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.