Well, apart from Bella, there could be a male lead who is the creative director of the 'for him' brand. He could be a strict and demanding professional but also has a soft side. Then there are the makeup artists and hair stylists who are always around Bella during shoots. Also, there could be Bella's agent who is constantly trying to get her the best deals and manage her career. There might be some models from other agencies who are jealous of Bella's rise in the 'for him' modeling world.
There could be a new character introduced. This character could be someone from Bella's past or a completely new entity. Maybe this character has a claim on the person Bella loves, and Bella, being the selfless person she is in this fanfiction, steps aside to let this new character have a chance at love.
There could be Bella's partner in the relationship she is betraying. This character might be a loving and trusting person, which would make Bella's affair even more complicated and morally wrong.
A potential main character could be Bella's best friend. This friend could provide support and a different perspective as Bella navigates her new identity. There might also be a mentor figure for Bella, someone who knows a lot about Elijah's world and can guide her. This could be an old friend of Elijah's or a wise elder in their community.
There could be her friends. For example, Alice might be there. Alice could be trying to calm Bella down during her tantrum, using her calm and composed nature to soothe Bella's anger.
The truck itself could be considered a main character in a sense. It has its own presence and significance in the story.
Obviously, Bella is one of the main characters since it's named after her. There could also be other characters like her agent, fellow models she works with, or a love interest.
She could interact with Elena. Since Elena is a central character in Mystic Falls, their paths are likely to cross. They might start as friends or rivals, depending on the story.
Bella's mother or a close female friend could also be main characters. Her mother could share her own experiences of giving birth and offer practical advice. The close female friend could be there to hold Bella's hand, offer comfort, and maybe even crack a few jokes to lighten the mood during the intense moments of the birth.
Perhaps a new character could be introduced as the hero. A wizard or a powerful human with some extraordinary skills. This new character could be someone who has been observing Peter's actions from afar and decides to step in to save Bella when the time is right.
Edward can be really interesting. His relationship with Bella takes on a new dimension when she's a siren. He has to grapple with his love for her while also being cautious of her new powers. Another character could be Jacob. His loyalty to Bella might be tested as she becomes something different, and he might have his own mixed feelings about her siren side.