Well, their child might inherit Gray's ice - making magic. Since Gray has such strong control over ice, it could be passed down. And maybe also get some of Juvia's water magic, which could combine in interesting ways. For example, the child could create ice sculptures that are constantly being reshaped by flowing water - like magic.
Their child could have powers related to both Gray and Juvia's emotions. Gray often has a cool and collected exterior but deep emotions, and Juvia is very passionate. So the child might have magic that is affected by its own emotions. In a moment of anger, it could freeze everything around it, and when in love or happy, create beautiful ice - water formations like fountains or ice palaces filled with flowing water channels.
Since Gray is often seen as a bit of a lone wolf and Juvia is very determined in her affections, the child could be independent yet very loyal. It would be the type to pursue its own goals but would also stand by its friends and family no matter what. For example, in a battle, it would fight bravely on its own but also make sure to protect those it cares about. And in daily life, it would be okay with doing things alone like Gray, but also have Juvia's eagerness to be around loved ones when possible.
In many fanfictions where Gray confesses to Juvia, it's often a very emotional moment. It might happen after a big battle where they realize how much they mean to each other. Gray could finally admit his feelings that he has been suppressing for a long time. Maybe he sees Juvia in danger and that makes him realize he can't hide his love anymore.
One possible storyline could be that Gray and Juvia are excited about the pregnancy but also nervous. Gray might be worried about being a good father, as he has had a somewhat troubled past. Juvia, on the other hand, is overjoyed and starts preparing for the baby right away. They could face challenges like finding a suitable place to live as a family, and also dealing with the reactions of their friends in Fairy Tail. Maybe some of their friends are super supportive, while others might be a bit more hesitant or worried for them.
Another reason could be related to his loyalty to the guild. Gray might think that his focus should be solely on protecting Fairy Tail and its members. He could believe that a romantic relationship with Juvia would distract him from his duties. Also, there could be some unspoken guild rules or a sense of propriety that he feels would be violated by getting involved with her.
In fanfiction, Gray's love for Juvia can be portrayed in many ways. Sometimes it's a slow - burn kind of love. Gray, who is initially cold towards Juvia, gradually realizes her importance in his life as she is always there for him, through battles and difficult times.
Well, it could make Gray feel an extreme sense of guilt. He might blame himself for not being able to protect her. And this could lead to him becoming more withdrawn and brooding, perhaps even pushing away his friends as he grapples with the loss.
A great plot might involve Gray and Juvia adopting a child. The child could come from a troubled background and be initially distrustful of them. Gray and Juvia would have to work hard to gain the child's trust. Along the way, they could also teach the child about magic and the importance of family in the Fairy Tail guild. As the story progresses, the family unit grows stronger and they become an inspiration to other members of the guild.
Well, perhaps Juvia might punish Gray for always being cold and distant towards her in a comical way. Maybe she could freeze his clothes every time he ignores her feelings.
Well, in some fanfictions, Gray's love for Juvia is shown through his jealousy. When other guys get too close to Juvia, Gray gets this possessive feeling that he doesn't quite understand at first. It's a sign that his feelings for her are deeper than he thought.
Gray would be devastated. He might go into a state of deep depression, isolating himself from the rest of the Fairy Tail guild. He would blame himself for not being able to protect her, especially if her death was related to her love for him. Gray would probably be filled with anger as well, and he would vow to take revenge on whoever was responsible for her death.