Who could be the main characters in 'dragon's fire fanfiction'?

A dragon tamer could be the main character. They have a special bond with the dragon and use the dragon's roar to their advantage in battles or to solve problems.

It could be a dark ninja who wants to control the power of the fire dragon for his own evil purposes. He might try to steal the dragon's chakra or use it to destroy villages.

A powerful dark mage who wants to use Lucy's newfound dragon slayer powers for his own evil purposes. He might try to control her or steal her powers.

Perhaps an evil mage who has been researching on how to control dragons. When he hears about Natsu's transformation, he sees Natsu as a perfect specimen to experiment on. So he becomes the main antagonist, trying to capture Natsu and use his powers for his own dark purposes.

It could be an evil dragon slayer who is jealous of Natsu's new form. This antagonist might try to steal Natsu's power or find a way to turn him back to his normal self out of envy.

Well, typically the main character would be a fire dragon slayer. They are the ones with the special connection to the fire dragon powers.

I don't know for sure, but it could be a dragon as one of the main characters, considering the title. Maybe there's also a brave knight or a wizard who has to deal with the dragon.

A determined young trainer could be the main character. They have a special bond with Pokémon and are drawn to the mystery of the Sacred Fire. Their goal could be to learn more about it and protect it if necessary.

A powerful dark dragon slayer who has mastered both shadow and ice magic could be a great antagonist. He could be jealous of Natsu's natural ability with fire and his popularity among the guild, and thus wants to prove his superiority.

Obviously, Gabby would be one of the main characters. Her partner, whether it's Casey or someone else in the series, would also be a major character. The other firefighters at the firehouse like Boden, Herrmann, and Mouch could play important roles as well. They could be the ones offering support, advice, or just being there for Gabby during her pregnancy.