Dark Sun: The Scorched World of Athas
Shadow Giants
Inhabitants of the Pristine Tower, they appear as black silhouettes with a ropey humanoid form and sparkling blue eyes.
They were sacrified by the Champions of Rajaat during their transformation into sorcerer-kings and greatly desire revenge on them.
They can command the powerful magic of the Pristine Tower and are working with the party to bring about a new Green Age for Athas.