Read the Glyphic Scroll and speak to Isabella in the church in Deathknell.
Ah, while you were off dealing with the mindless Scourge, this scroll arrived for you. I would think it's some matter of importance as it seems it bears the seal of the mage trainer Isabella. I would take some time to read it before heading out again.
I knew you would come to me, <name>. Not because you do not have the will to follow your own path, but because we are kindred spirits. We both have felt pain. We have both suffered. And now we want the power to take back what we know is ours: this land, our lives, our destinies. But there is much for you to learn still.
You must return to me often if you are to become powerful enough to destroy those who would oppose us. The rules of magic still apply to you, <name>. You will still find corruption follows you like hungry wolves in the night. You will find its caress is not unlike an addiction, an old lover still wanting to be by your side. But these things can be staved off. These things will only control you if you allow them to.
Go now, return to me when you've grown more powerful.