In this fanfiction, Harry could be raising his little sister after a tragic event that left her orphaned. He would take on the role of a parent figure. He'd be responsible for her daily needs like getting her to school (a wizarding school of course), helping with her homework, and dealing with her teenage angst when she grows up. He would also have to pass on the values he learned from his own experiences, such as the importance of friendship and standing up against evil. Maybe he'd even train her to be part of a new generation of wizards to fight against any emerging threats in the wizarding world.
Well, perhaps in the fanfiction, Harry's little sister has some unique magical ability that attracts unwanted attention. Harry then has to raise her while constantly fending off those who would use her for their own purposes. He would have to balance being a brother and a protector, making sure she grows up happy and safe in a rather dangerous magical environment. He might also introduce her to his friends at Hogwarts for support and guidance as she gets older.
In the fanfiction, Harry might raise his cousin in an attempt to break the cycle of animosity that has always been between them. He could show his cousin a different side of life, full of magic and wonder. Harry could also protect his cousin from the dark forces that are always lurking in the wizarding world, and in the process, his cousin could become a valuable ally to Harry.
In a 'Harry Potter and His Little Sister' fanfiction, the sister could be a new student at Hogwarts when Harry is in his later years. She struggles to fit in because of being Harry Potter's sister. Harry has to help her deal with the pressure, make friends, and also face the threat of a new dark wizard who has a vendetta against the Potter family.
In this fanfiction, Naruto's ninja skills could play a role in his sister's protection. He might teach her basic self - defense moves early on. Also, his friends in the village could become like aunts and uncles to his sister, providing different kinds of support and influence. For instance, Sakura could teach her some medical knowledge.
It could also be that Harry and Lemon inherit an old family heirloom that has some sort of magical power. But they don't know how to control it at first. So they embark on a journey to find out more about it, meeting various interesting characters along the way, and in the end, they learn to master the power and use it for good.
He might start with the basics at home. Since he has his own experiences at Hogwarts, he can teach her things like the levitation charm. He could use simple objects around the house to demonstrate magic.
One possible plot could be that the female Harry Potter, using her magic skills, finds Naruto in a different dimension or perhaps when she accidentally travels to the Naruto universe. She decides to take him under her wing. She could teach him some basic magic concepts, which Naruto might adapt in his own unique way for his ninja skills. For example, he could use the idea of transfiguration to change the appearance of his shadow clones in a more complex way.
One possibility could be that Harry, with his knowledge of magic and experience in fighting dark forces, takes Tsuna under his wing in the magical world. He could teach Tsuna about different spells and how to handle magical creatures, which would be a new and exciting experience for Tsuna who is used to his own world in 'Katekyo Hitman Reborn!'.
Well, in this fanfiction, Kakashi might introduce Harry to the concept of chakra. Since Harry has magic, Kakashi could find a way to combine the two powers. Maybe Harry would learn to use chakra to enhance his spell - casting speed or accuracy. And Kakashi would also help Harry deal with his emotional traumas, like the death of his parents, in a more ninja - like, stoic way.
Well, in this fanfiction, Deadpool might raise Harry Potter in a world where the two universes collide. Deadpool could introduce Harry to the concept of fourth - wall breaking, which would be really strange for Harry. He could also take Harry on adventures that involve both the wizarding world and Deadpool's own crazy world filled with mercenaries and mutants, leading to some really unique and comical situations.
Maybe Harry starts raising chickens because he wants to have a normal, non - magical hobby. He finds some regular Muggle - like chickens in a nearby village. As he raises them, he realizes that they have an uncanny ability to sense dark magic. So, they become like an early warning system for any approaching danger at Hogwarts. This could lead to all sorts of adventures where Harry has to protect his chickens from dark wizards who want to use their power for evil.