The father of the baby could be a major character. He could be a loving partner, or there could be some drama if he's not as committed as Lucy. Her best friend could also be in it. The best friend might be the one she confides in about all her pregnancy fears and joys.
Lucy's mother could be an important character. She could offer her own experiences and advice to Lucy. There could also be a nosy neighbor who is always trying to get the latest scoop on Lucy's pregnancy. And perhaps a doctor who takes care of Lucy throughout her pregnancy, providing medical advice and reassurance.
A midwife or a doctor in the area where Lucy ends up could be a main character. Since she's pregnant, she'll need medical assistance. This character could be kind and understanding, providing not only medical help but also emotional support. And then there could be a local villager who initially suspects Lucy but then becomes her ally as they get to know her story.
There could be a young wizard named Tom. He might be Lucy's sidekick or someone she mentors. He could have his own set of magic skills that complement Lucy's dragon powers. Another character could be an old dragon sage named Zoltar. He might be the one who gives Lucy advice and wisdom about her role as the dragon goddess.
Erza could also be a main character. Given her strong and motherly side, she would probably take on the role of taking good care of baby Lucy. She might be strict about following a routine for baby Lucy's care. Happy, the flying cat, could be another important character. He could use his unique abilities to search for clues on how to turn Lucy back to normal.
The baby's father, whoever he is, could be another main character. He might be a mysterious figure at first, and as the story progresses, his identity and his relationship with Lucy get explored more deeply. He could be a guy from Lucy's past that she has complicated feelings for.
It could be a heroic character she meets during her quest. Maybe a powerful wizard or a brave knight who has a brief but intense encounter with Lucy, leading to her pregnancy.
Her best friend could be important. The friend might offer emotional support, babysit sometimes, or give Lucy some parenting tips that she learned from her own family.
Well, one possible plot could be about Lucy's journey through her pregnancy. Maybe it focuses on how she prepares for the baby, like decorating the nursery. It could also show her dealing with the physical and emotional changes. For example, she might be excited but also a bit scared at the same time.
Erza could be a great supporting character. She might offer her strength and protection to Lucy during the pregnancy. Natsu could also be there, being his usual boisterous self but also showing a caring side towards the expecting couple.
Gray could also be a possibility. He and Lucy have a friendly rivalry and there are moments where their relationship could be interpreted as having deeper feelings. It would be an interesting twist if Gray was the father, as it would change the dynamics between him, Natsu, and Lucy in the fanfic.
One character that would be interesting to include is Mirajane. She has a motherly and observant nature. She could be the one to nudge Natsu and Lucy in the right direction when it comes to their relationship. For instance, she might arrange for them to go on a mission together that she knows will bring them closer. Laxus could also be in the fanfiction. His powerful presence can create a sense of danger or protection. If there's an outside threat to the guild while Natsu and Lucy are exploring their relationship, Laxus could be at the forefront of defending the guild, which would impact Natsu and Lucy's situation. And don't forget about Cana. She could be the one to create some light - hearted chaos, like daring Natsu and Lucy to do something that ends up bringing them closer, such as a bet that leads to a shared adventure.