Speak with Sergeant Shatterskull at the Supply Caravan just outside of Thrallmar, to the east.
Though this land is full of strange new enemies, the Burning Legion is still the greatest threat to our Expedition. One of my most trusted warriors, Sergeant Shatterskull, has been studying the Legion's tactics - trying to discern the demons' true purpose in this land. Seek him out at the supply caravan just outside the southern wall.
And <name> - be wary of the Legion. Their evil cannot be underestimated.
No doubt you saw the Legion's warriors dotting the landscape on your flight from the Dark Portal. Though we defeated them at the Battle of Mount Hyjal some five years past, the cursed demons just keep coming back for more. If it's a challenge they crave, then the Horde will answer in kind!
We orcs have more than just a score to settle with the Legion. What about you, <name>? Shall I tell you of our enemy?