On paper, the fight itself looks like it has a lot going on. Luckily, as hunters, we have a very simple job to do. You have to DPS the boss, hit adds when they’re up, and react appropriately to debuffs.
First off, spread out to avoid the chain lightning. Second, when you’re DPSing the boss, tranquilizing shot him if he has a nether power buff.
He’ll spawn a mistress of pain, which looks like a very large warlock’s pet. This needs to be taken down before going back to the boss- generally your raid leader will want it tanked next to the boss, and since it’s easy to mouse target, you probably won’t need a targeting macro. The reason you need to kill it first is that is does random raid damage, and quite a bit of it.
He’ll also spawn green volcanoes that will drop a couple of felflame infernals. These have very few HP, but need to go down fast and be interrupted whenever possible. If you’re marks, save your silencing shot for them. If it charges you, run away, but not in a direction that would have it run over other players.
There are two debuffs you need to be aware of (and deadly boss mods should warn you about them). The first is incinerate flesh, and this forces your healers to heal you for a large amount in a short period of time, or else you explode. When you get it, stay where you are, or at least ensure that you’re in range of healers. If there’s any doubt, move to a more central position.
The second debuff you need to watch for is legion flame. This will spawn many circles of fire around you, every couple of seconds. If you get it, you need to run around the room, making sure never to drop a fire next to a player. Generally, there will be an established path for you to take agreed upon ahead of time.
That’s all there is to this boss- unless you’re a healer or a tank.