Report to Gor'mul at Hammerfall in Arathi Highlands.
You have served us well here, <name>. Now that we've made our mark, the next phase of our conquest will occur over months rather than minutes.
There is much work yet to be done, and I will spare you the tedium of waiting for our fortifications to trickle in. Travel to the east, to Hammerfall. The orcs there will no doubt have use of your aid.