Often, the Gravewalker themselves is a main character. They usually have a mysterious past and special abilities. There could also be characters from the original Game of Thrones series who interact with the Gravewalker. For example, Jon Snow might cross paths with the Gravewalker and they could form an alliance or be at odds. Daenerys could also be involved, perhaps seeing the Gravewalker as a threat to her claim to the Iron Throne.
Well, the idea of a Gravewalker in Game of Thrones fanfiction can bring in the concept of a different form of magic. It's not like the regular fire - based or blood - based magic we see in the show. This new form of magic related to the dead could potentially have a connection to the White Walkers in some fanfictions. Maybe the Gravewalker has the ability to control or at least influence the White Walkers in a way. It could also be that the Gravewalker is a key to unlocking some ancient secrets about the First Men and their relationship with death and the afterlife.
Since I don't know the exact 'naruto gravewalker fanfiction', it's hard to say for sure. But it could feature Naruto himself as a main character, perhaps he discovers the world of the gravewalker. Or it could be an original character created for this fanfiction who is the central 'gravewalker' figure.
The Gravewalker is obviously a main character. They are the central figure around which the story revolves. Then there could be Harry Potter himself. Since it's a fanfiction set in the Harry Potter universe, Harry might interact with the Gravewalker, either as an ally or an adversary. Hermione and Ron could also be involved, depending on how the story is crafted.
It could be a new character created specifically for the fanfiction. This character might be an outcast from a noble house who receives the call and is thrust into the center of the power struggles in Westeros.
In some fanfictions, Jon Snow could be a central figure when combined with the angel elements. Imagine an angel bestowing upon Jon some new powers or knowledge that helps him in his fight against the White Walkers. And there could be a female angel character who has a special bond with Jon, guiding him not just in his battles but also in his personal growth as a leader.
Often, there could be a young and idealistic character who leads the uprising. Maybe a bastard son or daughter of a noble house who has seen the injustice in the system. Another could be a former slave who has escaped and now wants to free all his fellow slaves. And there might be a maester who has been exiled from the Citadel for his radical ideas and joins the uprising.
A young and clever maid in the service of one of the noble families in Queensgate could be a main character. She might be privy to a lot of secrets and use her wits to navigate the dangerous political waters. Maybe she overhears a plot against her master and has to decide what to do about it.
One main character could be a genetically - enhanced human who has special abilities, like Arya Stark's skills in the original. She could be on a mission to avenge her family who were killed by a powerful space - faring clan. There could also be a powerful warlord from a distant star system, a bit like Ramsay Bolton, feared for his cruelty and thirst for power. The interactions between these diverse characters would drive the story forward in this space - based Game of Thrones fanfiction.
Cinderella would be a central figure. For the male lead, it could be a young and noble - hearted character like Robb Stark. He has the charm and leadership qualities similar to a prince. The stepmother could be a power - hungry noblewoman, like Cersei Lannister in some ways. The stepsisters could be her daughters, who are jealous of Cinderella's beauty and the attention she gets from the young lord. And then there could be other 'Game of Thrones' characters like Tyrion Lannister as a side character providing some wisdom and humor.
Myrcella is obviously one of the main characters. Since it's a fanfiction centered around her, she would be the focal point of the story.