Djinn

Reference: http://www.reality-smiths.com/brotherhood/codex/denizens/djinn.html

Sharing the Plane of Sky with the great dragons and drakes, the djinn are mages of immense power. But while they are both intelligent and strong willed, they all possess an unexplained and curious weakness;experienced wizards and sorcerers of Norrath have been known to summon them from their native plane and imprison them in sealed rooms and smaller devices. Some legends speak of fantastic rewards for those who release a djinn, yet others speak of the violent deaths of those who unleash them.