The siege is, by now, well under way, and now that you're done playing with slimes, it's time to move forward. Your next opponent is Hagara the Stormbinder, a shaman who has fallen under the sway of the aspect of death and now works toward the destruction of the world. Luckily for you, she's an enhancement shaman, so she's pretty easy to deal with.
The major theme for this boss is movement. Every major ability that Hagara has boils down to your moving in the correct manner in order to avoid what would be absolutely lethal damage. Moving and healing has never really been a shaman's strong point, but if you use your abilities wisely, you'll have her down in no time. (For full details of the encounters or full raid strategies, please read Ready Check for WoW Insider's boss guides.)