Patch 3.3.5's Ruby Sanctum is currently open for business. Players can enter the instance at this time and kill the trash and minibosses, and Halion is able to be engaged. We've not yet received word on whether or not he's killable, or whether anyone has killed him.
These developments demand an immediate response, but the dragons of the Wyrmrest Accord are wracked with questions. Next to nothing is known about who might be responsible for the assault on the Ruby Sanctum: the black dragonflight is not known for forgiveness or patience, but its numbers in Northrend are surely limited. What force would be powerful or daring enough to assail the stronghold of these ancient wyrms? How could such an enemy sneak by the temple's guardians undetected? Surely an approaching air or ground force would have been caught by Wyrmrest Temple's defenders.