Well, it could be really exciting. Their daughter might inherit Lucy's celestial magic and Natsu's dragon slayer powers. Maybe she'd be on adventures with the new generation of Fairy Tail wizards, facing powerful enemies and making new friends just like her parents did.
In a fanfiction about their daughter, she could have a unique personality. Since Lucy is intelligent and kind, and Natsu is brave and hot - tempered, their daughter might be a combination of these traits. She could use her magic in innovative ways, for example, combining celestial and dragon slayer magic to create new spells. And she would surely have some great storylines involving the other members of Fairy Tail, old and new.
She would fit in very well. The Fairy Tail guild is all about family and acceptance. Given her parents are Lucy and Natsu, she'd be welcomed with open arms. She could learn from the older members like Makarov and Mirajane, and bond with the younger ones like Romeo. Her magic skills would also contribute to the guild's strength during battles or when helping the town.
One possibility is that their daughter has a special ability to combine Natsu's fire magic and Lucy's summoning magic in unexpected ways. For example, she could summon a fire - based celestial spirit. She might grow up in a Fairy Tail that has changed a bit since her parents' time, with new members and new challenges. She could be mentored by some of the older guild members like Erza or Gray. And as she comes of age, she might discover secrets about her family's past that put her in a position to make important decisions for the future of the guild and the magical world at large.
A possible scenario in a fanfiction could be that Natsu realizes his true feelings for Lucy during a mission where he sees her in danger. He rushes to save her and in the heat of the moment, their lips meet. This kind of kiss is often a spontaneous expression of love and care in fanfiction stories.
The child might have Natsu's pink hair, but with Lucy's brown eyes. Or perhaps a combination of their features, like pinkish - brown hair.
He could kidnap her because he believes she's in immediate danger. Natsu is very impulsive and might not have time to explain things properly, so he just takes her away to keep her safe.
In some fanfictions, if Natsu kidnapped Lucy, it could be a comical situation. Natsu might do it out of his own strange sense of protecting Lucy in an overzealous way. Maybe he thinks there's a danger that only he can keep her safe from, and his impulsive nature leads him to this 'kidnapping' which is more like a forced protection.
In many fanfictions, Natsu and Lucy's first kiss is often a very emotional and anticipated moment. Some writers might describe it as a spontaneous act during a dangerous adventure, like when they think they might not survive. Natsu, being his impulsive self, might suddenly realize his deep feelings for Lucy and plant a kiss on her lips.
Yes, there are many appropriate fanfictions about Natsu and Lucy's relationship. For example, some focus on their adventures together as friends and comrades in the Fairy Tail guild. They might go on quests, face powerful enemies side by side, and in the process, their friendship deepens. These fanfictions often explore their loyalty to each other and how they support one another in difficult times.
She might also have the ability to summon celestial spirits like Lucy. But instead of just summoning them in the normal way, she could use her fire magic to enhance their powers. For example, if she summons a spirit of a warrior, she could make the warrior's weapon engulfed in flames. She could also have a unique bond with a particular spirit that was passed down from Lucy, and this spirit could teach her special magic or give her advice on how to handle difficult situations.
In the fanfiction, their relationship might have developed over many adventures. They could have realized their love for each other during a particularly dangerous mission. Natsu, always protective of Lucy, and Lucy, always believing in Natsu. Their marriage would symbolize the deep bond they share. It might also be a way to bring the guild closer together, as everyone is so happy for them. And perhaps, in this fanfiction, they would start a new chapter in their lives, thinking about having a family in the future.