I'm not too far into this manga, due to the fact that i've been reading it online and only 15 chapters have been released so far. From what i have read, i found it to be very good. There are quite a few surprising twists in just the first 15 chapters. Originally based around the Vampire king deserting his nation in order to find the queen,while being sought by the "Black Swan", It quickly turns to a story of revenge and intrigue. The action in the story so far is good, with the Vampire King leading in power, but slightly surpassed by the "Black Swan" in strength. As I finish the manga (god, knows how long that'll be), I'm sure i'll find it to be very good.