Godchild 1 and 2 by Kaori Yuki

Godchild is the story of a Victorian aristocrat named Cain, his 10 year old half sister Mary Weather, insane homicidal half brother Dr Jizabel Disraeli, their sadistic absent father and Cain's young butler Riff. Cain is a collector of poisons and detective and Godchild 1 and 2 cover a couple of his cases investigating murders, suicides and hauntings.

Yuki is the creator of Angel Sanctuary (which I've just started reading) and Cain and is female. Godchild is from the Shojo Beat house (shojo - young women) and is a far cry from the kind of shojo I don't like - high school romance and girlish crushes on older more powerful men. There is the usual mobile sexuality of manga that is both odd and entralling to my westernised mind, the androgny of Cain and Dr Disraeli, the overt exercising of Cain's power over society girls and the tensions in the relationships between Cain and Mary and Cain and Riff. After reading twice I may be hooked

It would have been really interesting to see these stories written and drawn in a westernised style along the lines of The League of Extraordinary Gentlemen, this is definately a fantasy of Victorian London although there are elements of what it would have been like