His parents or adoptive parents in the Cullen family are likely to be main characters as well. They would be responsible for taking care of baby Edward, so they play an important role in the fanfiction.
Depending on the specific plot, other members of the Cullen family could also be main characters. They might interact with baby Edward, teach him things, or have their own reactions to his presence in the family as a baby.
One possible plot could be about Edward Cullen's early days as a baby vampire. Maybe he shows some unique powers even as a baby in diapers, like being able to communicate telepathically with his family in a very basic way. Another could be his relationship with his parents in this infant state, how they take care of him and his special needs.
Often, antagonists are also important characters in jasper hale and edward cullen fanfiction. These could be rival vampire clans or individual vampires with malicious intents. They create conflict for Jasper and Edward, forcing them to use their powers and work together. The presence of these antagonists can drive the plot forward and also show different aspects of Jasper and Edward's personalities as they face these threats.
One great 'baby Edward Cullen fanfiction' is 'Edward's Early Days'. It beautifully portrays his character as a baby in a very innocent way.
A possible theme could be family. If Edward is in diapers, his family would have to take care of him. This could explore the family dynamics in a different way. For example, how Esme would mother him in this state, or how Emmett would tease him but also protect him. Also, the theme of adaptation could be there. Edward would have to adapt to this new form and the limitations it brings, like not being able to move as freely as he used to.
One possible storyline could be a humorous take on Edward Cullen being turned into a baby vampire. Maybe he still has his vampiric powers but is in a diaper, which would lead to some comical situations like trying to hunt while waddling around in a diaper. Another could be a time - travel or spell - gone - wrong scenario where he's reverted to an infant - like state, and his family has to take care of him, all while he has his normal Edward - like thoughts and feelings.
Family unity is also a big theme. The Cullen family comes together to support Edward, Bella and the new baby. They all contribute in different ways, like Carlisle with his medical knowledge and Esme with her motherly care, to ensure the well - being of the baby and the family as a whole.
Perhaps a mysterious stranger. This stranger could have some connection to the reason why Edward turned into a baby. And then there's Edward's pet dog. The dog might be confused at first but then becomes very protective of baby Edward, adding an interesting dynamic to the story.
The baby would also be a significant character, even if it might start as a newborn. Its presence changes the dynamic between Bella and Edward and influences the actions and decisions they make throughout the fanfiction. And depending on the plot, other characters like Jacob or members of the Cullen family could also play important roles. For example, Carlisle might be involved in providing medical knowledge about the unique situation of the baby. Or Jacob could be there to offer protection from the werewolf side, given his connection to Bella and his pack's loyalty.
Edward, of course, would be one of the main characters. And there could be a female character, like Isabella, who might be Edward's love interest and the potential mother of his baby. Maybe there's also Edward's best friend, Jacob, who gives him advice on this journey of wanting a baby.
Obviously, Edward and Bella are the main characters. They are the parents in this fanfiction. And of course, their baby is also a very important character, even though it may not have a name yet in some versions of the fanfiction.