Is the "unforgiving" part some sort of joke? I'm not familiar with the series.
Hibiki ButtHibiki BreastsHibiki EyesA very unforgiving brain capacity.A very unforgiving shade of blue. Blue!Hibiki VoiceA very unforgiving voice. Very.Hibiki ArmpitsEmits very unforgiving pheromones.A very unforgiving softness. The size is also unforgiving.Very unforgivingly high-quality hair. Easy to distinguish from Rin-chan.A very unforgivingly firm shape.Hibiki BrainsHibiki HairProbably would be a close friend with Yumehara Nozomi.