Kuroshitsuji, also known as Black Butler, is a dark fantasy anime series that follows the story of Ciel Phantomhive, a young earl in Victorian-era England, who is aided by his loyal and mysterious butler, Sebastian Michaelis. The series combines elements of mystery, action, and supernatural themes, as Sebastian is revealed to be a demon bound by a contract to serve Ciel. Together, they solve crimes affecting the Queen of England while pursuing Ciel's personal vendetta.