Fan Fic: The Biju Biju Fruit
"12 years ago the great Gold Roger, King of the Pirates, died, executed by the Marines. Right before he died, he told those were listening that they would have to search the world for his treasure, One Piece, and started the Golden Age of Pirates.
"4 years ago in the village of Fuchsia, the strongest of the Biju, the Kyubi: The 9 tailed fox attacked. The one who saved them was a mysterious nameless hero, known only as the 4th Hokage; however the only way to stop it was sealing it into a baby. He asked the family of a newborn baby if he could do this, which they reluctantly agreed to. He sealed the demon into the baby and his final wish was for this small village to see him as a hero. Sadly only the baby's family and a few villagers saw him as such. The others saw him as the demon. The mayor made it illegal to talk about the demon within the child will never know about it then something happened one day."- The opening lines (edited).
The Biju Biju Fruit is written by Emma Iveli
and is (probably) the longest running One Piece/ Naruto crossover on Fanfiction.net. The story is a retelling of One Piece with Naruto characters inserted into many roles (occasionally replacing One Piece characters).
Monkey D. Luffy and Fox D. Naruto are brothers who live in Fuchsia Village. One day Luffy ate the Gum Gum Fruit while Naruto ate The Biju Biju Fruit Model: Kyubi. However should the eater of a Biju Bju Fruit have the demon sealed within them it will have different effects than those that hadn't, it was because of this Naruto learned of the fearsome (and perverted) demon within him. 10 years later Luffy and Naruto begin their quests to become Pirate King (Luffy) and a Kage (Naruto). A Kage is the greatest of all clone users a type of fighting style that allows one to multiply themselves in many ways. Along their way they gain a crew consisting of: former bounty hunters Roronoa Zoro and Uchiha Sasuke, thieves Nami and Sakura, sons of a pirate they once knew Usopp, Kiba, and Kiba's dog Akamaru, chef Sanji, assistant chef Ino, Luffy and Naruto's childhood friend Hinata, Chopper, a talking reindeer human, Gaara, a fellow demon host who didn't know what love was until Naruto got though to him, Nico Robin, a mysterious woman, and Isaribi, a girl who was experimented on to turn into a strange half human, half fish hybrid.
The story is currently in the Water 7 saga.http://www.fanfiction.net/s/3122941/1/The_Biju_Biju_Fruit