The kid could be a lost descendant of one of the old wizarding families. Maybe a long - lost relative of the Weasleys or the Blacks. Harry discovers this connection and decides to adopt the kid to preserve the family's legacy.
Perhaps the kid is from a foreign land that Naruto visited during one of his missions. The kid could be an outcast in his own place because of some unique trait. Naruto, being the kind - hearted person he is, decides to adopt him. It could be that the kid has a different kind of chakra or a strange mark on his body that makes others afraid of him, but Naruto doesn't care.
The kid could be a young demigod whose parents are unknown. Maybe he's been living on the streets, hiding from monsters, until Percy finds him.
Well, it could be that the kid has some special powers just like Harry. Harry sees himself in the kid and decides to take him under his wing. Maybe the kid is an orphan too, and Harry wants to give him a better life at Hogwarts, away from the cruel muggle world that didn't understand him when he was a kid.
In this fanfiction, maybe the kid has some special power that Naruto notices. So Naruto adopts the kid to protect him from those who might misuse his power. Along the way, Naruto helps the kid come to terms with his power and they form a really strong bond, facing all kinds of challenges from other villages and ninja clans.
Maybe Percy discovers a kid in a difficult situation, like being an orphan in a monster - infested area. He decides to take the kid under his wing to protect him from harm.
Perhaps a long - lost relative of Voldemort who has been in hiding all these years. This relative has discovered a way to gain power through Harry's kid. They might start by infiltrating Hogwarts under a false identity and slowly manipulate events to get closer to the kid. Their ultimate goal could be to sacrifice the kid in a dark ritual to bring back the dark days of Voldemort's reign.
Yes, there are likely fanfictions with such a concept. Fanfiction writers often come up with creative and out - of - the - box ideas. This particular one might explore an alternate universe where Harry Potter has a very different family origin. However, it would deviate greatly from the original canon of the Harry Potter series.
In the fanfictions, Harry being a kid might involve his reliance on adults for support, his excitement over simple magical discoveries, and his efforts to fit in at Hogwarts while still having that childlike charm and vulnerability.
Hermione is always a great character to include. As a kid, she could be shown solving even more complex problems than in the books. Her intelligence and determination can drive the plot forward in fanfiction.
Harry Potter himself is quite common. He might interact with the street kid, perhaps taking them under his wing. Hermione is also often included as she can help the street kid with their studies and understanding of the magical world. Ron could be there too, providing some comic relief and also being a friend to the street kid.