I'm not sure specifically as I haven't read this particular fanfiction. However, it might involve a fictional scenario where Natsu and Ultear's relationship takes a turn towards having a family, with all the emotional and story - driven elements that come with it like how they deal with the pregnancy, how it affects their relationships with others in the story's universe.
Perhaps characters like Gray or Erza from Natsu's side could be part of the story. They might initially be shocked but then come around to support their friend. On Ultear's side, any of her former comrades or mentors could show up. They could have different reactions, some might be happy for her while others could see it as a threat to their own plans or to Ultear's future in a more negative way.
Well, perhaps the pregnancy could be part of a prophecy. This would make them targets for both good and bad forces. They'd have to journey to find out more about the prophecy and how their baby fits into it. Along the way, they'd face challenges that test their relationship and their resolve to protect their family.
Well, perhaps in the fanfiction, Natsu and Ultear get married in a grand ceremony attended by all their friends from the guild. After marriage, they decide to go on adventures together. Ultear could use her time - magic to help Natsu in battles, like rewinding time a bit to give him an edge. They also start a family, with Natsu teaching their kids about the importance of friendship and Ultear teaching them magic.
Perhaps in this fanfiction, a magical spell goes wrong and creates a baby that has a connection to both Natsu and Ultear. They then have to deal with the consequences. Natsu might try to use his fire magic to keep the baby warm in a rather clumsy way at first. Ultear, on the other hand, uses her time - related magic to create things for the baby like a cozy crib or toys. They face challenges like getting the baby to sleep through the night and protecting it from any villains who might want to use the baby for their own evil purposes.
Some of their more light - hearted friends, like Happy, might make jokes about Natsu becoming a father. But overall, the Fairy Tail guild would come together to support them. Makarov, as the guild master, would ensure their safety and provide any resources they need. And Levy might be researching about pregnancies in the magical world to give them advice.
In the 'natsu gets cana pregnant fanfiction', perhaps it starts with a magical accident. Natsu and Cana might be exposed to some strange magic that causes an unforeseen bond between them. As a result, Cana discovers she is pregnant. Then, they would have to face the reactions of their friends and the challenges that come with this new situation in their lives.
Well, it could involve a lot of emotional turmoil. Maybe Natsu initially panics but then slowly accepts his new role as a future father. They might face challenges from their friends or guildmates who are surprised by the sudden situation.
Well, a plot could involve Natsu and Lucy trying to keep the pregnancy a secret at first. They don't want to cause a stir in the guild right away. As the pregnancy progresses, they start to realize they need to prepare. Natsu tries to earn extra money by taking on dangerous jobs, which Lucy doesn't like. Meanwhile, the baby could have some sort of special magic that starts to show even before it's born, attracting the wrong kind of attention from dark mages.
In such a fanfiction, perhaps Natsu would become extremely protective of Mira. They could also start to think about how to raise their child in a world full of magic and danger. Maybe they would seek advice from their more experienced friends like Makarov. Natsu might even start working harder to provide for the family, while Mira could focus on taking care of herself during the pregnancy.
The plot could develop with Natsu and the girl initially in shock. Then they might start making plans for the future, like finding a place to live. Natsu could also try to earn more money for the upcoming baby. Their friends would likely get involved, some offering help and others maybe being a bit skeptical.