Slave Pens is a dungeon whose entrance is located in Zangarmarsh in the World of Warcraft game. The level range for the normal dungeon is 60-69. The only achievements you can get in this dungeon are the ones for completing. There are no achievements awards for individual boss encounters for making him to do something. The instance was released in the Burning Crusade expansion. The dungeon contains 4 bosses. The end boss of Slave Pens is Quagmirran.
Running this dungeon increases your reputation for the Cenarion Expedition faction. How much you get depends on the level and the race of the character. Humans have a racial bonus of diplomacy which means they get more rep from killing and doing things than the other races.
The Slave Pens dungeon is the left most dungeon with the exit tube behind you. The coordinates for Slave Pens is 48,35. Unlike the Caverns of Time, there is no minimap to show the location of this dungeon. In the Midsummer festival, there will be an additional boss called Ahune. He will look similar to Murmur in Shadow Labyrinth. He drops gear for the highest levels but at the lowest item level if that makes sense to you.
Ahune is a seasonal boss meaning he will only appear during the Midsummer festival. He appears in the Slave Pens dungeon.
By simply killing this boss, you will get the achievement. He is similar in style to the final boss in Shadow Labyrinth but a heck of a lot easier at the level you fight him at. There are two phases to this boss, the first phase is to kill as many adds as it is possible. After you have killed enough adds, he will turn to a crystal and the knack is to destroy the crystal in the quickest time. If you fail to destroy the crystal in the allotted time, he will re-spawn and call upon his adds. This boss will drop epic loot but it is only appropriate for the first year of the expansion, the item level of loot doesn't increase in the second year of the expansion.
Mennu will walk up and down his ramp but becareful when you pull him as you could end up pulling the whole room. The best person to pull him would be a ranged and then the tank takes over. Mennu is a shaman and he has totems at his disposal which will cause damage naturally. He also has the ability to root people to the ground but 'Every Man for Himself' and Blink does the trick to escape. The former only works if you're human as its a racial spell. The room doesn't have to be cleared if you don't want to, it is easy to do if you pull him back and kill him in an opening, he doesn't run around in the fight or push back.
Rokmar the Crackler is a giant lobster like creature and is easily killed. He has a number of ranged spells with which to cause damage to players. His common spell is Ensaring Moss which reduces attack speed by both melee and ranged by 50%. Other spells include Grievous Wounds will cause damage until healed. If you're sufficiently high enough, the damage will be negligible and nothing to worry about. He'll also throw an AOE spell which will inflict frost damage so your healing will need to get everyone back up to full strength afterwards.
Quagmirran is a moss creature that when you arrive at his location, he will be underwater. He moves slowly and if you're patient enough, he'll walk out from underwater in his own time. Before you start the fight with Quagmirran, it is recommended you get the buff from the night elf you release from the prison.
Quagmirrans main spell is nature poison which he'll apply to all or just the closest person. Given he's got such long arms, its no surprise that if you're a low level character, he'll be able to hit you back but for a high level player, it won't necessarily occur. After the fight, there is no short cut out, you'll have to use a mage portal or a heathstone.