Often in such fanfictions, there will be an antagonist as well. This could be a power - hungry entity in the twilight world who doesn't want the main character to succeed in using their wishes for good. The main character could be a person with a kind heart who is trying to bring positive change to the twilight realm. There might also be some side characters, like the main character's friends from their past life who are somehow connected to the new world and play important roles in the story.
Edward Cullen is often a popular choice. His brooding nature and vampire abilities make for interesting storylines. Writers can explore his character further, like how he would react if he was reborn with different memories or emotions.
One idea could be a new vampire character being reborn in the Twilight universe with a special power, like the ability to control the weather. This would create a whole new dynamic as they interact with the Cullens and other vampires.
One interesting plot could be the main character being reborn with some unique powers that they didn't have before. For example, they might be able to control the elements in the twilight world, which leads to all sorts of adventures and challenges as they try to use their powers for good. Another plot could involve the character making wishes that have unforeseen consequences. Maybe they wish for a peaceful world, but in doing so, they accidentally disrupt the natural balance of the twilight realm.
One plot possibility could be that the male OC is reborn as a vampire. He might struggle with his new existence, having to adapt to the vampire lifestyle in the Twilight universe. For example, he could have a hard time dealing with his bloodlust while also trying to fit into the complex social structure among the vampires. Another possibility is that he is reborn as a human with some sort of special ability. Maybe he can sense the presence of vampires and werewolves before anyone else, which then draws him into the dangerous world of the Twilight saga. He could end up being a key figure in the ongoing feud between the two supernatural groups.
Well, he might bring his magical skills into the world of vampires and werewolves. Maybe he'd use magic to deal with the complex relationships between the Cullens and the werewolf pack. He could also introduce new magical elements to the Twilight world, like potions to counteract vampire venom or spells to protect humans from vampire attacks.
If he's reborn as a vampire, his relationships would be drastically different. He might form new alliances with some vampires while being in conflict with others. For example, he could befriend Carlisle Cullen due to his kind nature, but be at odds with the Volturi. As for relationships with humans, he would have to hide his true nature, which could lead to some complex and strained relationships. He might be drawn to Bella Swan because of her connection to the vampire world, but also have to keep his distance to protect her.
His character would probably become more complex. He'd have to adapt to a world without wizards at first. He might start off being cautious, but as he discovers the powers and politics of the Twilight world, he'd grow bolder. He could use his intelligence and magic to his advantage.
Twilight in this fanfic still serves as the backdrop. It provides the familiar world and characters that readers of the original series know. However, the 'tumor' aspect added to Edward's story might put a new spin on the Twilight elements. For instance, the vampire - human relationships which are central to Twilight could be affected by Edward's condition.
Yes, it is a bit strange. After all, they are the ones living the story, and fanfiction is often a creative interpretation by outsiders. It's like they are stepping into a parallel world where others have reimagined their lives.