Well, it depends on the skills the modern person has. If they are into martial arts in the modern world, they could potentially use some of those fighting skills in 'Game of Thrones'. But they would still face challenges. The political intrigue is so complex there. A modern person might accidentally break some unspoken social rules and get into trouble. For instance, not knowing how to properly address a noble could lead to serious consequences.
Well, in a Game of Thrones fanfiction, a modern soldier could potentially change the power dynamics. Imagine a soldier with his combat boots and Kevlar vest suddenly appearing. He could use his military discipline to form alliances. He'd probably be shocked at first by the magic and dragons, but his ability to quickly assess situations and act could make him a valuable asset or a feared enemy. Maybe he'd try to introduce modern concepts like democracy or human rights, which would be very different from the feudal system in Westeros.
Hashirama would likely be a very powerful force in the Game of Thrones world. His skills as a shinobi and his ability to control nature could give him an edge. He might try to use his powers to bring peace, similar to his goal in his own world, but would soon realize the complex and cut - throat politics of Westeros.
In a fanfiction, the Union Army could change the power dynamics completely. Their presence could force the different houses to either ally with them or against them. If they were to support a claim to the Iron Throne, that person's chances would increase significantly. But they would also face opposition from those who see them as outsiders and a threat to the traditional ways of Westeros.
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.
The common people from the Roman Empire would face a lot of difficulties. The harsh winters, the constant threat of war, and the feudal system in Westeros are very different from what they are used to. But some might be able to use their skills in farming, building, or trading to carve out a living in this new and dangerous land.
For Sakura, she could be a healer in the Game of Thrones world. With her medical ninjutsu skills, she could treat the wounded from dragon attacks or battles. And she might also learn some of the local magic to enhance her healing abilities, all while having to deal with the political intrigue and power struggles that are so common in the Game of Thrones universe.
Well, modern technology in a Game of Thrones fanfiction would completely disrupt the power dynamics. Consider the Internet. If Westeros had the Internet, knowledge would spread like wildfire. People would be able to learn about different cultures and ideologies quickly. This could lead to the rise of new political movements. In terms of warfare, drones could be used for surveillance or even as weapons. It would be a strange sight to see a Lannister army being monitored by a drone from afar. And imagine the shock on people's faces when they first see a tank roll into King's Landing.
Jon Snow was exiled to the Night's Watch again after killing Daenerys. Arya Stark set sail to explore the unknown west. Sansa Stark became the Queen in the North, ruling independently. Tyrion Lannister served as the Hand of the King to Bran Stark.
Well, Naruto's ninja skills would be quite a shock in Westeros. He could use his shadow clones to spy on different houses or in battles, creating a huge advantage. His chakra control might be seen as some sort of magic. Maybe he'd team up with the Starks, teaching them some of his techniques to fight against the Lannisters or the White Walkers.