Whether you were spared the fate of being sundered or have been rejoined later on you have become an Unsundered ancient of Etheirys.
You have gained complete mastery of the echo and all of its power, the potency of the power itself is greatly increased.
You are practically immortal, you do not age past your prime. Even when your body is completely destroyed you can simply fashion a new one. It would take the complete destruction of your soul to completely kill you but even then it would be difficult requiring a tremendous amount of magical power to destroy it.
Your personal reserve of magical power is immense and it is 14 times denser than before giving any magic you wield increased potency. You can also transform into a combat form the look of which you can customize.
This Aetherial density also allows you the ability to use creation magic which allows you to conjure and create anything you can think of and imagine as long as you know have enough magical power to create it, this even includes creating life itself. Thought creation magic takes great concentration to use and it is not an art that is commonly used in combat