Originally Posted by
Skies
Uhn... I'll add this here given my experiences: Deepvoid Slave, like any other boss battle in this game, requires having a good synch with your party regardless.
My LS took like 8~ or so tries (with 3 out of our 8 having done that fight and won it previously, also a handful of us were derping there) until we realized that actually attacking that sucker from the back IS a good idea, if used properly. The thing is, if you attack it from the back it'll do the elbow drop, which is a conal AoE, and that takes priority over all of it's other moves, so you can essentially keep it busy elbow-dropping all the time and prevent it's AoE skill and prevent it from causing too much damage to the tank.