There are some lists earlier in the thread. For Dalaran, I've only ever seen Armond Thaco and Lord Adder.
What weirds me out about Thaco is that you also fight an Armond Thaco during the Destruction Warlock artifact chain - as an undead caster in Baradin Hold. It seems unlikely they would tie a clue to something only another class can do, but it still struck me as strange. Why do two different mobs have the same weird name?
The flavor text of the item says, "A dark weapon from a long dead master, hungering to taste blood again." Based on that description, I thought there was a chance it could be from Hakkar the Houndmaster out on the Broken Isles - since he's a long dead (killed by Malfurion in the War of the Ancients) master (Houndmaster), and the tooth-like style sort of suits hounds. You get it. Anyway, no luck. He didn't drop anything.