Akuma no Juusan-ya

Madeline, an 11-year-old girl, lives quietly in a secluded woodland mansion in southern England with her younger brother Dion, her beautiful mother, and their servant Moira. One day, Madeline meets and befriends some village children. At the same time, rumors of a number of murders in London, said to be the work of vampires, are rife. Meanwhile, an eerie shadow creeps into Madeline's peaceful and happy life...
(Source: Sukima, translated)