In addition to Natsu, Wendy could be a main character in the 'natsu is a dragon god fanfic'. Since she also has dragon - related powers, she could have a special connection with Natsu in this new situation. Maybe she helps him understand more about his dragon god powers. And Makarov, as the guild master of Fairy Tail, would also be a significant character. He would be concerned about how Natsu's new status affects the guild and the magical world as a whole.
In the 'natsu is a dragon god fanfic', a possible plot is that Natsu has to learn how to control his dragon god abilities. He might struggle at first, accidentally causing chaos around him. And there could be a sub - plot where he has to go on a journey to find a special artifact or knowledge that will help him master his powers fully. Also, his love life could be affected. If he has feelings for someone, his new powers could either strengthen their relationship or create some misunderstandings.
Well, in 'natsu is a dragon god slayer fanfic', themes like growth and evolution are very common. Natsu's character is growing not just in terms of power but also in his understanding of the world around him. Family is also a theme that pops up. Since dragons are like family to him in a way, his connection to them and how it affects his actions is explored. And of course, the theme of heroism. Natsu is seen as a hero, especially with his new powers as a dragon god slayer, and how he lives up to that role, facing challenges and saving the day, is a big part of these fanfics.
Gray might show up too. He could start as a bit of a rival, not believing that Natsu can really achieve great things with this Dragon God training. But as the story progresses, he could become more of a supporter. And then there's Lucy. She might be worried about Natsu during the training, and also use her celestial spirit magic to help Natsu in some unexpected ways during his training, like summoning spirits that can provide unique challenges for Natsu to overcome.
Happy, Natsu's flying cat companion, would definitely be a main character. He would be there to provide comic relief as always, but also be a source of emotional support for Natsu during his transformation into a dragon god. Erza might also be a prominent character. With her strong leadership skills and powerful magic, she could be guiding the guild during the times when Natsu is still coming to terms with his powers and the changes it brings to the guild.
I highly doubt it's a popular fanfic given the rather inappropriate and unclear title. Most popular fanfics usually have more engaging and appropriate titles that give a better sense of the story.
One popular 'natsu is a dragon god slayer fanfic' might be 'Natsu's Ascent'. In this fic, Natsu's journey as a dragon god slayer is filled with intense battles and character growth. Another could be 'The Dragon God Slayer's Legacy' which delves into how Natsu's new powers affect his relationships with his guildmates. There's also 'Natsu: Dragon God Slayer Reborn' that takes a different turn on his origin story as a dragon god slayer.
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.
I'm not sure specifically as it could vary greatly. It might be a fanfic about Natsu from 'Fairy Tail' who is a different kind of dragon, perhaps with unique powers or a different origin story compared to the original.