king of Westeros

Well, one possibility is that Naruto uses his ninja skills in the world of Westeros. He might use his shadow clone jutsu to confuse his enemies in battles against the knights or rival houses. Maybe he forms an alliance with a particular house using his charisma, like he did with his friends in the Naruto world.

The White Walkers could be major antagonists. Naruto would have to use his skills to combat their undead hordes. Their magic is very different from the chakra - based abilities Naruto has, so it would be a great challenge.

A Spartan would likely find it tough to fit into Westeros' social hierarchy at first. They come from a society where merit and combat ability are highly valued. In Westeros, birthright often determines one's position. However, their combat skills might earn them respect among the military. For example, they could quickly rise through the ranks in a lord's army.

Naruto would probably find the social hierarchy in Westeros quite strange at first. But his friendly and adaptable nature would help. He might start at the bottom, but his skills would quickly earn him respect. He could become a sort of outsider hero, not fully bound by the strict rules of the hierarchy.

The fem Harry Potter could also change the power balance. If she aligns herself with a particular house, that house would gain an edge. Her knowledge of magic could be used to uncover secrets in Westeros, like hidden passages in castles or ancient prophecies that were previously unknown. This new information would disrupt the existing plans of the different factions vying for the Iron Throne and other power positions.

Obviously, Harry is one of the main characters. He brings his Hogwarts - trained magic and his own personality to the world of Westeros.

In a Westeros fanfiction with Tony Stark, he could potentially form alliances. For example, he might team up with Daenerys Targaryen. His knowledge of engineering could help her build better defenses for her cities, or even improve the design of her dragons' saddles. Also, his charisma and leadership skills could influence the political landscape of Westeros in unexpected ways.

Fanfiction.net is also a good place to search. It has been around for a long time and has a significant amount of content related to Westeros. Just use the search function and type in relevant keywords like 'Westeros watches' to find what you're looking for.

One great Westeros watches fanfiction could be those that explore the backstories of the various watch members. For example, a story about how a particular ranger joined the watch and his early adventures on the Wall.

In fanfiction, 'Harry Potter changes Westeros' could be through his magic skills. For example, his spells like Wingardium Leviosa could be used to move heavy objects in Westeros, which might change the way battles are fought or construction is done. His knowledge of the magical world could also introduce new concepts to the people of Westeros.