You probably need to watch the first introductory video of the two chibis in preparation of the anime movie, Blood C: The Last Dark . As I've expected on my previous post they've released another clip featuring other characters from the series.
I'm not really sure on why they need to explain briefly about the characters, I think it would take a big part in the future aside from marketing reasons. Here's a recap of the video where Nono and Nene Motoe did a great lecturing classes. Too bad I can't review the TV series of Blood-C since I have a couple of animes that still needs to be watched.