Archmage Timolain
Sometime ago, this item : Timolain's Phylactery used to drop from a Large Vile Slime in the Western Plaugelands. According to Allakhazam this item has a 10% drop rate, however people seeking to obtain it after the last few patches have not seen it drop, it may have dropped in error and been removed from the loot table, since it is listed as a quest item, but there is no known quest associated with it.     The reason this item is relevant is because Timolain is speculated to be the sorceror who created the Ashbringer. There are NPCs at both the Bulwark and Chillwind who speak of an archmage who worked for the Scarlet Crusade creating weapons of power. He was killed by the Crusade before any of his weapons where used, but not before he had crafted a "weapon of incredible power" for the Scarlet Highlord. According to the Ashbringer's flavor text, it is the weapon of the Scarlet Highlord, therefore the above reference must be referring to the Ashbringer.
The Tauren Bardu Sharpeye at the Bulwark, says: "Hello, I have set up camp here at the Bulwark to make my preparations for my journey into the Plaguelands. I have heard rumor that a great human wizard took up residency in Hearthglen, not terribly long ago. He was commissioned by the Scarlet Crusade to fashion their warriors and hunters new bows and guns. It's said that he completed a remarkable weapon before the crusade killed him. I guess their mistrust of the arcane has grown."