It could be a young couple who are still in college. They have to balance their studies, part - time jobs, and the upcoming baby. It would be a story of their struggle and growth.
Obviously, Tiffany Valentine would be one of the main characters. The baby would also be a central figure. There could also be her friends or foes from the original story that interact with her during this new phase of her life. For example, if she has a long - time enemy, they might try to use the baby against her.
It could be Hinata. Since they are in a relationship in the original series, it would be a natural choice. Hinata would be a loving and caring mother, and her gentle nature would be a great influence on the baby.
It could be that the baby is an alien baby who crash - lands on a planet where the beast is the dominant species. The beast might be a huge, furry mammal - like creature.
The main characters would obviously be the five Avengers. It could be Iron Man, Captain America, Thor, Black Widow, and Hulk. And of course, the baby would be a central character as well. Maybe the story could focus on how each of the Avengers interacts with the baby differently. For example, Iron Man might use his technology to create baby - friendly gadgets, while Thor might tell the baby stories of Asgard.
Another option could be a completely new character created just for the fanfiction. This new character could be a powerful unicorn or an alicorn from a far - off land who met Twilight during one of her adventures and they fell in love.
The First Evil could also be a great antagonist. It could try to corrupt the baby, seeing it as a new vessel to spread chaos. Since the baby would be part of Buffy and Faith, it would be a prime target for the First Evil's schemes.
Obviously, Sonic himself would be a main character, even in his baby form. His friends like Tails, Knuckles, and Amy would also be main characters. Tails could be the one trying to figure out how to turn Sonic back. Knuckles could be the protector, and Amy could be the caretaker.
Obviously, Voldemort as a baby would be one of the main characters. Harry Potter could also be a main character as he has a long - standing enmity with Voldemort. He might be involved in deciding the fate of the baby - voldemort. Dumbledore would surely play a major role. His wisdom would be needed to deal with this strange situation. And Hermione, with her vast knowledge of magic, could be involved in trying to find a way to either reverse the transformation or ensure that the baby Voldemort grows up to be good.
Obviously, Ash would be a main character even in his baby form. Pikachu is bound to be a key character as well, being Ash's closest Pokémon partner. His other Pokémon like Bulbasaur, Charmander, and Squirtle could also play important roles in protecting and taking care of baby Ash.
Obviously, Nightwing himself, even as a baby, would be a main character. His friends in the Bat - family like Batman, Robin, and Oracle would also be main characters. They would be the ones dealing with the situation of baby Nightwing.