Well, perhaps Natsu could be sparring with Lucy and accidentally land a more powerful blow than he intended during a training session. Maybe he's in his dragon force mode and loses control for a second, hitting Lucy hard enough to make her fall and get injured.
One scenario could be that Natsu and Lucy are on a mission together. Natsu is trying to protect Lucy from a magic attack, but his counter - attack goes awry. His fire magic might ricochet off the enemy's shield and hit Lucy instead. This would create a tense situation where Natsu has to deal with his mistake, Lucy has to deal with her injury, and they both have to figure out how to continue the mission while also mending their relationship after such an accident.
In the fanfiction, it could be that Natsu is in a hurry to get to an enemy and doesn't notice Lucy in his path. He runs into her or knocks her over in his haste, causing her to get hurt. This would lead to a lot of guilt on Natsu's part and he'd probably try his best to make it up to her. He might bring her her favorite food or stay by her bedside while she recovers.
Natsu would likely be extremely guilty. He might immediately stop whatever he was doing and rush to Lucy's side.
Perhaps Natsu kidnaps Lucy as a prank that goes wrong. He initially thinks it'll be a funny joke, like taking her away during a guild party just for a bit of chaos. But then things get out of hand. Lucy might be really angry at first, but as they are alone together, they start to have some deep conversations and understand each other better.
A possible plot could be that their married life is disrupted by a mysterious force that is causing chaos in the magical world. Natsu and Lucy, being the strong couple they are, set out to find the source of this problem. As they journey, they discover secrets about their own powers and how their union might be the key to saving the world. There could be moments of doubt and fear, but their love for each other always pulls them through.
Well, one possible plot development could be that Natsu is initially hesitant. After all, he and Lucy have a complex relationship that's more of a deep friendship with some unspoken feelings. But Asuka's words make him start to see Lucy in a new light. He might start to notice little things about her that he hadn't paid much attention to before, like the way her eyes sparkle when she's excited or how she always has a kind word for everyone. This could lead to a series of awkward but sweet moments between them as Natsu tries to figure out his feelings.
Well, one possible plot could be that Lucy has to face the challenges of pregnancy alone after Natsu leaves. She might struggle with financial difficulties and the emotional turmoil of raising a child without the father. She could then find support in her friends in the guild, who help her through the tough times and she eventually becomes a strong, independent mother.
Well, one possible plot could be that after many adventures together, Natsu finally realizes his deep love for Lucy. He might plan a big, romantic proposal during one of their guild parties. Then the wedding could be a grand affair with all their Fairy Tail friends in attendance. They could exchange heartfelt vows, and the whole guild could celebrate their union with lots of food, music and magic.
Well, perhaps in this fanfiction, Natsu calling Lucy 'baby' is a sign of a new level of closeness in their relationship. It could start with Natsu protecting Lucy in a dangerous situation and instinctively calling her 'baby' as he holds her close. This then leads to Lucy being a bit flustered at first but gradually getting used to it and even liking it, and it becomes a special part of their bond.
One possible plot is that in this fanfic world, female Natsu has a special power that only male Lucy can help her control. So they embark on a journey together. Along the way, they face various challenges like battling powerful demons. Their relationship starts as comrades but gradually develops into a deeper bond as they understand each other more.
Maybe the story could start with Natsu and Lucy going on a special mission. During this mission, they face a great danger that makes them realize how much they mean to each other. Once they return, Natsu decides it's time to get married. The fanfiction could then focus on the wedding preparations, like Lucy choosing her dress and Natsu trying to find the perfect gift for her.
Perhaps the story delves into how they handle disagreements as a married couple. Since Natsu can be impulsive and Lucy is more level - headed at times, they might have to work through their differences. It could also show how their love for each other deepens through these experiences.