Barry and Iris are the main ones. Barry, with his super - speed abilities, and Iris, the smart and resourceful journalist. Their baby is the focus of the story. Additionally, characters like Joe, Iris's father, might be involved. He could be the doting grandfather, giving advice on raising the baby and also being there to support the family when things get tough in the fanfiction world.
Main characters are Barry, a speedster, and Iris, his wife. Their baby is a key character. But also, villains from the Flash series could be part of it. For instance, if there's a villain who wants to get to the baby for its powers, that villain becomes an important character in the fanfiction. And then there are friends like Cisco Ramon, who might use his engineering skills to create things to protect the baby or help it develop its powers in a safe way.
The main characters are obviously Barry and Iris, who are the parents. And of course, their baby is a central character as well. There might also be other characters from the Flash universe like Cisco and Caitlin who could play important roles, like helping Barry and Iris take care of the baby or dealing with any threats that come up because of the baby.