An interesting idea is that Jim gets hurt because of a mistake he makes. He could be overconfident and break an important rule in Trollhunting, which results in him getting injured. His friends then have to decide whether to help him despite his mistake, and Jim has to learn from his error while he heals.
Jim could be hurt by a new type of dark magic that the trolls are using. This would force his friends to research and learn about this magic to find a cure. It could also introduce new characters who are experts in this kind of magic.
One possible fanfiction could be where Jim gets seriously hurt during a battle with a powerful troll. His friends then have to find a way to heal him, perhaps by seeking out a rare magical herb that is said to have great restorative powers. This could lead to a journey filled with various challenges and character development for his friends as they race against time to save Jim.
Another plot could revolve around their families' reactions. Jim's mom might be overjoyed but also worried, while Claire's family could have some mixed feelings. There could be cultural differences in how they approach the pregnancy, especially considering the troll - human aspect. And they have to navigate through all these family dynamics while also preparing for the new life coming into their world.
You could also create an OC human who discovers a hidden talent for communicating with trolls through music. In the fanfiction, this character could use their musical ability to bridge the gap between the two worlds, maybe even creating a new form of harmony between trolls and humans that was previously unthinkable.
One idea could be a crossover where Naruto characters end up in the Trollhunters' world. Maybe Naruto and his friends could learn about the trolls' unique magic and fighting styles. For example, Naruto might be intrigued by the way trolls use their strength and size in combat and try to incorporate some of those elements into his own jutsu.
How about a crossover with the Percy Jackson series? The Trollhunter could meet Percy and his friends at Camp Half - Blood. Since both deal with mythical creatures, they could exchange knowledge about different mythologies and fight side by side against monsters that are drawn to the power of trolls and the demigods.
In a Jim x Morgana fanfiction, it could start with Morgana being trapped in a magical prison created by the Trollhunters long ago. Jim, out of his sense of justice and curiosity, decides to visit her. As he gets closer, he realizes that Morgana has a complex past and motives that are not entirely evil. Their interactions could then develop into a strange friendship that the other Trollhunters might not understand.
For 3 below trollhunters fanfiction, you could write a story where the characters get stranded on an unknown planet during one of their space travels. They have to use their skills and knowledge from both their home world and what they've learned on Earth to survive. Another plot could be that a new alien race arrives on Earth, and the 3 below characters have to decide whether to trust them or not, while also dealing with the trollhunters' reactions. And, a story about the characters trying to find a way to reverse the damage they've accidentally caused to the environment on Earth would also be great.
Well, 'trollhunters jim and claire fanfiction' has a wide variety. 'The Bond of Two Souls' is a really good one. In this story, Jim and Claire discover a new magical bond between them that gives them unique powers. 'A New Day for Jim and Claire' is also interesting. It shows how they handle normal life in Arcadia while still being trollhunters. And 'Claire's Choice' is about Claire making a difficult decision that impacts her relationship with Jim in a profound way.
Another idea is a crossover with 'Avatar: The Last Airbender'. The Trollhunters could meet Aang and his friends. They could combine their powers to defeat a common enemy that has the ability to disrupt both the balance of the four elements and the Troll world's magic. For example, they could fight a dark spirit that is draining the magic from the Troll world and using it to spread chaos in the Avatar world.
One idea could be that the characters from Trollhunters and 3Below have to team up to fight a common enemy that is threatening both their worlds. Maybe an ancient evil that has the power to destroy Arcadia and Akaridion - 5. Another could be a story where the technology of 3Below is combined with the magic of Trollhunters to solve a mystery that has been plaguing both species for centuries. For example, a mystery about a long - lost artifact that has the power to reshape their universes.