Wailing Caverns Instance Guide
Wailing Caverns is an instance located in The Barrens, which is almost exclusive to Horde. Wailing Caverns main quest is exclusive to Horde and is aquireable after completing a short quest chain which can be found here. However there are more quests for the Wailing Caverns as well, a few of them are located in Ratchet and a few more about the actual instance itself.
Below is a picture that will better explain how to get to the Quest NPC's that are above Wailing Caverns. (Picture acredited to whomever submitted It on WoWhead.com) Also, Since I feel it's appropriate... doesn't this picture look like scenery from Diddy Kong Racing? Hmmm what course was that..
Anyway, to get inside Wailing Caverns you will have to run through a ton of mobs, or kill your way through. There are also two quests that can you do right in the area outside of Wailing Caverns. Once you're inside you'll see a Tauren Druid that you can ask for a Mark of the Wild. The first boss you will come to in Wailing Caverns will be Lady Anacondra.
This boss is very simple. Only thing that you have to watch out for if you're doing it with a group is that she calls for help. She will call all raptors within around 100 yards to her, so clear all raptors around before you engage her.
The next boss you will come to will etheir be Kresh, who is a neutral turtle that walks along the river, or Lord Cobrahn. For the sake of arguement I will be listing Kresh first. Kresh is an optional boss and also a rare boss. So he may not always be spawned in your instance.
Kresh doesn't do anything unique, he is a very simple tank and spank.
The next boss in line is Lord Cobrahn.
Lord Cobrahn has a few snakes that circle around his feet. Nothing to worry about, they can be killed with an Arcane Explosion or a very weak auto attack. Very similar to the snakes on your way to Lord Cobrahn.
After Lord Cobrahn is dead you will be heading back towards where you killed Lady Anacondra, to the otherside of the instance. The next boss you will encounter is Lord Pythas.
Lord Pythas has one add with him, which is the only even remotly difficult part of this encounter.
After you kill Lord Pythas the next boss in line is Skum. He is another optional Boss of WC, but is never skipped.
Skum has a mean Chain Lightning for his level, other then that there is nothing else to worry about. Also, he is one of the only bosses in the game that will flee when he gets low on health.
After Skum you have two bosses, side by side. These bosses are Lord Serpentis and Verdan the Everliving. Verdan the Everliving is best known for being the "Fake" final boss of Wailing Caverns. Verdan the Everliving is most commonly the last boss people do in this instance, not often do they stick around for the final escort.
Simple tank and spank
Verdan the Everliving hits like a truck, harder then any other boss in the instance. This means the healer will have to be on guard if he wants to keep the tank and his group alive. Also he will do an AoE entangle to your group, rooting everyone in place.
After you kill Verdan the Everliving, the tauren at the entrance to the instance will shout and inform you that he has a quest for you. Go back to him and tell him you're ready to escort him to Naralex.
He will stop 3 times on the way and get ambushed by raptors and fun stuff like that. Just protect him until you get to Naralex. Here you will have to protect him against a few waves of mobs and then a giant Murloc will come out, Mutanus the Devourer. This is the true final boss of Wailing Caverns.
Mutanus will sleep your party members and also charm them. Mutanus is also said to be immune to any shadow damage. I've personally never tested it.
After you kill Mutanus make sure you loot him, he will drop a Glowing Shard which will start a quest that leads to a nice amount of XP and gear.