The self-proclaimed masters of the underdark, Deep Dragons are a vicious and cunning breed of dragon designed to thrive in the perpetual darkness deep beneath the surface. They are Namtar's emissaries to the Dark Faeli and work tirelessly to convert and conquer them so that they might serve him. They have met with much success, as the Dark Faeli are desperate for divine blessings which their Dark Lady has long denied them.

Deep dragons are as at home in the underdark as other dragons are in the air. They can consume almost anything, down to the various molds and fungi which grow in the caverns; however, they prefer cave fish and aboleths. They are often known to maintain private fisheries in secluded underground lakes. They constantly war with other denizens of the dark, such as Illithids and the Tsochar. They rarely venture from the underdark, as they are ideally suited to its environs, though they have been known to occasionally travel to the surface to reclaim stolen treasure or take vengeance against a foe.

Deep dragons are a specialized type of Athasian Dragon unique to the underdark.