The Warlord's Hideout

There are benefits to hiding very, very quietly at the entrance of your enemy's hideout. Just hours ago I saw a group of naga go through the stone archway on the second tunnel from the left. I'm not well versed in their language, yet I clearly understood one word: Kalithresh. That must be the entrance to the steam vaults, where Warlord Kalithresh has been commanding his troops from. You must find him and stop him. I am too weak to be of any assistance.