From WoWWiki
The Obsidian Dragonshrine is a site of charred ground to the south of Fordragon Hold at 39.1, 31.9 in the Dragonblight. Like the Ruby Dragonshrine is to the red dragonflight, this place is the sacred place of the black dragonflight.
Also like the others, it is being desecrated by the Scourge, and adventurers are sent there by a bitter Nalice to aid Serinar in defending it. Its constant smoldering nature is reflective of the dragonflight's destructive nature, and is likely not due to the actions of the Scourge.
