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.
Happy could be a fun supporting character. He could fly around and fetch things for Lucy when she can't move around easily during the pregnancy. Wendy could also be involved, using her healing magic to check on Lucy's and the baby's health from time to time.
The plot could involve Gray and Lucy dealing with the challenges of pregnancy. For example, Lucy might have a difficult pregnancy with some health scares. Gray would be by her side, using his ice magic to keep her cool during hot flashes. Their friends might be concerned and offer different kinds of support. In the end, they welcome a healthy baby into the world.
Another character who could interact with them is their guild master. He could be concerned about how this pregnancy will affect their ability to take on jobs and contribute to the guild. He might offer some sort of support or special arrangements for them during Lucy's pregnancy. And of course, there could be some side characters from their world who interact with them in different ways, like the local merchants who provide baby supplies.
Well, it could start with Gray and Lucy being on a really dangerous mission together. In the midst of all the chaos and life - threatening situations, their emotions run high and they end up getting closer than they ever thought. Later, Lucy discovers she's pregnant. Gray then has to step up and be more responsible. They might face challenges like financial difficulties as they prepare for the baby. And there could be a sub - plot where they search for a safe place to raise their child away from the constant danger of their guild life.
Maybe the story could focus on Lucy's journey during the pregnancy. She could be dealing with morning sickness and hormonal changes while Gray is away on some important mission. This could lead to some misunderstandings between them, but in the end, they come closer together when Gray realizes how much Lucy needs him.
Bellatrix could be a supporting character. She might have a complex reaction to Narcissa's pregnancy. On one hand, she could be happy for her sister, but on the other, her loyalty to Voldemort and the dark arts could make her view the new life as a potential weakness or a distraction. Another supporting character could be Narcissa's maid or house - elf. They would be there to take care of her needs during pregnancy, like preparing special meals and making sure the house is in order for the baby.
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.
Gray's character development could be quite significant. He might start to show his softer side more often. Usually, he's all about the ice - cold exterior, but now he has to think about a family. He could become more of a family man, putting Lucy and the baby's needs above his own. For Lucy, she'd grow in confidence. She'd have to be strong for the baby, and this would make her more assertive in the guild. She might also start to take on different roles, like teaching the younger members about family values that she's learning herself.
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.
Gray and Lucy's pregnancy could be a beautiful journey. One day, Lucy discovers she's pregnant. Gray is initially shocked but then filled with joy. They start preparing a small nursery in their home. Gray paints the walls blue while Lucy arranges the baby furniture. Their friends from Fairy Tail are excited too, constantly bringing gifts and offering help.
Hermione would definitely be a major supporting character. She'd be using her vast knowledge to help Harry throughout the pregnancy.