KMST 1.2.442 - Angelic Burster

But by "attacks", do they mean skills or hits?

As in, would a four hit skill blow the entire buff?

Probably for every activation of a skill.
Not sure how it would work for stuff like Hurricane. Having a 50% buff to it for the duration of holding down the skill 4 times is nuts, but having a 50% buff for the first 4 shots is nuts too.