Simon's character can be developed by exploring his backstory. If he has a troubled past, it can be revealed gradually as he gets closer to Bella. Also, his relationship with Bella can make him more empathetic or more guarded depending on how their interactions play out. For example, if Bella is initially suspicious of him, he might become more defensive in his behavior.
You can develop their characters through their shared experiences. Let's say they go on a journey together to find a cure for a new disease that is affecting both humans and supernatural beings in Forks. During this journey, Bella can become more courageous as she faces new challenges, and Simon can show his loyalty and determination to protect Bella and find the cure.
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.
One way is to explore the backstory of Petrova more deeply. If Bella is a fan, then showing what makes Petrova so fascinating to her through detailed backstories would be great.
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 story could be developed is by having Bella be a secret Mikaelson fan in the Twilight universe. Maybe she discovers a hidden book about the Mikaelsons in the Forks library. This could lead to her having strange dreams about them and it might even influence her relationship with Edward. For example, she could start comparing Edward's vampire nature to that of the Mikaelsons.
Their relationship can be developed through shared experiences. For example, they could face a common enemy together. This would force them to rely on each other and understand each other's strengths and weaknesses.
In fanfiction, their relationship might develop through a series of adventures. Suppose they go on a quest to find a rare artifact that has the power to either save or destroy the vampire world. Along the way, they face numerous challenges like dangerous terrains and other powerful vampires. During these hardships, they start to care for each other more. Peter might show his protective side towards Bella, and Bella might be the one to give Peter hope and a new perspective on life. This would strengthen their bond.
One popular Bella Swan and Simon Lewis fanfiction is 'Unexpected Alliances'. It explores a unique scenario where Bella and Simon team up against a common supernatural threat in a world that combines elements from their respective fictional universes. It has great character development and an engaging plot.
A plot could revolve around Simon being a long - lost relative of Bella's. He shows up in Forks and his presence disrupts Bella's relationship with Edward. Simon has his own secrets about the supernatural world which Bella gradually uncovers, and she has to decide between the two different worlds she's now a part of.
A well - crafted plot that combines the two different universes is key. It could involve how their different supernatural worlds interact, like the vampires in 'Twilight' and the demons in 'Shadowhunters'. Maybe a situation where they have to use their unique abilities to solve a problem that spans both worlds.
In fanfiction, to develop Sam, you could give him a unique skill like being able to communicate with animals. This would add an interesting layer to his character. He could share his experiences with Bella, and it would be a special bond between them. For Bella, you could explore her dreams and aspirations. If she wants to travel the world, Sam could be the one who encourages her and they could plan imaginary trips together, which would deepen their connection.