The blond is not a girl. The blond is a male, named Keiki. And the girl (the one with wings and blue hair) is his 'mother', in a sense. She is not 'Kaiko'. Therefore, I'm removing that tag.
:] The series is called The Twelve Kingdoms in english. It's amazing. In japanese, it's called Juuni Kouki. It's fantasy/ partial romance. But not really. xD There's lots of action.
Kaiko IS the name of Keiki's Nyokai... You can pick up The Twelve Kingdoms books or even google it, and it will show that Kaiko is correct. Therefore, I'm putting the tag back.