Bring 3 Dark Iron Bars, 20 Enchanted Leather, 3 Mooncloth and 4 Cured Rugged Hides to Anthion Harmon in the Eastern Plaguelands.
We didn't realize the importance of Valthalak's medallion, so it was divided along with the rest of the spoils. The first piece was taken by a dwarf named Theldren. I tried to retrieve it from him and he beat me within an inch of my life. You shall have to take the fragment by force.
Last I heard of him, he'd become a gladiator for the Dark Iron dwarves. Getting him to fight you is going to present a bit of a challenge, though.
Gather the following materials for me. You're going to need them.