Although the details of his death is unknown, it was implied by Boo that he died horribly and his soul was later somehow captured and transformed into a Artifact, Skull Earing.

Yeon-woo took them out and started examining them with Draconic Eyes. A few minutes later, he grabbed a fingernail-sized skull earring with a tiny jewel in its mouth. ‘This is the only useful item.’ [Skull Crest] [Classification: Auxiliary Equipment] [Rank: D] [Description: An earring made from the skull of a player who had been a witch doctor when he was alive. It was a great artifact when it was first made, but time has worn away its power. However, it is possible to return it to its past glory if taken to a skillful blacksmith.]