Obviously, Natsu himself would be one of the main characters. His parents, whose identities are likely to be revealed in the fanfiction. There could also be his friends, like Lucy, Gray and Erza. They might be there to support Natsu during this emotional encounter or play a role in helping him find his parents.
In the 'natsu meets his parents fanfiction', Natsu may initially be in shock when he meets them. His parents could look exactly like him or have some unique features. They might take him on a journey to a place that was important to their family. Along the way, Natsu could learn valuable lessons about family, love and self - discovery.
Perhaps a theme of self - discovery. Through the difficult situation of being abused by his parents, Natsu might start to learn more about himself, his boundaries, and what he truly wants in life. He could realize his own worth despite his parents' actions.
It should avoid glorifying the abuse. Instead, it can focus on Natsu's journey to overcome it. Also, it can provide resources or mentions of help that abuse victims can seek in real life.
I'm not sure who exactly Natsu is just from 'natsu reads fanfiction'. It could be a normal person who just enjoys reading fan - made stories. Maybe it's a nickname for someone within a particular fan community.
The OC could have accidentally said or done something that made Natsu feel unwanted or unappreciated in Fairy Tail. For example, if the OC is a new member and got more attention than Natsu in a certain situation, it might have bruised his ego and led to his decision to leave.
In some fanfictions, Acnologia is made out to be Natsu's father. But this is not part of the original canon of the Fairy Tail series. Fanfiction writers often like to create such unexpected family relationships to add new twists to the story.
He might be more in tune with nature. Since dragons are often associated with nature, Natsu could have a deeper respect and understanding of the natural world around him, showing more kindness to animals and plants.
In addition to Lucy and Erza, there could be other female characters from the series. Maybe some minor characters who have always admired Natsu from afar. For example, that one girl from the guild who always blushes when Natsu is around. Another possibility is a powerful female dragon who sees Natsu's transformation into a Dragon God as a sign of his worthiness. She might join his harem, bringing a different kind of relationship dynamic as she has her own dragon - like qualities and power. And there could be a female mage from a different guild who hears about Natsu's new status and is intrigued, eventually becoming part of his harem.