This unnamed werewolf tried to kill Asa Fox in 1980 and had history with hunter Mary Winchester.
Background
For some unknown reason this werewolf and Mary Winchester had history. Mary had been tracking this werewolf a long time. In 1980, this werewolf chased Asa Fox through the woods and cornered him. The werewolf cut Asa's cheek and then attempted to kill him. Mary Winchester showed up and killed him by blowing his head off with a shotgun. Mary had briefly returned to hunting to tie up some loose ends. Mary then took Asa home and left. Asa's encounter with this werewolf motivated him to become a hunter.