User blog comment:BannedLagiacrus/Flying Wyvern Discussion/@comment-6050823-20181030042920/@comment-6050823-20181030085300

It isn't just the Dragon Element that Doragyurasu, it is using Thunder as well. Doragyurasu is unique in the fact that it uses Dark Thunder (It isn't an actual element in-game, but is a part of Doragyurasu's lore), a combination of Thunder and Dragon. It seems to be a latent ability that Doragyurasu was able to some gain and master over time.