Patch 10.1 will feature a new nine boss raid called Aberrus, the Shadowed Crucible! Described as the horrific place where Neltharion went mad, the raid will follow Scalecommander Sarkareth of the rebellious Sundered Flame as he as seeks power within the forgotten secrets of the Black Dragonflight. Meanwhile, Wrathion, Sabellian, and Ebyssian will each grapple with the legacy of Deathwing.
WARNING: Story spoilers for Patch 10.0.7 ahead!Click to expand!
Breach Neltharion’s secret laboratory hidden within Zaralek Cavern. It is here that he created the dracthyr and ultimately succumbed to the whispers of the Old Gods and their corruption. Players will face nine new raid bosses in an effort to thwart the incarnates as well as Scalecommander Sarkareth, whose forces seek to claim the legacy of the dracthyr.Concept art for Aberrus includes a large inner sanctum and various experimental test tubes, as well as a Lava Hydra and Elementium Dragon. The Elementium Dragon is described as a prototype for Deathwing, reanimated using Shadowflame. See more detail in the concept art overview. While we don't know much about Aberrus itself, we actually heard the name already during the Warden of the Forbidden Reach storyline in Patch 10.0.7. Through a series of collected journal entries, it tells the story of Adamanthia, a Black Dragon sent to on behalf of the Neltharion to report on the Forbidden Reach sometime after the original imprisonment of Raszageth. Over the course of the entries, she becomes disillusioned with Neltharion's increasingly unhinged decisions, and in Sending Stone: Protest, she appears very troubled by the idea of newly awoken Dracthyr being sent to Aberrus.
Transcription of Sending Stone: Protest My Aspect. I Read more on wowhead.com