King Juris Khan was the legendary ruler of the city of Ureh. He was the monarch when his city and people supposedly found a route to Heaven, through their devotion to the Archangels.
In reality, the city was corrupted by Diablo (in the form of the Archangel Mirakodus, and Juris Khan was granted great power. Even when faced with the truth, he refuses to believe that his master is a demon, indicating that the corruption is complete.
He is destroyed in the events of Diablo: The Kingdom of Shadow.