Naruto x Castlevania: Nocturne
Plot:
Naruto is teleported to the Castlevania universe after his fight with Sasuke; he sees how the world is filled with bloodthirsty vampires that prey on the helpless humans. Determined to help them, Naruto becomes a vampire hunter.
Key points:
Naruto still has all his abilities (Sage Mode, Kurama, Yang Seal, etc.).
In this Castlevania: Nocturne version, he arrives before the start of the main storyline; you can make him the father of either Richter Belmont or Maria Renard.
Naruto is feared and hated by the vampire race due to his usual powers and the fact that he hunts them down.
There are some vampires that Naruto couldn't kill or those vampires that resurrect themselves (vampires that can turn into mist, smoke, etc.), So he sealed them away.
Story is a Harem (Lemons)
PM me if interested in story