There could be new characters introduced, like a wandering mage who also has a troubled past. This mage could understand Natsu's feelings of abandonment and they could become friends. Also, a character from a different guild that has always admired Natsu from afar might reach out to him.
Lucy might still be on Natsu's side even after his abandonment. She could be his closest friend during this time. Additionally, Happy could play a crucial role in introducing Natsu to some of the small, friendly magical creatures in the area. These creatures, with their simple ways, could be a source of comfort and new friendship for Natsu.
Well, they could have an interaction where Natsu accidentally sets off Juvia's temper. Maybe Natsu accidentally melts some of Juvia's precious water - made items. Juvia gets mad, but Natsu's cluelessness about how much he's upset her is kind of endearing. Eventually, Juvia forgives him when she sees how he was just being his usual, careless self.
There could be a mysterious old wizard who takes Natsu under his wing when he leaves Fairy Tail. This wizard might have knowledge of ancient magics that Natsu is eager to learn.
In fanfiction, Natsu's age can vary greatly. Some authors might keep him at his canonical age from the original Fairy Tail series, which is around 17 - 18 years old at the start. However, in alternate universe fanfictions, he could be older or younger depending on the plot. For example, in a time - travel based fanfic, he could be much older if the story takes place far into the future or much younger if it goes back to his childhood days.
Yes, in a lot of Fairy Tail fanfiction, Natsu can be overpowered. Writers often like to amp up his powers for more exciting storylines. For example, they might give him new fire - based abilities or make his existing ones even stronger to defeat more powerful foes.
Maybe an old acquaintance from Natsu's past that we haven't seen much in the original Fairy Tail story. This person could be a powerful but reclusive mage who decides to help Natsu out of respect for his father or some past debt. They could offer Natsu shelter and train him in new forms of magic to help him face the challenges during his exile.
He could have the power to control different types of fire, not just the regular one. For example, blue - flame fire that is much hotter and more destructive.
One possible scenario could be that the new kid is a huge fan of Natsu and joins Fairy Tail School Academy hoping to meet him. The new kid might be really nervous at first, but then Natsu's warm and friendly personality makes him feel welcome. Natsu could show the new kid around the school, introducing him to all the cool magical things there.
Natsu could get really angry at Lucy. He has a bit of a temper, and being tied up against his will might make him lash out at her once he gets free. Another consequence could be that the other guild members might find out and either laugh about it or scold Lucy for her actions. It could also lead to some sort of competition between them, like Natsu trying to prove he can't be tied up so easily next time.
In this fanfiction, Natsu could discover that his abandonment was part of a bigger plan within Fairy Tail to protect him from a greater threat. He might initially be angry and resentful, but as he uncovers the truth, he has to decide whether to forgive his old guild or not. He could also meet other characters who were also once abandoned and form a bond with them to face the challenges together.
In fanfictions like this, the character development of Natsu within the context of Sabertooth is interesting. He could learn new magic techniques from them or teach them his own unique brand of Fairy Tail spirit. It might also explore how the different cultures of the two guilds clash or blend.