Dark Lord

Dark Lord is apparently the title of the leader of the Death Eaters.

Description and History
The title of Dark Lord was created by Tom Riddle for himself, and, in accordance with this, he referred to himself as Lord Voldemort. The name of Dark Lord referred simultaneously to his proficiency in the Dark Arts and to his properly lordly power over his followers.

The only known holder of the title of Dark Lord to date is Tom Riddle himself (to the point that many once referred to Riddle as "the Dark Lord"). However, it could properly be applied to any evil wizarding overlord with sworn, borderline-enslaved followers.

Known holders

 * Tom Riddle