A possible plot twist is that they survive but are transported back in time on Tenrou Island. They have to relive certain events, but this time with the knowledge they already have. This could lead to them changing the past in unexpected ways, like preventing some of the tragedies that originally occurred on the island, which would then have a huge impact on the future of the Fairy Tail guild.
Well, it could be about Natsu being left behind in Tenrou. Maybe it's a story where his friends accidentally leave him there during some sort of event or mission. It might explore his feelings of isolation and how he tries to find his way back to them.
One idea could be exploring how their guild mates react to the news. Some might be overjoyed and offer all kinds of support, while others could be a bit shocked at first. Another could be focusing on how Natsu and Erza themselves adjust to the idea of becoming parents. Natsu might be a bit clumsy at first but full of enthusiasm, and Erza could be more practical and start planning everything right away.
Well, they might become even closer to the other guild members. After surviving such a harrowing experience, the other members could look at Natsu and Erza with newfound respect. Natsu might be seen as even more of a hero, and Erza as an even stronger protector. This could lead to stronger bonds within the guild, with the other members relying on them more in tough situations.
One interesting plot twist could be that when Natsu turns into a dragon, he loses his memory of his human friends. This would create a lot of drama as his friends try to bring back the Natsu they know. Another could be that he turns into a different kind of dragon than expected, perhaps one with a very rare and powerful ability that attracts the wrong kind of attention from dark forces in the fanfiction world. And also, he might transform into a dragon at a crucial moment during a battle, not only surprising his enemies but also his allies, changing the whole dynamic of the fight.
One idea could be a story where Natsu and Erza Knightwalker are on a mission together in a strange land. They face numerous challenges that force them to rely on each other more and more, leading to a deepening of their relationship. Their different personalities, Natsu's impulsiveness and Erza Knightwalker's more stoic nature, could create some really engaging character dynamics.
One common plotline could be how they handle their daily lives together while still being part of their guild. Maybe they have to balance their relationship with their duties as mages.
One possible plot could be that they discover the pregnancy and then face challenges together. Maybe they have to deal with the reactions of their friends in the guild, some being happy and supportive while others might be worried about how it will affect their adventuring lives.
Perhaps in the fanfiction, Natsu meets Erza in a completely new setting, like a parallel universe where the Fairy Tail guild doesn't exist yet. They start off as strangers but quickly realize they have similar goals. Erza might initially be a bit distrustful of Natsu's wild ways, but as they face challenges together, such as a group of bandits attacking a village, they learn to trust and rely on each other.
One possible plot is that a time - travel or alternate - reality situation occurs where Natsu and Erza are already married and have a baby. The story could show how they adjust to this new family life. Natsu might be the fun - loving dad who plays with the baby using his fire powers in a safe way, while Erza is the strict but loving mom who makes sure the baby is well - behaved and learns proper values. They would also have to deal with the reactions of their friends in the guild, some of whom might be shocked or overly excited about the new addition to their family.
Well, perhaps Erza was tricked into believing something false about Natsu. Maybe she was misled by some enemy who made it seem like Natsu was going to endanger the guild. So, in her sense of duty to protect the guild, she took actions that Natsu perceived as betrayal.