The Black Shield (ID 27258)
The Black Shield is a Horde-only quest for level 15-30 in Dustwallow Marsh. It is step 66 of 83 in the Dustwallow Marsh storyline. The quest's turn-in marker is in Thunder Bluff at 54.0, 80.8. It rewards 2,050 experience.
Description
Ah, I remember now! Mosarn is a well-respected blacksmith in Thunder Bluff. I knew I had heard his name somewhere, before.
In thanks, the Earthen Ring awarded me with a set of armor crafted by Mosarn. Very good work.
Perhaps he can tell you more about the shield he crafted.
It's not much of a lead, but since we didn't get anything useful out of Reethe, it's all we have.

