The Magic Council could be potential enemies. Since Natsu is an outlaw, they would be the ones to try and capture him. Also, dark guilds might see him as a threat or a valuable asset to capture. They could send their strongest members after him.
One group of potential enemies would be bounty hunters. They would be after Natsu for the reward on his head. Another could be the remnants of Zeref's followers. If they think Natsu's new outlaw status can be exploited for their own dark purposes, they would target him. Additionally, some of the more traditional and strict magical families might see Natsu as a bad influence and try to eliminate him.
One common theme could be redemption. Natsu, being an outlaw, might be on a journey to redeem himself for past misdeeds. Another could be power struggles, as he is a dragon slayer and there might be others vying for power or trying to control him. Also, friendship might be a theme, as he could be making new allies even in his outlaw status.
Popularity of 'dragon slayer is outlaw fanfiction' is hard to gauge. It could be popular among those who are interested in subverting traditional dragon - related tropes. However, compared to more common fanfiction themes like romance - centered ones in well - known fictional universes, it might not have as wide an audience. It also depends on how visible it is. If it's been promoted well on platforms like Archive of Our Own or FanFiction.net, and if it has received positive reviews and word - of - mouth recommendations, it could be quite popular within a certain group of fans.
A young dragon slayer - in - training who idolizes Natsu. This character could be from a far - off land and has heard tales of Natsu's dual powers. They could have their own unique magic related to a different element that complements Natsu's powers.
There could be a young mage who idolizes Natsu and joins him on his adventures. This character could be inexperienced but full of enthusiasm, providing some comical moments as well as opportunities for Natsu to be a mentor.
I'm not sure specifically as I haven't read this particular fanfiction. But generally, it might be about a dragon slayer who is an outlaw. Maybe the slayer has broken some laws or rules in the fictional world they are in, perhaps in relation to how dragon slaying is regulated or for some other misdeeds. It could also explore the character's journey as an outlaw while having the unique ability to slay dragons.
In the 'king of dragon slayer fanfiction', Natsu is likely a central figure. He might have special powers related to slaying dragons, like breathing fire or having enhanced strength. His character could be developed in ways that are different from the original series, perhaps with new relationships and challenges within the fanfiction world.
Potentially, we could see some celestial dragon characters. They might be ancient and powerful beings. Some could be friendly towards Natsu, seeing him as a new hope for their kind. Others might be more hostile, seeing him as an intruder or a threat to their traditional ways. There could also be other mages from different guilds who are either curious or envious of Natsu's situation with the celestial dragons.
Another potential character could be a dragon oracle. This oracle could have the ability to see Natsu's true nature and destiny. They could either help Natsu understand his powers and purpose or be a bit of a trickster, making Natsu's journey to discover himself even more difficult. And of course, the other members of Fairy Tail would be there to support or sometimes misunderstand Natsu as he deals with his dragon - born identity.
In some fanfictions, there might be original characters created by the author. For instance, a mysterious figure who has some connection to Natsu's multi - dragon slayer abilities. This character could be an antagonist, testing Natsu's skills, or a mentor, guiding him to master his powers better.
It could be a powerful dark wizard who sees Natsu as a threat because of his alpha status among dragon slayers. This wizard might want to eliminate Natsu to gain control over the dragon slayers or to carry out some evil plan without interference.