There are many types of ghosts, some friendly, some mischievous and others deadly. Dark Souls 2 allows you to interfere as a ghost type spirit in another player's game; to do as you wish. A plethora of new images have arrived showing a bunch of Poltergeezers and Poltergals.
Dark Souls 2 is due out in March 2014 and will have three player online co-op. Check out the Co-Optimus hands on preview for some co-op action in motion.
Source: Trueachievements.com