Lilith the Lithe is a level 55 weaponsmith located in Everlook in the contested territory of Winterspring. She has two hobbies - dancing, and threatening to kill people who get too close to her.
She is also one of the most skilled hammersmiths in all of Azeroth, and might be willing to train people who do her an appropriate favor.
To this end, she starts the quest  Sweet Serenity (Blacksmithing, Dungeon). It is not required to do this quest in order to become a master hammersmith.
See List of Winterspring NPCs.