as far i know those flames dont work on full dragons somthing about a heart full of darkness without any light left or somthing. same are the rare species like velvet wich i forgot how they called again... geez havent played this so long
@Mirego HD it's because once someone becomes a dragon they've gone to far and the curse can't be reversed anymore. They are close to death or are already dead. Velvet is he latter.
@penguin dude Too bad they did very bad in terms of advertising. Many people haven't heard of the game. At least they learnt from their mistakes, Crestoria did better advertising.