In some fanfictions, their relationship develops through shared battles. As they fight side by side against enemies, they start to trust each other more and more, which deepens their connection.
Often, in fanfiction, their relationship might develop when Lucy is in trouble and Leo comes to her rescue. This heroic act makes Lucy see Leo in a new light, and they begin to grow closer. For example, if Lucy is captured by a group of bandits, Leo could use his celestial magic to break her free and in the process, they realize their feelings for each other are stronger than they thought.
Their relationship could develop through shared experiences. For instance, if they both get caught in a magical trap that only they can escape from by working together. They would have to rely on each other's skills, and this could lead to a newfound respect. Jackal might see Lucy's intelligence in figuring out the magic of the trap, and Lucy could see Jackal's tenacity.
In a fanfiction, their relationship might develop because of a mutual friend. Maybe a character from Fairy Tail is in danger and they both care about that person. So they work together to rescue the friend. During this rescue mission, they see different sides of each other. Angel might see Lucy's determination and kindness, and Lucy might see Angel's hidden strengths and softer side. This new understanding can lead to a closer relationship between them.
In a fanfiction, their relationship might develop if they start to open up more about their pasts. Lucy could share more about her family and how she came to be a celestial wizard. Natsu could talk about his search for Igneel. By sharing these deep parts of themselves, they would build a stronger emotional connection. Also, small moments like Natsu saving Lucy from a small danger, like a falling object in the guild hall, can add up and gradually develop their relationship.
To develop their relationship, start with small interactions. Have the OC offer to help Lucy with her celestial spirit summoning, like finding a rare ingredient for a spirit - summoning spell. Then, they could have some shared experiences, such as getting trapped in a cave during a mission. This forces them to rely on each other, talk, and get to know one another better. Another way is to give them common goals. For example, they both want to defeat a certain dark mage who has been causing trouble in the area. Working towards this goal together will bring them closer.
One way their relationship could develop is through a mutual understanding of their powers. If they start training together to combine their celestial magic in new ways, they'll have to communicate and rely on each other more. This would not only strengthen their magical bond but also their personal relationship. Another aspect could be that they face a situation where they have to make sacrifices for each other. Say, Lucy has to give up a chance at a powerful magical item to save Loke, or Loke has to put himself in great danger to protect Lucy's family. These kinds of selfless acts would take their relationship to a new level.
Their relationship could start with mutual suspicion. Lucy is a member of Fairy Tail, and Midnight is from a different, often opposing group. But as they interact more, they might find common interests. For instance, they could both be interested in a particular type of magic theory. This shared interest could be the starting point of them gradually warming up to each other.
Often, in fanfiction, a common plot is that Juvia and Lucy are paired up for a task. This forced proximity makes them learn about each other. Lucy might introduce Juvia to new ways of using magic in a more creative way, while Juvia shows Lucy how to be more in tune with her emotions. As they face difficulties together during the task, they build a bond of trust. This trust then evolves into a deep friendship where they are always there for each other, whether it's cheering each other on during a magic competition or comforting each other after a loss.
Their relationship could develop through shared secrets. For example, they might discover something about the guild's past that they decide to keep between themselves. This would create a special bond.
Their relationship could start as a simple acquaintance when they are assigned to the same mission. Then, as they face difficulties together, they gradually become friends. For example, Dan might save Lucy from a dangerous attack, and Lucy in turn helps Dan understand the workings of the Fairy Tail guild better.
In a fanfic, their relationship could develop romantically. They might start by sharing small moments together, like watching the sunset after a mission. As they continue to interact, they find that they have a lot in common despite their differences. Aries' gentle nature softens Leo's more brash side, and Leo's passion makes Aries feel more alive. Their relationship could be a slow - burn one, with lots of tender moments and a few obstacles along the way, such as other characters being jealous or disapproving, but in the end, they could end up together.