Never got asphyxiation bubble to workUse fear (asphyxiation bubble and gigas guillotine) and sniper ring +3 and end your turns with gungnir equipped. You need hard break to break her (and enough luck but that probably isn't a problem). You can use ring of rebellion or club +10 for that. Also check your difficulty.
Didn't think about hard break, to be honest, just defended through her charged turn and tanked it out.