anything, Dante threw the sword into the vortex like a javelin, causing the portal to close in on itself, vanishing from the face of the earth, all the while Dante thinks to himself, "Mother, Father, while I may no longer have your sword and amulet, I'll always have you in my heart, because even a handsome devil like myself may cry."
His friend, Lady moves towards his side, placing a comforting hand on his shoulder since he gave up something precious to him, hoping he did the right thing.
Naruto's World
At another point in time, in another dimension, years after the sealing, was the Fourth Shinobi War, with 2 teens fighting a single woman with horns.
The two managed to release everyone from the Shinju tree, allowing them to evacuate from their fight, though the woman was angry at the lost of chakra, causing her to fight even harder, luckily, with the help of the boys teammates, they managed to seal her away in another dimension that the woman created, along with her creation that was filled with her dark ambition.
But there was one problem, the moment the two were sealed, the rabbit goddess flung the blond boy through a portal as a last act of defiance, with his pink haired friend yelling out his name, "NARUTOOOOO!"
Inside the portal
While "travelling," the blond teen known as Naruto was floating through a strange and unknown place, with bright flashing colours, suddenly he catches a glint of something spinning towards him, "What the hell is that!?"
The exhaustion of his fight with not only Kaguya, but Madara, Obito and the war really pushed his stamina to the limits, now he was tired, bruised and aching, until the object got close enough for him to see a strange sword approaching him, that is until he finds the sword embedded in his chest, he was too exhausted to move let alone dodge out the way.
His eyes widened, due to the sword hitting him, it made him slow down enough to exit the portal, he could feel his energy slowly leaving him.
Rogue Town
It was night outside, the only ones out were a few couples and nighttime animals here and there, though the couples were on their way back to their places, never noticing something landing in an ally. (A.N. Whoever said Naruto's "landing" had to be loud and explosive.)
Laying on the ground was Naruto Uzumaki, the sword still stabbed in his chest, his eyes half-lidded, as though his mind wasn't there.
Naruto's Mindscape
At this moment, Naruto was laying in his mind, due to Kaguya's interference, Kurama was removed from Naruto, but thanks to Haguromo's help, Naruto still lived, but now the leftover tailed beasts chakra from the others were slowly ebbing away trying to heal him, but because the sword wasn't removed, the chakra couldn't do anything.
Though standing over Naruto was a regal looking man, wearing a purple Victorian style outfit, looking at the teen in front of him, "While I commend Dante's sacrifice of my sword and his mother's amulet, he may have just past on my legacy to someone more ideal, if what his memories tell me, along with the leftover energy of those tailed beasts he'll possibly become a full devil, like myself, if he wants to accept my power."
The regal man took a knee, getting closer to Naruto, though at this moment Naruto was too weak to do anything, except look towards the man, hearing everything the man said, "Please listen to what I have to say young Naruto, while I may not be human I have come to accept them as apart of the world, I even fell in love with one, showing that even a devil has a heart, I protected the humans by going against my own kind, now I stand before you, asking you to take my power for your own, become a devil yourself in order to protect others, if you do this you'll live, because you see, my sword is still in your heart, the only way for you to live is by becoming my successor, please, I can not let a human die by my sword."
Hearing the devil say such heartwarming things, Naruto couldn't believe someone was putting their trust in him and a devil at that, granted he would die because of the sword in his chest, but the devil gave him a choice, to live as a devil or die as a man, thinking things through as quickly as his weakened body can, Naruto slowly nods his head.
The devil nods back in understanding, "Remember this Naruto, that even a "Devil May Cry" when they lose a loved one, so take care my son."
Hearing the devil call him 'son,' made Naruto happy, granted he had a father, but now he has two fathers, "Before we start Naruto, know that this will be painful, once my power enters you, along with the tailed beasts chakra, both just may overload your chakra network, destroying them completely, but, because you'll be a devil, you'll still live and heal from it, but you'll not be able to use your chakra."
So he had one more choice, lose his chakra and have it replaced with his devil powers, or keep his chakra and lose his life as well, "Whatever, I agreed to it at the start, so I may as well continue with this, since I am Naruto Uzumaki and I don't back down."
With another slow nod, Sparda knows Naruto accepts the deal, standing back up, Sparda moves back slightly, holding one hand out towards Naruto and the other towards the leftover chakra, then starting the process, the tailed beast chakra passes through Sparda and enters Naruto, causing Naruto to start shaking in pain, as though he was being electrocuted, but the power rushing through him now manages to get Naruto to find his voice.
"AAAAAAAAAAAAAAAAAAARRRRRRRRRRRRRRRRRRGGGGGGGGGGGGGHHHHHHHHHHHHHHHH!"
The power started changing his appearance, turning his skin to lighter tan, his hair went from sun-kissed blond to silver white, his body began to become stronger and heal rapidly, giving his body a lean muscular look, he became taller, closer to Sparda's height, his whisker marks were now fainter, almost like you couldn't see them unless you were looking for them, his eyes changed to a more lighter colour, instead of a deep sea blue colour, they were now a bright cloudless sky blue colour, his canines became slightly more fang-like.
His face became more angular, losing his baby-fat, making him look more handsome.
As the process was nearing completion, Naruto and everything became surrounded by a bright light of white, blinding him and knocking him out, during which Sparda finished things off by giving Naruto knowledge of his sword techniques, though he'll need a catalysis to unlock Forced Edge's awakened form, but Naruto wasn't ready for that, yet.
He also gave Naruto the language part of being a devil, meaning that he'll naturally know mans language. (A.N. Got the idea from Highschool DXD.)
Dark Ally
Suddenly, Naruto opens his eyes, his body already changed, due to the power flux, his jacket and shirt was burned off, showing his lean body, sitting up, Naruto looks around, wondering where he was, feeling slightly confused at everything around him, slowly standing up to get more bearings, he rubs the back of his head, "Okay, this place is definitely not the Elemental Nations." Noticing his voice was deeper.
Suddenly, in the corner of his eye, or just under it, he noticed something, "Huh!?" There sticking out of his chest was the sword known as Forced Edge, or the sword so powerful that it was named after it's original owner, Sparda, "Well, this is annoying."
In his confused state, his mind hadn't caught up to what was happening yet, but it was slowly getting there, "WHAT THE HELL, WHY DID I SAY THAT WITH A SWORD STICKING OUT OF MY CHest!?" As he quietens down, he realises that it's not quite as painful as it should've been, placing both his hands on ether side of the blade, he completely removes the sword from his chest, a spurt of blood exiting him, though when the blood lands it disappears from sight.
Looking at where the "opening" should be, all Naruto saw was a line of blood but nothing else, "Okay, that is both awesome and weird at the same time, I guess the old devil was right about me, though I still feel weak, but that's might be because of the chakra network."
Grabbing Sparda's handle, removes the amulet wrapped around the sword and knows the jewellery was important to Sparda, so Naruto hangs the amulet around his neck, Naruto then subconsciously places the sword on his back, where it naturally hangs somehow.
Looking behind himself, noticing the swords was strangely hang, Naruto shrugs his shoulders, "Well at least I won't have to worry about a sword carrier or a sheath, but now that I'm here, what should I do now."
Trying to think of something, Naruto was interrupted by a voice behind him, "Hey kid, are you alright, did a couple of pirates beat ya up?"
Turning around, Naruto noticed an old wearing a white, red-hemmed shirt, and the same earrings, necklace, hat, and glasses, having just spotted Naruto after he hung his sword, "Come on kid, I'll give ya something to drink, then tomorrow we can get ya some new clothes."
Naruto, being who he is, gives a big toothy grin, showing that Naruto was still Naruto, if only slightly, "The name's Naruto Uzumaki old man, thanks for the help, I'll be sure to pay ya back at ya bar!" The old man's eyes widened, an afterimage of another more infamous man overlaid onto Naruto, making him nervous, "C-Could it be possible that after these years, a new legend is gonna be born!?"
Naruto became curious at the man's silence and wide eyes, as though he'd seen a ghost, "Hey, old man, you alright, ya not having a heart attack or something are ya!?" Knocking the man from his thoughts, "I'M NOT THAT OLD YET YOU BRAT, now come on, my bars this way."
The End.
There you have it, Naruto/Sparda in the One Piece world, no Rebellion sword or Yamato, just Forced Edge and the amulet.
Though because of it being the One Piece world, there'd be plenty of enemies for Naruto to face, via pirates, maybe he'll get his own ship and call it "Devil May Cry" ship, with the logo painted on his sail in purple and red luminous paint, got the luminous paint idea from "Only Fools and Horses The Yellow Peril" episode.
Though if anyone wants Naruto to be apart of the straw-hat crew, but I can see Luffy watching Naruto facing against a group of pirates and saying how cool that was, since Naruto would re-enact Dante's intro from Devil May Cry 3, along with wanting Naruto to join his crew, it's up to whoever adopts.
As for the pairing(s) I can see Nami taking an interest in Naruto because of his amulet, along with Robin for his knowledge of his own world, he could also take Luffy's place for Amazon Lily, it would surprise them when Naruto's sword returns to him by merely holding his hand out, along with the arrows not killing him, but instead annoy him, though he wouldn't want to keep being shot by arrows, since they would be a pain to remove. lol
I Do Not Own Naruto Or One Piece. (Or Devil May Cry.)