Well, it could be that the fever is a symptom of a more mysterious illness in the fanfiction world. For example, it could be related to a magical curse or some new virus in a science - fiction setting. Then the story would revolve around finding the cure for this strange fever.
Maybe it could be about how her friends take care of her. They might bring her medicine, make her soup, and stay by her side to comfort her while she's dealing with the fever.
There could be her family members. Her mother might be the one constantly checking on her temperature and making sure she is comfortable.
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 Lucy discovers an ancient artifact that gives her new powers. For example, she could find a magic amulet that allows her to control the elements. Then she has to learn how to use these powers to save her town from a mysterious threat.
One common plot twist could be that the person she trusts most, like her best friend, betrays her for power. Maybe her friend is offered a high - ranking position in a magical guild or something and has to sacrifice Lucy to get it. Another could be that a love interest betrays her. He might be secretly working for an enemy and using Lucy to get information about her family or her magic.
Well, a plot could involve Natsu and Lucy trying to keep the pregnancy a secret at first. They don't want to cause a stir in the guild right away. As the pregnancy progresses, they start to realize they need to prepare. Natsu tries to earn extra money by taking on dangerous jobs, which Lucy doesn't like. Meanwhile, the baby could have some sort of special magic that starts to show even before it's born, attracting the wrong kind of attention from dark mages.
In the 'ichigo gets a fever fanfiction', it could start with Ichigo suddenly feeling unwell and getting a high fever. His family might be in a panic. His father, being a doctor, would first examine him. Meanwhile, his friends from the Soul Society could sense his weakened state through their spiritual connection and try to find a way to help him. This could lead to a series of events where they have to face challenges both in the human world and the Soul Society to get the right remedy for Ichigo.
Lucy could face isolation. People in the fanfiction world might avoid her, and she could be left all alone. This could also lead to her losing confidence in herself as she is constantly being blamed for something she didn't do.
I think his family would be the first to help. His sisters could bring him cold compresses to reduce the fever, and his father would use his medical skills. And from the Soul Society, Renji might come to check on him, as he and Ichigo have a sort of friendly rivalry. He would want to make sure Ichigo gets better soon so they can have their next sparring match.
One possible plot could be that Natsu is completely devastated by Lucy's death. He turns to alcohol as a way to numb the pain. His friends might try to reach out to him, but he pushes them away in his grief. He could start having flashbacks of their adventures together while drunk, which makes his pain even more intense.
Well, one possible plot could be that Natsu and Lucy's relationship evolves from friendship to something more romantic. Then, an unexpected pregnancy occurs which throws their lives into chaos. They might have to face the reactions of their friends and deal with their own fears and insecurities about becoming parents.