I got this series by out of the library, thinking I could talk my six year old into letting me read it to her. (She's currently obsessed with the Rainbow Magic Fairies series). I was unsuccessful in convincing her, but it's just as well, because this is NOT a children's story.
It's a dark tale, full of sad, abused and unloved children. It's a story of revenge and hatred. It's a love story. It's full of beautiful drawings, people swapping bodies, sprouting wings, and of course (because it's manga), people trying to "protect" each other.
Fairy Cube is probably one of the most fast-paced mangas I've ever encountered. It's less than 3 volumes long (a big chunk of the 3rd volume is devoted to another story), but so much happens in the course of it, that it's almost overwhelming. Like Kaori Yuki's
other work I reviewed recently, this one does a pretty good job balancing the known and the unknown. It would definitely hold up to a second read.