This is the instanced zone involving the group task "Meeting Adjorned" in which you must enter the command center of Korafax and kill four of the Discord Army's officers.
Even without mercenary easily soloable at 95. The bosses come one by one. Only Pixxt might be a little pain if she gets her adds up, but you can kill the adds before engaging the next boss, he won't aggro himself.
Another named discordling spawns in this instance. Its name is Spikemangler and it can spawn in the same area the ferans normally spawn in Korofax. He has a damage shield on him but other than that its a pretty straightforward fight.