Still works just fine as a fod~
And it has no effect on rage bar depletion, it only applies to damage directly. So for example Belphegor would still deplete only the 30% of the current ragebar with the depletion effect even if you stack 3x3 maxed mode gauge reduction effect. In fact, ironically enough it will relatively have a lower effect since the nuke she does first will get the effect, leaving a lower remaining rage bar of which it depletes the 30%.