There could be some characters from outside the North as well. For example, a wandering knight who is impressed by Harry's courage and Stark - like qualities. Or perhaps a foreign noble who has heard of the Starks' reputation and sees Harry as a means to gain influence in the Westeros. These unexpected allies could bring new perspectives and resources to Harry's cause.
In the normal 'Harry Potter' and 'Game of Thrones' universes, there is no such connection. But in some wild and creative fanfiction, it could be possible. Fanfiction often bends and twists existing universes to create unique and unexpected relationships. However, this is not part of the official lore of either series.
In the fanfiction, Harry might find allies among the ghosts in Hogwarts. Since he is the son of Hades, he could have a special connection with them. They could provide him with information and support. Another potential group of allies could be the outcasts in the wizarding world. People who have been shunned or misunderstood might be drawn to Harry because they see him as a fellow outcast due to his new identity. And there's also a possibility that some of the more rebellious students at Hogwarts, who are not afraid to go against the norm, would become his allies and help him face the challenges that come with being the son of Hades.
One potential ally could be Hagrid. Hagrid has always been a friend to Harry, and in this fanfiction, he could help Harry understand his newfound heritage as the son of Hephaestus. Hagrid's knowledge of magical creatures could also be useful in Harry's adventures related to his Hephaestus - given abilities.
Hermione would definitely be one of his allies. She is smart and would be able to help him research about his new identity and how to control his powers. For example, she could find ancient texts in the Hogwarts library that relate to both the wizarding world and the Greek gods.
In this fanfiction, some of the potential allies for Harry could be the magical creatures that have a connection to Norse mythology. For example, the Valkyries. They could help Harry in battles or in understanding his new heritage. Another ally could be Odin, Frigga's husband. Despite the initial shock of Harry's existence, he might see the value in Harry and offer his protection and guidance. And don't forget Neville. He's always been a loyal friend to Harry, and in this new scenario, he would continue to be an ally, perhaps even more important as Harry faces new and different challenges.
His friends from Hogwarts could still be his allies. Hermione would use her intelligence to help him understand his new situation. Ron would be there for moral support. Additionally, any friends or allies that Rias has in her world could also become Harry's allies. They might be magical creatures or other powerful mages.
Hermione would definitely be an ally. She's smart and would be able to help Harry research about his 'son of Mars' heritage, finding ancient spells or texts that could explain it further.
Dumbledore could be a powerful ally. He has a deep understanding of magic and would be interested in exploring Harry's new abilities. Also, some of the more open - minded members of the Order of the Phoenix might see the potential in Harry's unique heritage and support him, like Lupin or Sirius if they were still alive in the fanfiction.
If in fanfiction Harry Potter was Brandon Stark's son, it would create a very strange and interesting mix of magic and medieval politics. The wizarding world of Harry Potter has its own set of rules regarding magic and society, while the world of Brandon Stark is filled with power struggles, wars, and complex family dynamics. There would be a clash between the two cultures. For example, how would the people of Westeros react to magic? And how would the wizarding world view the violent and often cruel world of Westeros? It would be a wild ride for the story.
Another storyline could involve Harry being trained in both magic and combat skills by Tony. They could team up to fight villains from both the wizarding world and the Marvel universe. Harry could use his magic to counter the superpowers of Marvel villains while Tony provides the technological backup.