First completely correct picture of Kotobiwa.  Kotobiwa is named after two instruments, the Koto and the Biwa.  Put them together, you get the Mayakashi, that thing she plays.  Oyasumi means "Good night."  I happen to think it sounds pretty.  The character design is styled after Houshin Engi.  Her unique glove thing came about pretty much because I thought KiHakuyuukou's (anchan's!) claw-picks were nice.