Blizzard has announced that the Patch 10.1 campaign finale is locked behind a Scalecommander Sarkareth kill in the Aberrus raid until Sarkareth becomes available in LFR the week of June 20th.
Just want to be very clear–
The final chapter for the Embers of Neltharion questline will open up to all players, regardless of their personal raid progression, when Scalecommander Sarkareth becomes available in Raid Finder.That story is related to the end of the raid.
