Leoric

King Leoric of Khanduras was one of the first to fall for Diablo's corruption after Archbishop Lazarus. He is also known as Leoric the Black King

He noticed the possession, but hid it from his priests in hope to defeat it himself. He failed the attempt to stop Diablo, and became corrupted, beheading people that disagreed with him. His once proud and rugged form became distorted and deformed. Leoric began to send his Knights to other villages to bully their townspeople into submission. The people of Khanduras who had once grown to see great honor in their ruler began to call Leoric the Black King.

Manipulated by Lazarus, Leoric got rid of most troublesome advisors by declaring war with Westmarch, sending them, including the honourable Lachdanan to their deaths against the Westmarch armies.

The King was never completely bent to be the shell for Diablo, but he was forever sealed in his tomb under Tristram, where he later was defeated by the unnamed hero who fought for Tristram, but seems to be reincarnated in Diablo III.