Bella would likely be more independent. In Twilight, she often relied on others like Edward or the Cullens. In a Z Nation fanfiction, she'd have to fend for herself a lot more. She'd learn to use weapons and be more self - sufficient in finding food and shelter.
She would be more hardened. In the Twilight world, she was mainly dealing with the supernatural in a relatively civilized setting. In Z Nation, she'd have to be tougher to survive the zombie - filled chaos. So she might be less naive and more street - smart.
Her relationships would change. Instead of the romantic, often melodramatic relationships in Twilight, in a Z Nation fanfiction, her relationships would be more about survival alliances. She might form bonds with people she wouldn't have considered in the Twilight world, just because they can help her stay alive in the zombie - apocalypse.
There could be many interesting scenarios in such a fanfiction. Maybe 10k, with his survival skills from Z Nation, ends up in the Twilight universe and meets Bella Swan. He could help her in a different way from the Cullens, perhaps using his combat skills against some new threats in Forks.
A more complex fanfiction could involve a crossover of the two universes' viruses. The virus in Z Nation and the vampire virus in Twilight somehow interact. Bella, being in the middle of it, has to figure out how to stop a new, more dangerous threat that emerges from the combination of these two 'viruses'.
They could be friends. 10k, having seen so much death and chaos in Z Nation, might find Bella's somewhat normal life (despite the vampires and werewolves) refreshing. And Bella could be interested in 10k's tales of survival.
She might become more protective. As Silas's sister, she would have a natural inclination to safeguard him, which could make her more assertive.
She would likely become more confident. Knowing she is the daughter of Hades, a powerful god, would give her a sense of self - worth that she might not have had before. For example, instead of being the damsel in distress in her relationship with Edward, she could be an equal partner, using her powers to protect him and his family if needed.
In an army fanfiction, Bella Swan's character would transform in many ways. Her self - confidence would grow exponentially. She was always a bit self - conscious in the original story, but in the military environment, she'd have to believe in herself to succeed. She'd also become more independent. No longer relying on others to protect her as much, she'd be trained to protect herself and her comrades. And her adaptability would improve, being able to adjust to different military bases, climates, and combat situations.
In some fanfictions, Bella's character might become more confident. As an immortal, she no longer has the same fears of mortality. For example, she could be more fearless in facing dangerous situations.
She might become more assertive. As the daughter of Ares, she would inherit some of his war - like traits. So, instead of being the somewhat passive Bella in the original story, she could be more proactive in making decisions and taking action. For example, she may no longer wait for others to protect her but instead take the lead in dangerous situations.
One way is to join Twilight fan groups or forums. Members often recommend good fanfictions. They can give you specific titles or authors to look for. Also, some fanfiction platforms have recommendation sections where you can find stories that are well - liked by other readers.
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.