Mortak Shieldbiter

According to Kyðeon, as told to the party:

“The Scion of the Dwarves is Mortak Shieldbiter, who is living in Grünvik currently; and I have met him a number of times. I must admit that the change in the legendary blade Zhêlkurk to the new blade which Darvok last carried here, the flame-blade Laima carries, and the Óbreyttur the Omen bears, all appear to bear his technique, but not his mark. I was wondering if you found him already, or if you knew who fashioned these articles, for they bear the presence of Mortak’s work, but look like they were executed by another hand.”