Each mob can not be more than 3% apart on health. A curse will land on your tanks that will drop all potency in that group until it is cured. Each mob at different times will go into a ghost form at which they must be dragged into the central tornado that will spinning in the middle of the room. Your raid needs to have as much MITIGATION as possible. At least 40,000 Mitigation per raid member or the power drain will become almost unmanageable.