Complete 86 quests in Blade's Edge Mountains.
I was stuck at 84/86. I hadn't done Netherstorm yet, and from reading up on it, found that there was a Consortium quest that sends you to Blade's Edge that counts as a Blade's Edge quest. There is a follow-up to it as well. You have to have Revered rep with Consortium.Commander Ameer near Manaforge Ultris (59,32 in Netherstorm) sends you to Image of Commander Ameer in Bash'ir Landing (52,15 in Blade's Edge) who gives quests that take place in Blade's Edge.After completing Into the Nether with a few quests to spare, I got my rep up with Consortium through the process of questing, which involved farming a total of 7 Ethereum Prison Keys for quest turn-ins for Commander Ameer. Upon reaching Revered rep, he offered Stasis Chambers of Bash'ir.I went to Bash'ir Landing and fought Thuk the Defiant. He wasn't too rough (I was playing a level 80 combat rogue) and managed to solo him. He shouldn't be a problem for a lot of classes to solo with decent gear, especially if you can heal. Of course anyone at level cap will not have any trouble at all.After completing Stasis Chambers of Bash'ir, you can pick up The Mark of the Nexus-King and Purging the Chambers of Bash'ir. You will need to collect 5 Ethereum Prison Keys in order to get Ethereum Stasis Chamber Key. You use those to unlock the chambers to fight a mob that may or may not drop the Mark of the Nexus-King that you need for the quest The Mark of the Nexus-King.