Ah, I've just started reading this manga, and it's really awesome! Kaori Yuuki has done it again and made another great manga!!! Her other works include Angel Sanctuary and Godchild, and all of her manga have a dark, and sometimes eerie twist to them. The relationships are dark and twisted as well... incest, master and creator, as well as psychologically twisted homosexuals. There's a necrophile in Ludwig Kakumei as well! So, onwards we go into the realm of darkness of the human mind, and into another great story!
I particularly like this manga because of the implementation of music, added on with the fact that it's created by my favorite mangaka. She has also made a yaoi called Boys Next Door, which is also twisted and depressing as well. Her storylines are the best!