Natsu's friends like Gray, Erza, and Lucy are often involved. Gray might be constantly teasing Natsu about the transformation, creating some funny banter between them. Erza could be the one who tries to keep order and protect Natsu in this new form. Lucy might offer more emotional support, sharing girl - related experiences with Natsu to help her adjust.
There could be villains as well. For example, if the transformation was caused by a villain's spell, that villain would be part of the story. The villain might be trying to use Natsu's new form for some evil plan, like using her to infiltrate the guild or cause chaos among Natsu's friends. And of course, the guild master might also be involved, having to deal with the situation and ensure Natsu's well - being.
Gray is another character. His ice - magic can complement Natsu's fire - magic. They might team up to fight enemies or overcome obstacles in the way of saving Fairy Tail. Sometimes they bicker while doing so, which adds some humor to the story.
Perhaps characters like Gray or Erza from Natsu's side could be part of the story. They might initially be shocked but then come around to support their friend. On Ultear's side, any of her former comrades or mentors could show up. They could have different reactions, some might be happy for her while others could see it as a threat to their own plans or to Ultear's future in a more negative way.
Lucy could also play a major role. She might be the one to help Natsu adjust to his new life as a girl. Maybe she gives Natsu tips on how to dress and act like a girl, and they could have deeper conversations about what it means to be a girl in their magical 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.
Lucy could be a main character. Since she's often by Natsu's side, she would likely be deeply involved in his recovery. She could use her celestial spirit magic to try and protect him while he's injured or search for a way to heal him.
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.
One interesting plotline could be Natsu trying to adjust to the new physical form while still having the same adventurous spirit. For example, Natsu might initially struggle with wearing different types of clothes that are more suitable for a female body. Another plotline could be how Natsu's friends react. Some friends might be shocked at first, but then quickly accept and help Natsu through this strange transformation. There could also be a plotline where Natsu discovers new abilities or sensitivities that come with being in a female form.
There could be some new dragon characters created specifically for this fanfiction. These dragons might have unique abilities and characteristics that are different from the known dragons in the original Fairy Tail series. And perhaps there are some wise old wizards or spirits in the fanfiction who guide Natsu in between his dragon - training sessions.
There could be a female dragon named Ignis who is very fiery and passionate, always trying to be the closest to Natsu. Another could be a more gentle dragon named Aqua, who has water - based powers and uses her calm nature to balance out the more intense dragons in the harem.
One of the main characters could be Happy, Natsu's loyal flying cat companion. Happy would likely be by Natsu's side during his retirement, still providing his comical relief and support. Another character could be Lucy. She might be concerned about Natsu's retirement decision and try to understand his reasons, or she could also be retiring from her own magical adventures and join Natsu in his new peaceful life.