In a fan - made story, their relationship could develop through shared goals. For example, if there is a threat to the Fairy Tail world that only their combined powers can stop. As they work together towards this goal, they start to understand each other better. Zeref might be softened by Lucy's optimism and determination, and Lucy might see the good in Zeref that is buried deep beneath his dark exterior. This could lead to a relationship filled with mutual respect and love over time.
Their relationship could develop differently if Natsu didn't initially see Zeref as an enemy. Instead of the typical animosity, Natsu could approach Zeref with curiosity. Maybe he wants to understand why Zeref created him and what his purpose really is. This could lead to a more cooperative relationship from the start.
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.
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.
Their relationship could develop through shared adventures. Every time they go on a quest together, they learn more about each other. For instance, during a battle against a powerful enemy, they might have to rely on each other's unique abilities. Lucy's strategic thinking combined with Virgo's brute strength and loyalty can make them an unbeatable team.
It could develop in a rather unexpected way. Suppose there's a magical accident that causes their minds to be linked for a short time. They get to see each other's deepest fears and desires. This experience could make them more empathetic towards each other. After that, Mystogan might be more protective of Wendy, and Wendy could be more understanding of Mystogan's often - mysterious ways. Their relationship could then evolve from a simple acquaintance in the guild to a pair that has a special connection that is unique to them.
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.