Board Thread:Dragon City Gameplay Questions & Answers/@comment-24724301-20140323070348/@comment-24687553-20140324140349

This also means that the higher the category of the dragon (1-5), the more damage it packs in combats. The ranking system based on the number of stars also increases the damage of the dragons. Higher ranking dragons can deal  higher damage and have more HP. The reason why some dragons with no stars fare much better in combat compared to some stared ones is due to their category. Dragons from a much higher category (4 or 5) deal much more damage compared to some dragons from lower categories even though they have more stars. The category of a dragon plays a more significant role in determining the amount of damage that can be dealt than its ranking.