A lost master is a title given to a player who has mastered their chosen field in World of Warcraft. In order to be considered a lost master, one must have completed all available quests, raids, and dungeons within their chosen field. In return, lost masters receive a gold plaque with their name and server on it. They are also able to purchase a Lost Master Tabard, which is a rare tabard that can be worn to show other players that they are a lost master.
Leveling
