Find Koren inside Karazhan.
Now that we've found a way back into Medivh's Tower - or rather you have - the first thing we need to do is try to get a sense of what the situation inside is.
One of our agents who had managed to infiltrate Karazhan kept an encoded log of her observations. Unfortunately her death was confirmed shortly before Karazhan was shut down. Koren, Karazhan's blacksmith, was under our pay. Though not a member of the Violet Eye, he should be able to help us find Keanna's log. Look for him inside.