Obviously, Harry and Hermione are the main characters. They are the focus of the love potion's effect. Whether it's Hermione being affected by the potion and having new - found feelings for Harry, or vice versa, their relationship is at the center of the story.
Draco Malfoy is frequently in these fanfictions. His family's status in the wizarding world and his complex relationship with Harry and his friends make him an interesting addition to a story about a marriage contract potion. Ginny Weasley can also be a main character. Her relationship with Harry in the original series can be further explored or twisted in fanfiction involving the potion.
Draco Malfoy might also be a key character. He could be the one who uses a love potion on someone out of envy or to gain some sort of advantage, or he could be the victim of a love potion, which would completely change his usually haughty and cold - hearted demeanor.
Often, Harry Potter himself could be one of the main characters in such fanfictions. Maybe he has an accidental love encounter with a new character introduced in the fanfiction, someone who might be from a different house or have a unique magical ability.
Draco Malfoy is also a common character in such fanfiction. He could be the one rejecting love or having his love rejected. Maybe he falls for a muggle - born witch but his pure - blood family values make him reject his own feelings. Or, a Gryffindor girl could reject Draco's advances because of his past bullying, which would be an interesting exploration of how Draco might change or react to such rejection.
Obviously, Hermione herself is the central character as it's about her brain drain. Harry and Ron are usually also important characters as they are Hermione's closest friends. They are often the ones who first notice the changes in Hermione and try to figure out what's wrong.
Harry Potter himself can be a central character in such fanfics. He might be the target of a love potion, either by accident or as part of a villain's plot. Since he's the main hero, he would then have to struggle with the false feelings while also trying to protect his friends and Hogwarts from any danger associated with the love potion situation.
Naruto himself is obviously a very common character as the title implies. Sakura is also often involved as she has a complex relationship with Naruto in the original series. Sasuke might also show up as he is an important part of Naruto's life.
Obviously, Hermione and Ron Weasley are the main characters. Since it's about the marriage law related to the Weasleys. Harry Potter might also be involved, as he is their best friend and could be dragged into the situations that arise from the law. The other Weasley family members, like Molly and Arthur, could play important roles too. Molly might be concerned about how the law affects her family, and Arthur could be involved in any political or magical - government - related aspects of the law.
Ron could also be there. He might be in charge of something like the Gryffindor Quidditch team or be a part - time teacher teaching the younger students about the magical history of the Weasley family's inventions. His humor and loyalty would be a great addition to the story.
Obviously, Harry Potter himself is often a central character. His friends like Hermione Granger and Ron Weasley also frequently appear. In some fanfictions, they might play different roles compared to the original books. For example, Hermione could be the one who stumbles upon a dark secret first and has to convince Harry and Ron to take action.