One possible plot could be that Lucy and Juvia leave Fairy Tail to go on a self - discovery journey. They might want to explore their individual magic powers more deeply without the constraints of the guild. Maybe they travel to different magical realms, meet new characters, and learn unique magic techniques that they can bring back to Fairy Tail later.
In the fanfiction, it could be that Lucy and Juvia leave Fairy Tail to find a way to save a friend or loved one. They believe that the guild's resources or approach are not sufficient. So they embark on a dangerous quest. During their journey, they not only grow as individuals in terms of magic but also in their friendship, relying on each other in tough situations.
A powerful magical being from another dimension could be the main antagonist. This being senses the departure of Lucy and Juvia from Fairy Tail and sees it as an opportunity to invade their world. It tries to stop the two girls from getting help or finding a way to stop it, as they are two of the most powerful mages outside of the guild protection now.
It could be that there are some internal issues within Fairy Tail that make her leave while being pregnant. For example, there might be a prophecy or a curse that she believes could harm her baby if she stays. So, in order to break free from that potential threat, she decides to leave. Also, she may be facing some personal conflicts with other members of Fairy Tail regarding her pregnancy, like some not being supportive or having different views on how she should handle it, which ultimately drives her to leave.
One possibility is that the guild would experience a significant emotional impact. Lucy is a central figure, and her celestial spirit magic has been crucial in many battles. Juvia, with her water magic, is also a strong member. Their departure might lead to a decrease in the guild's overall power. Some members might feel betrayed, while others could be motivated to find out why they left and try to bring them back.
It could be a new character introduced specifically for the fanfiction. Maybe a powerful mage who has a vendetta against Lucy and somehow manages to drive her out of Fairy Tail by causing trouble for her within the guild.
A possible reason could be personal conflicts within the guild. Lucy might have an issue with some of the guild's rules or how certain things are run. Juvia could be following Lucy for some reason, like loyalty or because she also has her own issues with the guild. For instance, if there are tensions between Juvia and other members over Gray.
In some fanfictions, Juvia and Lucy could be in a situation where they have to rescue a kidnapped guild member. Juvia uses her water magic to track the kidnapper's location through the moisture in the air. Lucy uses her keys to call upon spirits that can help in combat and stealth. Along the way, they face many challenges and have heart - to - heart conversations. This experience deepens their friendship and they become closer allies within the Fairy Tail guild.
One interesting Juvia Leaves Fairy Tail fanfiction could be one where she goes on a solo adventure to discover her true powers outside of the guild. In this type of fanfic, she might encounter new magical creatures and have to rely solely on her own skills.
A possible fanfiction could be that Juvia leaves to protect the guild. She discovers a dangerous plot against Fairy Tail and decides that her absence would be the best way to keep everyone safe. As she is away, she secretly works to thwart the evil plan, and in the end, she returns victorious, having saved the guild she loves so much.
Perhaps Naruto is on a quest to find a way back to his own world. He realizes that staying in Fairy Tail is only delaying his journey. He has a sense of loyalty to his own friends back home like Sasuke and Sakura. So he leaves Fairy Tail, even though he has made some friends there, in order to pursue his ultimate goal of returning to Konoha.
A fanfiction could also explore a scenario where Lucy and Juvia enter a magic tournament together as a team. They face various opponents and use their combined skills to win. Their opponents might underestimate them at first because they seem like an unlikely pair. But they prove everyone wrong with their strategic use of magic. Lucy could summon spirits to distract opponents while Juvia attacks with powerful water spells.