Power and responsibility is a common theme. As Natsu becomes a dragon god slayer, he has more power, but also more duties. Another theme is friendship. His friends in Fairy Tail still support him even as he changes. And there's often the theme of self - improvement, as Natsu has to master his new abilities.
One idea could be Natsu discovering new and more powerful fire-based spells as a Fire God Slayer. Maybe he has to face a powerful ice - based enemy that forces him to tap into deeper levels of his god - slayer magic. This would make for an exciting action - filled fanfiction.
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.
One great 'Fairy Tail Natsu Dragon God Slayer' fanfiction is 'The Dragon's Ascent'. It really delves into Natsu's growth as a Dragon God Slayer in a unique way. The author creates new challenges for Natsu that are both exciting and in - line with the Fairy Tail universe.
One possible plot could be that Natsu discovers his new power as a war god slayer magic user. He then has to face a series of powerful enemies who are threatening the world. Along the way, he might meet new allies who also have unique magic abilities. As he battles these foes, he gradually masters his war god slayer magic and becomes a more powerful wizard.
Another aspect is the world - building. Since it's set in the Fairy Tail universe, the fanfiction should expand on the existing lore. Maybe introduce new dragons or aspects of the Dragon God Slayer magic that we haven't seen in the original series. This makes the fanfiction feel like a natural extension of the Fairy Tail world.
I've also heard of a fanfiction titled 'The New Era of Natsu, the Dragon God Slayer'. This fanfic focuses on Natsu's journey after becoming a dragon god slayer. It has a lot of elements of self - discovery. Natsu has to learn how to control his new powers and face enemies that are far more dangerous than before. The author does a great job of creating a vivid world around Natsu's new identity.
It could be another powerful mage who is jealous of Natsu's new war god slayer magic and wants to steal it for himself. This mage might have been researching ways to gain such powerful magic for a long time and sees Natsu as an obstacle to his own plans.
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.
A good plot twist could be that Natsu's Fire God Slayer magic is actually a curse in disguise. It was given to him by an evil entity that wants to use him for its own purposes. This would completely change the direction of the story and add a lot of mystery.