In this kind of fanfiction, they might face various challenges. Maybe they'll have to find their way back on their own. They could encounter dangerous magical creatures and have to rely on their own skills and the bond between them to survive.
The main characters are clearly Natsu and Lisanna. Natsu is a well - known character with his fiery personality and powerful dragon - slayer magic. Lisanna is also important, she has her own set of skills and a unique relationship with Natsu.
Their relationship with the guild leaders could become strained. The leaders might see them as irresponsible for getting left back. However, as time passes, Lisanna and Natsu could prove themselves in other ways, like taking on extra tasks around the guild to show their dedication. This could gradually change the leaders' perception of them and strengthen their relationship in the long run.
In this fanfiction, they might have to face a series of challenges alone. Maybe they'll encounter powerful enemies that they have to defeat without the help of their usual comrades. They could also discover new powers or abilities within themselves during this time of being left behind.
It's Natsu and Erza. Natsu, the energetic dragon slayer, is always ready for a fight and has a great sense of loyalty towards his friends. Erza, with her strict yet caring nature, is a force to be reckoned with. In this fanfiction, their individual skills and personalities will likely be explored more deeply as they are left behind.
Perhaps they get left back because of some external factors. Say, an enemy attacked their guild right before an important exam. Lisanna and Natsu were so busy fighting off the enemy and protecting their guildmates that they missed out on crucial study time. They might have also gotten injured during the battle, which further hindered their performance in the assessment, causing them to be held back.
Well, it could be about Natsu being accidentally or deliberately left in a certain place. Maybe his friends go on a mission without him, and he has to find his own way back or prove himself while being left behind. It might also involve his feelings of abandonment and how he overcomes them.
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.
Love is a very common theme. Since they have a pre - existing relationship in the original story, fanfictions often expand on their romantic feelings for each other. Another common theme is friendship. Their friendship is the foundation of their relationship, and many fanfictions explore how their friendship evolves into something more.
Lisanna might face a lot of backlash from the guild. Her friends could be disappointed in her and might not trust her as much. She could lose her standing in the guild and have to work hard to regain people's respect.