Your Dragon form is changed to become the Purple Dragon of Legend. As a Purple Dragon, you boast greatly increased physical and magical ability over normal dragons.
You also gain the power of clairvoyance that can be used in combat to see momentary into the future and will have bouts of random but useful visions of the future. In addition, you gain the Dragon Time power which allows you to slow time in short bursts. Your dragon breath is upgraded to allow the use of any element beyond just fire. Such as lightning, water/ice, water, earth, and more including esoteric elements like poison or shadow.
But most importantly you gain a purple dragon's signature Aether element. Which is a powerful energy with the properties of light, life, holy might, and cosmic energy. This special element can used in the form of an insanely powerful laser breath or be used for healing and with time open dimensional portals across reality. Usage of this element should be done sparingly since it is very taxing to use until fully mastered.
Also, you will gain knowledge of the Dragon Kata which is a martial art developed for usage by Dragons. You will begin with a basic level of skill in its use along with knowledge of more advanced forms.
Be aware there exists a very small chance of becoming a Dark Dragon if exposed to high levels of black magic or experiencing dark emotions and turmoil. Though strong willpower and mastery of your powers will be able to prevent this.