He might ally with the Starks. The Starks' values of honor and family are similar to Aragorn's own beliefs. They would respect his skills as a warrior and leader.
In a Game of Thrones fanfic, Aragorn might also ally with the maesters. Since he has a great deal of knowledge from his own world, he could exchange information with the maesters. They could learn from his experiences, and he could gain knowledge about the politics and history of Westeros from them. This alliance could be a more behind - the - scenes kind of partnership, but it could be very influential in shaping the events in the fanfic.
Well, Aragorn is from a very different fictional universe than Game of Thrones. But if in a fanfic, he might bring his elvish connections which could be a huge advantage in the power - hungry world of Westeros. He could form alliances with the more honorable houses like the Tullys perhaps, based on his own code of ethics. And his experience in battles against great evils would give him an edge in the many wars that plague Westeros.
Aragorn's character arc could involve him initially being a reluctant participant in Westeros' affairs. But as he discovers the true nature of the threats like the dragons or the White Walkers, he transforms into a more active and determined figure. He could go from being a lone wolf to a leader who unites different factions against a common enemy. Along the way, he might also have to deal with his own inner demons and the differences in culture between his homeland and Westeros.
The Sith might form alliances with the most power - hungry characters in Game of Thrones. They could ally with Ramsay Bolton, for example. Ramsay is cruel and power - thirsty, and the Sith could use his brutality to their advantage. They might offer him dark powers in exchange for his loyalty in their quest for control over Westeros.
In fanfiction, Aragorn could potentially be a king from a far - off land who arrives in Westeros. He might bring with him a different style of leadership and a sense of honor that is somewhat different from the lords and ladies of Westeros. He could get caught up in the power struggles, especially if he realizes the threat of the Iron Throne being misused. Maybe he would try to form alliances with the more noble houses to bring stability to the land.
He could potentially form an alliance with the Starks. The Starks value honor and loyalty, and Madara, with his own sense of loyalty to his own ideals (albeit in a rather extreme way in his original story), might find common ground. He could offer his combat skills to help them in their battles against their enemies. Another possibility is an alliance with the Targaryens. The Targaryens have a connection to magic and dragons, and Madara's own powerful and somewhat magical abilities could make for an interesting partnership. He might see value in their claim to the Iron Throne and support them in exchange for certain power and privileges.
Klaus Mikaelson could form an alliance with Daenerys Targaryen. Daenerys is known for being open to different beings and powers, and Klaus' strength could be of great use to her in her quest for the Iron Throne. Also, they both have a certain air of royalty about them.
Draco might form an alliance with the Lannisters. They are both power - hungry and cunning. The Lannisters' wealth and influence would attract Draco, and they might see his wizarding abilities as an asset. He could also form an alliance with the Tyrells. The Tyrells are known for their political savvy, and Draco could use their connections to further his own goals in Westeros.
His role could be that of a savior. Just like he saves Metropolis and the world in his own story, he could save Westeros from the various threats it faces. He could be the one to stop the warring factions and bring peace, using his powers to enforce it if necessary.
If a Sith were to be a character in a Game of Thrones fanfic, it would be a wild ride. The Sith are masters of deception and power - seeking. In Westeros, they could pose as a noble from a far - off land. They would then start to make their moves, perhaps by causing unrest between the different kingdoms. They would be attracted to the power of the Iron Throne and would stop at nothing to claim it. Their presence would also attract other dark forces in the world of Game of Thrones, creating a much darker and more dangerous story.
Aragorn may develop a more complex relationship with power. As the Ringbearer, he has to constantly battle the allure of the Ring's power. This could lead to him becoming more humble as he realizes how easily power can corrupt, even someone as strong - willed as him. He might also grow in his understanding of the smaller races, like the hobbits, who he now has a new - found respect for since he is in a position similar to Frodo's.