Enkidu, Nephalem Traitor, is a Unique Ghoul found in the Festering Woods in Act I of Diablo III. He spawns for the Eternal War event. Judging by his title, he may be one of the nephalem who betrayed their kind during the Sin War, cursed to exist in a ghoul form.
In combat, he has Fast and Knockback affixes. Killing him is required to complete the event.