“Summon a pillar of darkness that constantly inflicts pain on enemies who come in contact with it. Targets continue to receive momentary damage even after moving away from the pillar, but that damage weakens over time.”
First of all, the damage doesn’t weaken at all. It does full damage through out the entire 16 second debuff, which is the same damage that Pole of Agony does each tick. Second, the debuff isn’t applied at all if enemies remain within the circle for the entire duration, which means they take about 1/4th as much damage or something if they don’t move out of it.
Not only is this not at all what the tooltip indicates, it’s quite counter-intuitive that you’d have to kite monsters out of it just for it to do more damage. It would make more sense if the dot part was also applied when the AoE runs out.