Gone is the ability to directly play as the Zann Consortium. Now, it has been replaced with the umbrella faction, The Underworld. Players will have to quickly establish a front organization, the Crimson Dawn, under the command of a certain Zabrak, and branch out across the Galaxy. But you are not without rivals, as there are four other criminal organizations running amok in the stars. These are: The Hutt Cartel, The Black Sun, the Zann Consortium, the Pyke Syndicate. All control their own systems, but are pretty tame and don't branch out at the rate of the playable factions. This is really due to game engine limitations.
In a similar vain to the feature present for the CIS in Fall of the Republic, The Underworld must corrupt/buy these factions, which is a costly and long process. It might even take a couple missions to be completed, and once these parameters are met, the Criminal faction ins question will be annexed and corrupted by the Underworld. As well as this huge boost in credits, you are given access to their unique units, such as Black Sun infantry, Hutt space craft, and Zann vehicles.