One possible storyline could be that the child is a result of a relationship Harry had during his later years at Hogwarts that was kept secret. Maybe it was with a foreign witch he met during one of his adventures outside of Hogwarts. The child could inherit Harry's magical abilities and also some of his personality traits like his courage and sense of justice. Then the story could focus on how the child discovers his or her true identity and the legacy of being Harry Potter's offspring.
There would be a great deal of excitement among the younger generation. They would see Harry's child as a new kind of celebrity. The media in the wizarding world, like the Daily Prophet, would go crazy, trying to get every detail about the child. The Hogwarts professors would likely be very interested in having the child at the school, hoping to see if the child has the same potential as Harry. But there would also be some old - fashioned families who might be worried about the child's blood status, even though Harry is a pure - blood hero, just because of the secrecy surrounding the child's birth.
A plot might be about Harry's child struggling with the pressure of living up to their father's legacy. At Hogwarts, they constantly feel compared to Harry. But then, they find their own niche in the wizarding world by being really good at potion - making. They enter a big potion - making competition and end up using their skills to save the day when a dark potion goes wrong and starts affecting students. They prove that they can be great in their own way, not just because they are Harry Potter's child.
It could be a new dark wizard who is jealous of Harry Potter's fame and success. This dark wizard targets Harry's child, thinking that by causing trouble for the child, they can somehow diminish Harry's reputation in the wizarding world. He might try to frame the child for various dark magic incidents around Hogwarts.
There are indeed 'Harry Potter is secretly married' fanfictions. Fanfiction writers often take creative liberties with the characters. They might imagine a scenario where Harry has to keep his marriage a secret due to various reasons such as threats from dark forces or to protect his family. This kind of fanfiction can range from light - hearted and romantic to dark and full of intrigue, depending on the writer's vision.
One challenge could be the public perception. In the wizarding world, Snape is often seen as a villain or at least a very unlikable character. So for Harry to be secretly with him, Harry would have to deal with the potential backlash from his friends like Ron and Hermione, who might not understand his new relationship with Snape.
Perhaps the plot could be that the child of Harry Potter gets sent back in time accidentally. There, they meet a young Harry and his friends. The child has to be very careful not to disrupt the past too much while also trying to find a way back to their own time. This would be filled with lots of tricky situations, like when they almost reveal future events or when they have to avoid being seen by their own young parents.
In a Bellatrix and child Harry Potter fanfic, the author might explore the idea of Bellatrix having a change of heart towards Harry. It could start with her seeing some of James Potter in the young Harry. This could lead to a series of events where she tries to protect Harry from other Death Eaters, which would be a huge deviation from her character in the original series. However, it would make for a very interesting and unique fanfic.
It could be a fanfiction that focuses on the idea of a character in the Harry Potter universe remaining a child forever. Maybe it explores how that character's eternal childhood affects their relationships, their magical abilities, or the overall plot of the story.
Definitely not. J.K. Rowling created a magical world full of wonder and positive themes. The concept of a child bride has no place in this world. It would be a perversion of the original story and its intended audience, which is mainly children and young adults who are supposed to be inspired by the good values in the books.