It can be assumed by Gynok's last name that he is related to Vin Moltor. The Moltors are a family from Hallas who met the Blackburrow gnolls years ago. During this meeting, they seem to have made off with one of the gnolls hands. This "paw" has remained in the possesion of their family for some time.
The Moltors were cursed by the gnolls years ago, so it's not really surprising to find Gynok raised from the dead. What is surprising is that he managed to hold onto a platinum ring which is needed to restore the Paw of Opolla to it's magical state.