Naruhodo: The Rasengan Admiral, Stranded in One Piece (R18)

After he died, Naruto believed he was going to the afterlife. But opening his eyes, he finds himself stranded on an island with no powers except a window and a strange fruit in his hand.

He's also younger. A lot younger than when he died.

All the women of his past life are on that island as well? And they're weak?

........................

"Is this the afterlife?" Looking at something called levels on the interactive, translucent surface, Naruto wondered. The island was different from the motley, spiritual expanse where he met his parents.

"But what are all those beasts on the land and the sea?"

When he frowned, weirded out, he saw a beautiful auntie passed out on a beach. The next day he saw another, more familiar figure there.

........................

Happy in love, Naruto was still bewildered.

Unbeknownst to him, something which he would only find out later, they were transported to a world of pirates, bounty hunters, and sea guardians.

Weeks later. Looking at the sullen, dark-haired, large chested woman with a mole on her face, and who wore a mantle with a seagull adorned on it, he chewed over, "Marine? Vice admiral? Pirates?... I'm not sure what this big chested woman's talking about, but she's making my choice easy with this cleavage."