High Priestess Ishanah wants you to go to the Legion Teleporter at the northwestern corner of Netherstorm and use it to teleport to Socrethar's Seat. Once there, defeat Socrethar.
Performing quests for the Aldor will cause your Scryers reputation to decrease.
When facing eredar of great power, large armies are useless for the most part. Their corruptive powers over mortal souls are such that only the strongest-willed can even stand face to face with them.
Take this stone to the Invasion Point: Overlord, between Forge Base: Oblivion and Gehenna and bring your closest, strongest friends with you. Orelis and Karja will meet you at Socrethar's Seat; I will send Adyen along with them.
May the Light prevail today, <name>. May Socrethar meet his end.