Kuro Shitsuji/黒執事 translates as Black Butler.
It is a manga comic by Yana Toboso set in London.
It started in 2006, it is published in Square Enix‘s boys manga magazine Monthly GFantasy.
The story follows Ciel Phantomhive, who makes a demonic contract with Sebastian Michaelis after his parents are killed.
When Sebastian finishes helping Ciel he will be able to consume his soul.
It was recently made into a movie that will be released in spring 2014.