The brother's character could be developed as a curious explorer. Since Forks is a new place full of secrets, he could be eager to learn about its history and the surrounding forests. This could lead him to discover the werewolf pack's territory on his own or find out about the ancient vampire legends in the area. His inquisitive nature would then draw him deeper into the supernatural elements of the story, changing the course of the fanfiction.
Well, the brother could have a completely different reaction to Forks compared to Bella. He might hate the rain and constantly try to find ways to escape the small town. Or he could be really into the outdoorsy stuff in Forks, like hiking in the forests, which could put him in danger as there are vampires and werewolves lurking around. Maybe he even stumbles upon some secret vampire lair by accident.
One possibility could be that his move to Forks sets off a chain of events related to the supernatural elements already present there. Maybe he discovers secrets about the vampires and werewolves that Bella is involved with and has to navigate this new world while also trying to protect his sister.
Bella Swan's character could be developed by having her explore different aspects of herself. In the context of Greek gods, she might discover a more passionate side of herself, like the passion associated with the Greek concept of eros. This could make her more confident and change her relationships. She could also be developed through her experiences with the Greek gods' powers. If she gets a taste of Athena's wisdom, she could use it to solve problems in Forks that she couldn't before. This would make her a more respected and important figure, not just among the Twilight characters but also among the Greek gods she encounters.
One way the storyline could be is that Percy uses his demigod powers to protect Bella from the various threats in Forks. For example, he could sense the presence of vampires and werewolves before Bella does and keep her out of harm's way. He might also introduce her to the world of Greek mythology, which would be a huge contrast to the world of Twilight she already knows.
The half - brother could be developed as a character with a troubled past. He might have been ostracized in his own community because of his relation to Naruto or his own unique abilities. This could make him initially cold and distant but as he interacts with Naruto, he could gradually open up and become more warm - hearted.
To develop Bella in this fanfiction, she could be given a mentor. Maybe an old witch who has been watching over her. With the mentor's help, she can learn about the history of doppelgangers in the witch world and how to control her powers. She can also struggle with the morality of using her powers, like whether she should use them to get revenge on those who have wronged her in the past.
Percy's relationship with Jacob could also be a key part of the story. They might initially be at odds because Jacob is a werewolf and Percy is used to dealing with different kinds of 'creatures'. But over time, they could learn to work together, especially if they both have Bella's best interests at heart. Percy's interactions with Bella herself would be a mix of brotherly love and trying to keep her out of supernatural trouble.
First, his character could start off as a bit of an enigma. Maybe he has been away from Hermione for a while, and when he returns, he realizes how much she needs protection. As the story progresses, he could show his protective side more and more. He might be a strong wizard, but also have a soft heart, especially when it comes to Hermione. He could be developed as someone who is well - respected in the wizarding community for his own achievements, and uses that status to shield Hermione. For instance, if she's wrongly accused of something, he uses his influence to clear her name. He could also have a bit of a temper when it comes to those who threaten Hermione, which adds an interesting dimension to his character.
He could be developed as a skilled healer. Since Talisa was a healer in the show, it would make sense for her brother to have some medical knowledge as well. This would allow him to interact with various characters who are injured or ill, and he could use his skills to gain influence or information.
One popular character paired with him is Jessica. In some fanfictions, they start as friends but then develop deeper feelings for each other. Their relationship is interesting because Jessica is so different from Bella, and it shows a different side of Bella's brother.