The Stonecrush Giants needed for this quest can be found by taking the southwest exit from Quarrystone Basin. You will find them atop many of the ridges and inside of the huts on the path leading up to Thingar. Be very cautious when dealing with these giants as they hit hard, 200+ on plate, and have around 3500 health. Bring a friend (or more). After slaying five of them return to Passel Drobe for a well earned and probably lack luster reward.