In previous FF games most jobs/characters based on a Dark Knight concept used to have a Darkside aoe that was essentially a wave of dark energy that would cost HP to use. Obviously in XIV the name Darkside is already in use so that might need to be changed as well as the cost to use it (maybe MP instead), but it would be pretty amazing to see something similar to the dark waves seen in the DRK LB3 turned in to an offensive aoe spell to pay homage to previous game incarnations.