It could also be that the main wolf - character is a spirit wolf that only certain wizards can see. Harry Potter is one of those wizards. The spirit wolf has a prophecy or some important knowledge related to defeating Voldemort. Harry has to work with the spirit wolf to decipher the message and use it to his advantage. Along the way, they develop a deep bond that changes Harry's perspective on magic and the unseen forces in the wizarding world.
Obviously, Harry Potter himself could be one of the main characters. And for the wolf - related character, it could be a werewolf like Remus Lupin. Lupin could have a more central role, perhaps mentoring a young werewolf student at Hogwarts. Harry could be involved in helping this student along with Lupin, and their combined efforts could form the core of the story.
Well, Harry Potter is bound to be a central figure in this fanfic. The wolf king is another main character. It's possible that other characters from the original series could play important roles too. For instance, Dumbledore might offer some wisdom or guidance regarding the wolf king. Or perhaps some of the darker characters like Voldemort's followers could be interested in the power of the wolf king and try to get in Harry Potter's way as he deals with this new entity. Neville could also be a character in this fanfic, showing his growth and courage as he helps Harry Potter face the challenges related to the wolf king.
Hermione Granger would make an excellent main character too. Her intelligence and knowledge of magic would be very useful in a crossover scenario. She could analyze the rules of the Hunger Games - like event and come up with strategies. And Peeta Mellark could be another main character. His charm and ability to form alliances could be important, especially when dealing with the complex social dynamics in a combination of the two universes.
One possible plot could be a werewolf in the Harry Potter world who is trying to hide their identity at Hogwarts. Maybe they are a student who has to deal with the monthly transformations while also trying to keep up with their studies and avoid suspicion from the teachers and other students. They could form an unlikely friendship with Harry Potter, who helps them keep their secret and in return, the werewolf uses their unique abilities to assist Harry in his battles against the dark forces.
It could be a new dark wizard who has somehow tapped into the power of both the wizarding world and the Narnian magic in a negative way. This wizard might want to rule both realms and is using dark magic from both to achieve his goals.
You could have a new generation of witches and wizards as the main characters. For example, the children of the original trio. They might be visiting the manor for the first time and discover something that their parents had missed. There could also be a misfit wizard who finds a sense of belonging at the manor, and his story could be the focus.
In a 'harry potter inquisitor fanfic', the main characters could include the Inquisitor, who is the central figure driving the investigations. Then there could be a new character, an exchange student from a far - off magical school. This student has a different approach to magic and catches the Inquisitor's eye. Additionally, Professors Snape and McGonagall could be main characters. Snape might be secretly working against the Inquisitor if he thinks their actions are unjust, while McGonagall could be trying to keep the peace between the Inquisitor and the students. The interactions between these characters would create a rich and engaging story.
Fred and George Weasley could be the main characters in a new business adventure. Maybe they expand their joke shop business to include international locations. They could come up with new products that are suitable for different wizarding cultures. For example, they might create a line of magical fireworks that are designed to celebrate different wizarding holidays around the world. They would have to deal with the challenges of international trade in the wizarding world, like different magical regulations and cultural taboos.
In a 'Harry Potter Windsor fanfic', the main characters could include Ron Weasley. He could bring his humorous and sometimes clumsy nature to the interactions with the Windsor family. Also, an older member of the Windsor family, like the Queen (in a fictional magical version), could be a main character. She could be the one who is initially skeptical but then comes to accept the existence of magic. And Dumbledore could play a role as the wise guide in any magical matters involving the Windsors.
Hermione Granger could also be a main character. With her intelligence, she would be quick to learn ninja techniques and could even help improve them with her knowledge of magic. She might study the ancient ninja scrolls and find ways to combine the knowledge of both worlds for the greater good.
Harry Potter himself could be a mutant in the fanfic. He might discover he has mutant powers on top of his wizarding abilities, like the power to heal without using magic spells. This would make his character even more complex and powerful.