Well, it could start with Lucy being in a situation where she witnesses the destruction caused by a celestial dragon. This event stirs something deep within her, and she decides she wants to be able to protect everyone from such a threat. So, she embarks on a journey to become a celestial dragon slayer. She may travel to different realms or seek out rare magical items that can enhance her abilities. As she progresses, she could form alliances with other powerful mages who share her goal or have knowledge about celestial dragons. And gradually, she builds her skills and reputation as a celestial dragon slayer.
Perhaps an ancient sorcerer who has the ability to control celestial dragons. He sees Lucy as an obstacle to his domination over the world using the power of these dragons. He would use his vast knowledge of magic and his control over the dragons to try and defeat her.
One possibility is that Lucy discovers a hidden power within herself that is related to dragon slaying. Maybe she has a long - lost ancestor who was a dragon slayer. This newfound power could lead her on a journey to learn more about it, facing challenges along the way, like dealing with other mages who are jealous or scared of her new abilities.
One interesting aspect could be how she trains to become a Celestial Dragon Slayer. Maybe she discovers an ancient magic that combines the two, and she has to learn to control the newfound power. This could lead to some great character development as she struggles with the increased power and the responsibility that comes with it.
In a 'Fairy Tail Lucy becomes a Dragon Slayer' fanfic, it could start with Lucy being in a life - threatening situation. To survive, she unknowingly absorbs the power of a dying dragon. This power starts to change her. At first, she is scared of the changes. But then, with the support of her friends, she decides to embrace it. She then begins a journey to master her new powers. She might learn that her Dragon Slayer magic is linked to a special type of celestial spirit that has dragon - like qualities, and she has to find and bond with this spirit to fully control her powers.
It could be about Lucy having an adventure in the world where celestial dragons exist. Maybe she befriends one or tries to change their cruel ways.
She could have the ability to breathe celestial - themed 'dragon breath'. For instance, it might be a blast of star - like energy that can pierce through dark magic. Her celestial spirits might also gain new forms or abilities. For example, Aquarius could become a more combat - ready mermaid with dragon - like fins that can slice through water and enemies.
In these fanfictions, a major theme is the combination of different magics. Lucy has her celestial spirit magic and now as a dragon slayer, how these two magics interact and complement each other. Another theme is the search for identity. She is no longer just Lucy the celestial wizard but also a dragon slayer, and she has to figure out what that means for her place in the world and among her friends.
Well, a plot could revolve around Lucy being the only one who can stop an ancient Celestial Dragon that has been awakened from its slumber and is causing chaos. As a Celestial Dragon Slayer, she has to figure out how to communicate with the dragon first and then find a way to either calm it or defeat it. This could lead to her delving deeper into the lore of Celestial Dragons and her own family's connection to them.
In the 'lucy becomes a celestial spirit fanfic', perhaps Lucy discovers a hidden power within herself that has a connection to the celestial spirits. As she tries to understand this power, she gradually takes on the characteristics of a celestial spirit. She could start having the ability to communicate with them on a deeper level and even access their powers in a unique way.
Well, obviously Lucy is one of the main characters since it's in the title. She's likely to be the central figure around which the story revolves. There might also be other dragon slayers who could be important characters. They could be friends or rivals to Lucy, and their interactions with her would shape the story.