Fanfictions could explore what would happen if the dragons from How to Train Your Dragon were brought into the political intrigues of Game of Thrones. Maybe they become powerful weapons or sources of hope in the battle for the Iron Throne.
There could be fanfictions where the magical elements of Game of Thrones merge with the dragon-training techniques from How to Train Your Dragon. For example, someone using magic to better understand and train dragons.
You might find crossovers where characters from both universes interact in unexpected ways. Maybe a dragon rider shows up in Westeros or a Game of Thrones character discovers a dragon egg in the land of Berk.
You could have a story where characters from How to Train Your Dragon find themselves in the world of Game of Thrones and have to navigate its politics and dangers.
One idea could be a story where Kratos finds himself in the world of Westeros. Maybe he gets involved in the power struggles between the houses. He could use his combat skills to fight against the White Walkers, bringing a whole new level of action to the fight against the undead.
In such a fanfiction, perhaps the concept of the Sharingan in Naruto could be related to some sort of immortality in the Game of Thrones universe. Characters with the Sharingan could see the future and avoid death, like they do in Naruto. They could then use this ability to manipulate the events in the Seven Kingdoms. They might side with different houses based on their own goals, all while trying to keep their immortality - related secret safe from those who would do them harm.
One idea could be to have Percy Jackson transported to the world of Game of Thrones. Maybe he arrives in Westeros and is mistaken for a powerful sorcerer because of his demigod powers. He could get involved in the power struggles between the different houses, using his skills in combat and his ability to control water to his advantage.
To write such a fanfiction, you could begin by deciding on a central conflict that ties in with the themes of both. Maybe a powerful enemy threatens both Berk and Westeros, forcing them to work together. Also, pay attention to maintaining the tone and style of both franchises to make the crossover feel seamless.
One interesting fanfiction could be one where the political intrigue of 'Game of Thrones' is set in the lost city of Atlantis. Maybe the houses of Westeros are reimagined as different factions in Atlantis, vying for control over the advanced technology or magical artifacts that Atlantis is rumored to possess.
Obviously, the Dragon King himself is a main character. He is usually depicted as a powerful and complex figure, with his own goals and desires for the kingdoms. Daenerys Targaryen is also often present, either as an ally or a rival to the Dragon King, given her own connection to dragons in the original series.
One idea could be to create a story where the ninjas from Naruto are inserted into the political intrigue of Westeros. For example, Naruto, with his strong sense of justice, could find himself in the middle of the power struggle for the Iron Throne. He might try to use his ninja skills to bring peace to the war - torn land, much like he did in the Hidden Leaf Village.
The fanfiction about Howland Reed in Game of Thrones can range from epic battles he participates in to emotional journeys of self-discovery. Some might even imagine alternate timelines where his decisions shape the fate of the entire realm differently.
There are some really cool ones out there. For example, some fanfictions might explore how a character from House Potter would fare in the complex and dangerous world of Westeros from Game of Thrones. They could bring magic from the Potterverse into the political intrigue of GoT.