Sasuke and Naruto Transmigrate to One Piece

After the final battle at the Valley of the End, Naruto and Sasuke's last strike, infused with the full force of their Six Paths powers, tore open the space at the End Valley. A space-time rift connecting to another world appeared and swallowed the exhausted pair. In the chaotic currents of space-time, the Nine-Tails within Naruto and the power of Sasuke's Rinnegan instinctively tried to protect them. However, the effort consumed much of their power, leaving them dormant or partially sealed.

Arrival: The two crashed onto an uninhabited island near Orange Town in the East Blue. They discovered that their bodies had become smaller, returning to a state around sixteen years old. The way their chakra worked resonated strangely with, and also repelled, a form of energy in this world known as Haki. A lingering “kindness” from the Sage of Six Paths resolved the language barrier.