Dark Arts is more frustrating on the basis it uses up a huge chunk of your resource to boost one attack. But Dark Arts was deleted so it's kinda moot now. Toilet Arts is no more.

Hypervelocity is going to be amazing during Renzokuken CD period.

Hypervelocity if it frustrates anyone is going to be during No Mercy window.

But I think with Bloodfest seeing BS + HV x6 is very likely.