The shyness feeling seems to be mutual, even if Kuro's significantly more outgoing. Perhaps it has something to do with the taboo nature of their incestuous relationship (see the tags)
Nico and Hanayo would make a great pair. They'd go on idol concert/event dates together and just fangirl over cute idols. Then in the end, they end up fangirling over each other.
@Shizuku-chan just like it's your opinion that Umi is the best it's mine that she's completely boring. Did you get that offended that someone doesn't like your favorite character? Grow up