Players level 75 may go to the Violet Citadel in Dalaran to talk to Rhonin. He starts a quest titled: Discretion is Key. You end up talking with Warden Alturas near the Violet Hold (prison) who gives you the Violet Key to open the gates to the Violet Hold.

This dungeon is scripted in the same fashion as Black Morass in Caverns of Time. You will see portals opening up one at a time. A dragonkin (portal keeper) will pop out and whelps pour out from the portal. You must kill the portal keeper and anything coming out. If they reach the exit door, and cast continually on it, the event resets and you lose.

Every five waves (approximately) one of the dragonkin will run to a random prison cell to shut down the magical wards allowing the prisoner to escape to attack you. From observation, each time you run Violet Hold, you will face two random bosses.  The third and final boss is Cyanigosa, a blue dragon. There were more cells with bosses, so definitely you are encouraged to run this dungeon many times for a shot at different and random loot tables from each of the bosses. Each dungeon run lasts around 35 minutes. In the video below, my first time in beta build 8905, we faced Erekem and his two guards (Arakkoa), Zuramat the Obliterator (Void Walker). In the cells, there is a two-headed magmadar-like dog, and one of those floating brain-like demons such as the first boss in Auchenai Crypts.  Near the sewer pool in Violet Hold is an imprisoned War Golem, and one of the lower prison cells has an Ethereum prisoner. There is obviously a variation to the two possible random bosses you might face in each run with decent loot.