Walls of Mist 

General Information
Both Dark & Light Path quests involve obtaining 3 keys from chests in each of the sections the arches teleport you to.  These keys are then used on the 3 pedestals located in the entry area to open the exit.  You can enter the Walls as many times as necessary to obtain these keys but hold on to the keys until all 3 keys are in your possession.  This area resets each time you leave it and if you use a key and leave it is as though you never used the key once you return. 

Game issues: The pedestals seem to have a poor video interface and clicking on them with a mouse may not unlock them.  Give all 3 keys to one party member, make that member the active character and use the spacebar when facing the pedestals.  The central pillar may still give you some difficulty just jimmy around until it clicks into place.

Strategy:  The easiest way for either path to perform this quest is to use a master level invisibility spell and skulk through each of the maps keeping a close eye on your spell duration and beat feet out of there if the time gets short, recast the spell and come back in. Also a featherfall spell helps to speed things along in certain areas.

If Dark Path followers are feeling their oats and they want to try to fight their way through, well then you're stuck for the duration.  No turning back.  The reset thing again, you go out, then everybody will be there again to greet you when you return. 

If you have a party make up that prevents you from using an invisibility spell, well I only have one word of advice.... RUN!
Walls Main Map