One idea could be to cross it with a popular fantasy series like 'Lord of the Rings'. The dark and spooky elements of Grim Tales could blend well with Middle - earth's magical creatures and landscapes. For example, the main character from Grim Tales could find themselves in Middle - earth and have to deal with orcs and other threats while also trying to find a way back home.
A crossover with a superhero universe might be cool. Imagine the Grim Tales characters interacting with superheroes. They could be in a city where a superhero is fighting a supervillain, and the Grim Tales characters get caught in the middle. They might have their own unique powers that could either help or hinder the situation, creating an interesting dynamic.
If you cross it with 'Harry Potter', you could include Harry himself. His magical abilities and his experience with the dark arts could be an interesting addition. He could interact with the Grim Tales characters, perhaps helping them with a magical problem they have in their own world.
One idea could be a crossover with a classic fairy tale world. For example, merging the dark elements of Grim Tales with the magical world of Cinderella. The step - sisters could be even more malevolent in the Grim Tales version, and Cinderella could have some hidden powers. Another idea is to cross it with a superhero universe. Picture a superhero trying to solve the mysteries and dark secrets in the Grim Tales world. They would face challenges that are not just physical but also psychological due to the grim nature of the world.
Maybe the technology from '3 Below' gets mixed up with the magic in the Trollhunter universe. For example, Aja and Krel's advanced tech could malfunction in the Troll world and create some unexpected chaos. The Trollhunters would then have to help them fix it while also dealing with their own troll - related problems.
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.
One interesting idea could be exploring the darker sides of the characters. For example, showing how Naruto might struggle with more internal demons. Another could be re - imagining the story in a post - apocalyptic setting within the Naruto universe. Maybe Konoha has been destroyed and Naruto has to lead the survivors in a harsher world.
A more complex fanfiction could be about a prophecy that involves both Naruto's world and the Grim Tales world. Characters from both sides would have to come together, like Naruto and some of the heroes from Grim Tales, to prevent a great disaster that would affect both universes. This would involve a lot of character development and world - building as they try to understand each other's cultures and powers.
One idea could be creating an OC who is a long - lost relative of one of the main characters in Grim Tales. This OC could bring a new perspective and some hidden family secrets. For example, if the main character is a hero, the OC could be a villainous relative who challenges their beliefs and morals.
One idea could be exploring the backstories of the minor characters in more detail. For example, delving into the past of Loader Bot and how it came to be so loyal to the main characters. Another plot could involve a time - travel scenario where the characters go back to key moments in the Borderlands' history and have to make sure things happen as they should to avoid a catastrophic change in the present. Maybe also a story where the Vault Hunters from different generations team up to face a new, extremely powerful enemy that threatens the entire Borderlands universe.
One idea could be a crossover with another RPG like Final Fantasy. The characters from Tales of the Abyss could find themselves in a world filled with crystals and different magic systems. They might have to adapt to new battle mechanics and form alliances with the local characters to face a common threat.
One idea could be a story where characters from both games meet in a neutral realm due to a strange magical anomaly. They have to work together to figure out how to return to their respective worlds while facing challenges unique to this crossover situation.