They could be a new faction. Samurai have a strict code of honor, much like the knights in Westeros. They might be seen as a threat initially, but could also form alliances. For example, they could side with the Starks who also value honor. Their unique fighting styles would be a novelty in the battles of Westeros.
Well, if we consider samurai in the Game of Thrones fanfiction, they'd probably bring their own set of weapons and armor. Their katana swords would be different from the swords in Westeros. In terms of politics, they could try to carve out their own territory. Maybe they'd find common ground with the Ironborn in terms of their warrior culture.
In the context of war in Game of Thrones, Jack's honor would mean he would fight fairly. He wouldn't use underhanded tactics like some of the Westerosi lords. This could both earn him the respect of honorable foes and the ire of those who don't play by the same rules. His honor might also lead him to protect the innocent in the midst of the chaos of war, which is something that many characters in Game of Thrones often forget in their pursuit of power.
The Hulk might be seen as a sort of monster in the context of Game of Thrones. Just like how they have direwolves and dragons, the Hulk could be another mythical - but in this case, suddenly very real - creature. He could be shunned by some and perhaps worshipped as a god by others, depending on how different regions of Westeros react to his existence.
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.
She could fit in as a spy. Given her ability to deceive and her immortality, she could gather information for different factions. For instance, she could work for the Starks initially, but then switch sides if she saw more benefit elsewhere.
A house gardener could fit in as a keeper of secrets. The gardens often have hidden corners and old trees that could hide things. He might stumble upon a hidden cache of weapons or a secret meeting place. His presence is often overlooked as he is just a gardener, so he can observe a lot without being suspected.
Kakashi could fit in as a foreign warrior. He could bring his ninja techniques which would seem like magic to the people of Westeros. His stealth and combat skills would make him a valuable asset or a feared opponent in the battles and power plays of the Seven Kingdoms.
Smaug could potentially be a part of the magical elements in the 'Game of Thrones' fanfiction. He could be connected to the old magic that once existed in Westeros. Maybe his presence awakens other dormant magical forces. His actions could also influence the political landscape. For example, if he attacks a certain region, the lords there would have to divert their resources from the power struggles to deal with the dragon threat, which in turn could give an advantage to other houses.
Legolas could be an outcast in the Game of Thrones world at first. But as he gets to know the people and their struggles, he decides to get involved. He could start a new movement, based on elven values like harmony with nature and loyalty. His actions could inspire characters like Jon Snow to think differently about leadership and ruling, and together they could work towards a more just and sustainable Westeros.
Achilles would be an out - of - place yet fascinating addition to the Game of Thrones universe. Given his near - invincibility in battle, he could potentially change the balance of power. For example, if he fought for the Unsullied, they would become an even more terrifying military force. However, his sense of honor and heroism might clash with the more cut - throat politics of Westeros.
The Basilisk could be a fearsome weapon. A powerful lord might capture it and use it to strike fear into his enemies. Just like how dragons are used in Game of Thrones, the Basilisk could be a game - changer in battles.