Secure the Eastern Ley Line and Western Ley Line beneath Karazhan.
Karazhan sits upon a confluence of ley lines. It's why this location was chosen for the tower in the first place... a fact that has not escaped the Legion's notice.
If the demons are tapping into these lines of power, they must need their energy for something particularly menacing. You must cut off their access to the ley lines if we're to have a chance of retaking the tower, <name>.