Obtain Grol's Amulet from the Shattershore in the Blasted Lands.
Grol... the ogre.
It would seem that Grol's body no longer rests with the ogres. His body, along with his amulet of power, is in a wrecked ship off the Shattershore, to the east. His amulet is the last... once combined, the three will give us access to Razelikh, and therein lies our chance to stop his madness.