while it would take a lot of testing and finagling it's probably possible for ibuki with powermod to be outdamaged in practice since applying it requires summer wu, whose other value can likely be beaten by having a better support instead
insane that they give saber a buff that makes her attack up for self 50% for 3 turns and ibuki's still stuck with that terrible 3 hit limit on her 40% attack up.
these don't consider outside buffs at all, though i could throw generic support buffs on another round of calcs since it's not like this context would differ in logical support picks.
that said, same buffs applied, i'm fairly confident the same pattern would show
after some research and testing, it has been discovered that foreigner hokusai, and ONLY her, doesn't receive a second instance of her third skill's on-attack effect when using the skill again before the buff expires from the previous use. (example video provided)
@TokuHer0@einseiber regarding the attack up point here, bakin has perhaps the most comparable effect of this type, with 15% attack up after arts cards (including np), and that one stacks too, despite being better, since it carries over and has a higher cap.
due to the otherwise universal ability to stack the effect, i believe that hokusai's implementation is an unaddressed bug dating to her initial release, as well as a failure to notice and correct the behavior to match all other servants when the skill was buffed.
as the example shows, both passionlip and chiyome (who were added to the game before hokusai) can stack their own on-attack effects without issue. this is true of all other playable servants' effects of this type. the only exception is specifically foreigner hokusai.
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