Well, in some 'Hermione and Harry Dark Fanfiction', there might be a plot where they enter a dark, alternate magical realm. In this realm, they have to rely on their friendship and skills in new ways. They could encounter dark versions of their friends and have to fight against them, which would really test their loyalty to each other.
A possible plot is that Hermione, as a succubus, discovers a connection between her new form and an ancient magic in the wizarding world. Harry and Hermione then team up to explore this connection and in the process, they uncover secrets about the origins of magic that were long forgotten. This could involve delving into ancient texts and visiting mysterious places.
One interesting plot could be them exploring the wizarding world together as a married couple, solving mysteries that were overlooked in the original books. For example, they might discover a hidden chamber in Hogwarts that has secrets related to ancient magic.
One interesting plot could be Harry and Hermione getting married and having to deal with the challenges of raising a magical family in a post - Voldemort world. They might face issues like how to educate their children about the dark past while still letting them enjoy their magical abilities.
One interesting plot could be them facing challenges from the wizarding world that doesn't fully accept their union. For example, some pure - blood families might oppose it. Another could be their adventures as a married couple, like exploring new magical places together.
Perhaps in the fanfiction, Hermione and Harry get married due to a magical bond that forms between them after a dangerous encounter with a dark wizard. In their married life, they work together to reform Hogwarts' curriculum, incorporating more Muggle - friendly and practical magic. They face opposition from some traditional pure - blood families but overcome it with their combined wisdom and courage.
Perhaps a plot where the child discovers a new form of magic that neither Harry nor Hermione were aware of. This could lead to a whole new adventure as they try to understand and control this new magic, with the help of their parents' friends and allies. It would be a story of discovery and growth, with the child facing challenges and making new friends along the way.
One possible plot could be Harry being influenced by dark magic artifacts. For example, he might find an ancient cursed object that gradually corrupts his mind and makes him turn dark. Another could be that he is betrayed by those he trusts, which pushes him over the edge into darkness.
One interesting plot could be the Dark Prince having to face his inner demons while trying to protect Hogwarts. Maybe he discovers a new, dark magic that he must either control or destroy.
Perhaps there's a prophecy that the others know about and they believe that by keeping Harry in the dark, they can change the outcome. They might think that if Harry knows the details of the prophecy, he'll act in a way that will lead to a bad end, so they're trying to manipulate events from behind the scenes without his knowledge.
In some fanfictions, their daughter might face a great threat to the wizarding world. Maybe a new dark wizard emerges, and she has to step up and use her combined heritage from Harry and Hermione, as well as her own skills and courage, to defeat the enemy. She might struggle with the pressure at first but eventually grow into a great hero.