Finally.
After topping people’s most wanted mounts list for a long while, we finally get a Deathwing mount!
From wowhead:
“While we don’t know the exact details of the 15th anniversary celebration yet, we were told there were challenges which would involve old bosses, such as Kael’Thas. Completing all of these challenges will reward players with the Obsidian Worldbreaker dragon mount—fitting, with all the talk of N’Zoth returning and his past history with Deathwing…not to mention Wrathion’s Blacktalon Agents everywhere in Battle for Azeroth.”