Chronicles of Khaldun: Crux of Eternity
The adamantine dragon Urthix lairs in deep a cave in the Sheltered Woods. The demon Physandos enslaved Urthix centuries ago, using the dragon as his muscle wherever necessary. When the Shields of the Sorrowfell defeated the demon, Urthix was released from the demon’s spell and was grateful enough to grant them access to its treasure hoard.
Image retrieved from http://archive.wizards.com/DnD/Article.aspx?x=dnd/4art/20090518 on December 16, 2014.