I'm not sure specifically as I haven't read that particular fanfic. But it might be a story where Naruto is somehow cloned and has characteristics related to Thor, like maybe having Thor's strength or his hammer. It could be a really wild and creative crossover story.
There's no clear indication that 'naruto son of slenderman fanfic' is a popular fanfic. While there are many Naruto fanfics out there, this one has a very specific and rather odd concept. It may have some dedicated readers who are into this kind of mash - up, but compared to more common Naruto fanfic themes like shipping characters or exploring different ninja clans, it's probably not as well - known. However, in certain niche communities that are into dark and crossover concepts, it could have a bit of a following.
You could try looking on popular fanfic websites like FanFiction.net or Archive of Our Own (AO3). They have a large collection of fanfics, so there's a chance you'll find it there.
I haven't read this fanfic specifically. But generally, if Naruto is the son of Sephiroth in this fanfic, it would be a very interesting crossover concept. It might combine the ninja world of Naruto with the unique elements from the world where Sephiroth exists, like different powers and cultures.
He would likely have a combination of his existing ninja powers and Asgardian powers. So, he could still use his shadow clones, but also be able to summon lightning like Thor. Maybe he could even use his chakra to enhance his Asgardian abilities further.
One way this could work in the fanfiction is if there was a powerful being or artifact that manipulated genetics or destinies. This being could have decided to combine the power of Thor, an Asgardian god, with the potential of Naruto from the ninja world. So, Naruto being Thor's son would mean he has both the power of chakra and the might of Asgardian powers like lightning manipulation, which would make for a very exciting and unique story.
In this fanfic, Naruto might gain new powers or a special status. Since Thor's hammer can only be lifted by those worthy, Naruto lifting it could signify his great character. He could use the power of the hammer in battles against powerful foes in the Naruto universe, like Madara or Kaguya.
Yes, there could be such fanfictions in the vast world of fan-created works. Writers often come up with unique and creative ideas like this to explore different relationships and storylines within the fictional universes.
Yes, there might be. The idea of cross - over fanfictions is very popular. Writers often like to blend different fictional universes. In such a fanfiction, the writer would have to create a whole new backstory and set of rules to explain how Harry could be Thor's son, perhaps involving some kind of magic or alternate reality.
No. In the original Naruto series, Naruto is the son of the fourth Hokage, Minato Namikaze. Fanfics may create alternate universes, but the canonical relationship is that Naruto has no relation to the second Hokage in the official story.