Ox's job prior to the Cataclysm was to send prospective Hordearmorsmiths on a journey to find their calling. They first had to complete the quest The Old Ways for Aturk the Anvil. Ox would then give the blacksmith the quest [43] Booty Bay or Bust! (Blacksmithing), which would send them on their journey to become an armorsmith.
Ox's appearance may be a reference to Babe the Big Blue Ox, a companion to Paul Bunyan the mythical lumberjack. (American Tall Tale folklore)
Or maybe, it's a reference to Oxhorn, a machinima maker who plays a Tauren. One of his characters, Mortuus is already a NPC, so it is likely that the leader of the crew himself is somewhere in-game too...