You can get the mage stronghold by talking to tolgeras in the goverment district. He will tell you to hunt down valgar corthela (something like that). He can be found in the umar hills in his cabin. (north part of map) then go to the planar sphere in the slums and complete the mission from there. If you need anymore help, just e-mail me at
dirkduck169@hotmail.com or whatever.