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.
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.
The plot could involve Natsu being sent on a special journey by the dragons for his training. Along the way, he not only masters new skills but also discovers secrets about the dragons' past and their connection to the world. He may face challenges that test his loyalty to the dragons and his own beliefs as a wizard.
They could be two well - known dragons from the original lore. Maybe Igneel, Natsu's father figure dragon, and another powerful dragon like Acnologia. However, in fanfiction, they could also be completely new dragons created by the author.
Lucy might also be an ally. She has her celestial spirits that could be a great help. For example, some of the spirits like Leo could be very powerful in combat against the dragons. Also, Erza would be a great addition. With her various armors and combat skills, she could hold off a large number of dragons while Natsu focuses on the more powerful ones among the 10000.
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.
Igneel could be one of the main dragons. Since he has a connection with Natsu in the original story, it would make sense for him to be among the dragons raising Natsu. Another could be Metalicana, as he is also a well - known dragon. Grandine might also be there, considering her importance in the Fairy Tail universe.
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.