The Black Morass - Opening the Dark Portal is a dungeon whose entrance is located in Tanaris in the World of Warcraft game. The level range for the normal dungeon is 68-75. 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 3 bosses. The end boss of The Black Morass - Opening the Dark Portal is Aeonus.
Running this dungeon increases your reputation for the Keepers of Time 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 Black Morass is also known as 'Opening the Dark Portal', it is a dungeon that is set within the Caverns of Time in Tanaris. The dungeon group is sent back in time to the Swamp of Sorrows when Medivh was opening the Dark Portal on Azeroth. The Infinite Dragonflight is attempting to travel back in history and alter the timeline which is where you come in, you need to prevent them from preventing Medivh from opening the portal.
If Medivh doesn't open the portal, history will be changed forever and untold damage will be done to the fabric of time. The dungeon is simple, you need to stop eighteen waves of attack, on every sixth wave, a boss will spawn. Whilst some trash looks deceptively low, the actual dungeon elites aren't so easy, you can avoid the non-elite creatures. There are three bosses in total with Aoenus, a large dragon being the main boss. In this dungeon, you are able to gain rep with the Keepers of Time and can be either faction.
Once all the bosses are complete, the Portal will open and the Orcs will come through. It used to be a required dungeon for the Karazhan raid attunement quests but that is no longer the case.