It could also develop if they have a common goal. Let's say they both want to find a rare magical item. Along the journey, they would face many obstacles. Jackal's brute force and Lucy's strategic thinking would complement each other. They might start as reluctant partners but end up as friends or even something more as they realize how well they work together towards this goal. This would be a gradual development of their relationship with many ups and downs along the way.
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.
One idea could be that Jackal, after some soul - searching, decides to turn over a new leaf and teams up with Lucy. They could go on a mission to retrieve a powerful magical artifact that was once used by an ancient dark wizard. Along the way, Jackal's knowledge of the dark arts helps them navigate through various traps, while Lucy's celestial magic provides the offensive and defensive power they need.
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.
Their relationship could start off as adversarial. Lucy would be distrustful of Jackal due to his past actions. However, as they are forced to work together on a mission, they start to see each other in a new light. For example, Jackal might save Lucy from a dangerous spell, and Lucy might use her magic to heal Jackal when he is injured. This mutual dependence could lead to a grudging respect and then friendship.
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.
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.
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 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.
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, 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.