Every Seven years, dragon slayers go through dragon mating season. What happens if Natsu's younger sister comes to help them and make sure that goes the way it supposed to happen. Also what if the dragon slayers had a dragon form but hide from their guilds. What if the first gen dragon slayers had a secret and they know it plus Natsu's younger sister knew about the secret.
Natsu's dragon form
Gajeel's dragon form
Sting's dragon form
Rogue's dragon form
Wendy's dragon form
Laxus's dragon form
Cobra's dragon form
Nova's dragon form (Natsu's younger sister)
All the artworks are not mine so I don't take credit for their amazing work.