Capturing
The main difference between Primal Dragons and Normal Dragons is the manner in which they are captured and trained. Normal Dragons are captured easily in battle, whereas Primal Dragons are only available when certain quest chains have been completed. In order to take control of a Primal Dragon, you also must have found an elemental orb of some sort.
Types
There are five types of Primal Dragons and only one type of Normal Dragon. This is because a Primal Dragon can belong to one of five Elements, whereas a Normal Dragon does not have such a classification. The Primal Dragon's classification depends on what Elemental Orb has been acquired during game play. There are five types of Elemental Orbs: Darkness, Light, Ice, Wind and Energy.
Appearance and Customization
Primal Dragons are set apart from Normal Dragons by their tribal tattoo markings. These skin markings cover the bottom half of the body and become more defined as the Dragon becomes stronger. It is possible to customize a Dragon's appearance, while customization for Normal Dragons is limited. Acquiring a Primal Dragon allows you to select the Dragon's head, tail and wing types, whereas you can only customize a Normal Dragon's skin, eyes and horn.
Strength
Primal Dragons are much stronger than Normal Dragons because they have more skills. They are more powerful during battle because they can use their Elemental powers to access a number of different attacks. Normal Dragons are not as strong, however they gain more experience and training points during battle. Primal Dragons also have a higher level of defense and can withstand attacks from a higher experienced Dragon, whereas Normal Dragons are less likely to withstand such attacks.