Well, Dovahkiin's Thu'um is a very distinct form of magic. In Middle - earth, it could be considered a very primal and powerful magic. It doesn't seem to rely on the same sources as the magic in Middle - earth. But it could be seen as a force of nature, much like some of the more ancient and powerful magics in Middle - earth.
Dovahkiin's ability to learn dragon shouts and gain new powers from them could be similar to how wizards in Middle - earth study and gain new magical abilities. However, his magic is more physical in a sense. When he shouts, it has a direct impact on the environment and those around him. In Middle - earth, most magic is more subtle. So, it would be an interesting contrast and might cause some confusion or even fear among the inhabitants.
The way Dovahkiin's magic is tied to his dragon - related experiences is unique. In Middle - earth, there are no dragons in the same sense. So, his power might be seen as something completely foreign. But perhaps the elves, with their long knowledge of magic, could start to understand and even try to incorporate some aspects of the Thu'um into their own magical practices, or at least study it to gain an advantage against Sauron.
In a Dovahkiin x Lord of the Rings fanfiction, Dovahkiin could also explore the different cultures of Middle - earth. He might be intrigued by the elves' grace and knowledge. And his presence could potentially change the course of the war against Sauron. For instance, his dragon - riding skills could give the good guys an edge in aerial battles, if there were any in the story.
The dovahkiin's dragon shouts would be a huge advantage. For instance, his 'Unrelenting Force' shout could clear paths through enemy lines. This would make it easier for the fellowship to move forward in dangerous terrains filled with enemies.
Well, Naruto's immortality would give him an edge. His ninja skills like shadow clones could be used for various tasks in Middle - earth. For example, he could send clones to scout out Mordor while the Fellowship tries to figure out a plan. His Rasengan might be a new and powerful weapon against the orcs and other dark forces. And his ability to endure and keep fighting without getting tired would be very useful in the long battles against Sauron's minions.
Sasuke's Sharingan would be a great asset. It could help him see in the dark, which would be useful in places like Moria. His ability to copy other people's fighting styles could also come in handy when facing different foes in Middle - earth. And his speed and agility would make him a formidable opponent in battles against orcs or other evil creatures.
Well, Alex Mercer has some amazing powers like shape - shifting and super strength. In Middle - earth, his shape - shifting ability could be both a boon and a bane. He could potentially shift into the forms of various creatures in Middle - earth, which might give him an edge in certain situations. For example, he could shift into an eagle to gain a better view or into a bear to fight off enemies. However, his powers might also be seen as a threat by the native beings of Middle - earth, who might not understand such abilities. His super strength could also be useful in battles against the forces of Sauron. He could easily take on orcs and trolls, but he would have to be careful not to draw too much attention to himself as an outsider with such strange powers.
The Dovahkiin in Game of Thrones fanfiction would bring a whole new element of magic. GOT has some magic, but the Dovahkiin's magic is more direct and powerful. Their ability to understand and communicate with dragons would make the dragons in GOT seem more intelligent and less like just wild beasts. This could lead to new alliances. For instance, Daenerys might be both intrigued and threatened by the Dovahkiin. She might try to either make an ally of them or eliminate them as a rival. And the Dovahkiin would probably have no interest in the Iron Throne itself, but more in the challenges and foes that GOT presents, like the White Walkers. They would see the White Walkers as a worthy enemy to test their skills against.
The Dovahkiin could be a protector in a Game of Thrones fanfiction. With their great strength and powers, they might safeguard the innocent from the horrors of war, like the smallfolk who are often caught in the crossfire in GOT. They would not side with any particular house just for political gain, but rather help those in need.
Blake could be a bit of an enigma in Middle - earth. She might have some similarities to the Rangers, as she is used to being on her own and is very stealthy. Her faunus heritage could also add an interesting dynamic, as she could have some unique abilities that are different from the normal races in Middle - earth. Yang, with her strength and courage, would be a great addition to any battle. She could be like a female version of Gimli, always ready for a fight and not afraid to take on powerful enemies.
Sakura is determined. In a Lord of the Rings fanfic, this would serve her well. Just like Frodo was determined to destroy the ring, Sakura could be determined to achieve her own goals in Middle - earth, whether it's helping to defeat Sauron or something else.
Naruto's speed and agility from his ninja training would make him a formidable fighter in Middle - earth. He could quickly move around the battlefield, dodging arrows and attacks from orcs and other enemies.