Oben Rageclaw wants you to kill his soulless body, and then use the Voodoo Charm.
After examining this charm, [player], I see now what must be done. Please take it, and do as I ask.
You are to explore the deepest areas of the Ban'ethil Barrow Den. There, you will find my soulless body... Although I regret what I am about to tell you, I see no other way to free myself from the control of the Gnarlpine.
In order for me to escape them, you must kill my physical form. Once that is done, use the voodoo charm on my fallen body. After you have completed this task, please return to me.